Commit Graph

15614 Commits

Author SHA1 Message Date
Oleg Nesterov
c1ae5c75e1 uprobes/tracing: Introduce is_ret_probe() and uretprobe_dispatcher()
Create the new functions we need to support uretprobes, and change
alloc_trace_uprobe() to initialize consumer.ret_handler if the new
"is_ret" argument is true. Curently this argument is always false,
so the new code is never called and is_ret_probe(tu) is false too.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:32:02 +02:00
Oleg Nesterov
a51cc60417 uprobes/tracing: Introduce uprobe_{trace,perf}_print() helpers
Extract the output code from uprobe_trace_func() and uprobe_perf_func()
into the new helpers, they will be used by ->ret_handler() too. We also
add the unused "unsigned long func" argument in advance, to simplify the
next changes.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:32:01 +02:00
Oleg Nesterov
457d1772f1 uprobes/tracing: Generalize struct uprobe_trace_entry_head
struct uprobe_trace_entry_head has a single member for reporting,
"unsigned long ip". If we want to support uretprobes we need to
create another struct which has "func" and "ret_ip" and duplicate
a lot of functions, like trace_kprobe.c does.

To avoid this copy-and-paste horror we turn ->ip into ->vaddr[]
and add couple of trivial helpers to calculate sizeof/data. This
uglifies the code a bit, but this allows us to avoid a lot more
complications later, when we add the support for ret-probes.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:32:01 +02:00
Oleg Nesterov
0e3853d202 uprobes/tracing: Kill the pointless local_save_flags/preempt_count calls
uprobe_trace_func() is never called with irqs or preemption
disabled, no need to ask preempt_count() or local_save_flags().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:32:00 +02:00
Oleg Nesterov
456fdbcb86 uprobes/tracing: Kill the pointless seq_print_ip_sym() call
seq_print_ip_sym(ip) in print_uprobe_event() is pointless,
kallsyms_lookup(ip) can not resolve a user-space address.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:31:59 +02:00
Oleg Nesterov
07720b63a9 uprobes/tracing: Kill the pointless task_pt_regs() calls
uprobe_trace_func() and uprobe_perf_func() do not need task_pt_regs(),
we already have "struct pt_regs *regs".

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: Anton Arapov <anton@redhat.com>
2013-04-13 15:31:59 +02:00
Anton Arapov
a0d60aef4b uretprobes: Remove -ENOSYS as return probes implemented
Enclose return probes implementation.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:58 +02:00
Anton Arapov
ded49c5530 uretprobes: Limit the depth of return probe nestedness
Unlike the kretprobes we can't trust userspace, thus must have
protection from user space attacks. User-space have  "unlimited"
stack, and this patch limits the return probes nestedness as a
simple remedy for it.

Note that this implementation leaks return_instance on siglongjmp
until exit()/exec().

The intention is to have KISS and bare minimum solution for the
initial implementation in order to not complicate the uretprobes
code.

In the future we may come up with more sophisticated solution that
remove this depth limitation. It is not easy task and lays beyond
this patchset.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:58 +02:00
Anton Arapov
fec8898d86 uretprobes: Return probe exit, invoke handlers
Uretprobe handlers are invoked when the trampoline is hit, on completion
the trampoline is replaced with the saved return address and the uretprobe
instance deleted.

TODO: handle_trampoline() assumes that ->return_instances is always valid.
We should teach it to handle longjmp() which can invalidate the pending
return_instance's. This is nontrivial, we will try to do this in a separate
series.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:57 +02:00
Anton Arapov
0dfd0eb8e4 uretprobes: Return probe entry, prepare_uretprobe()
When a uprobe with return probe consumer is hit, prepare_uretprobe()
function is invoked. It creates return_instance, hijacks return address
and replaces it with the trampoline.

* Return instances are kept as stack per uprobed task.
* Return instance is chained, when the original return address is
  trampoline's page vaddr (e.g. recursive call of the probed function).

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:57 +02:00
Anton Arapov
e78aebfd27 uretprobes: Reserve the first slot in xol_vma for trampoline
Allocate trampoline page, as the very first one in uprobed
task xol area, and fill it with breakpoint opcode.

Also introduce get_trampoline_vaddr() helper, to wrap the
trampoline address extraction from area->vaddr. That removes
confusion and eases the debug experience in case ->vaddr
notion will be changed.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:54 +02:00
Anton Arapov
ea024870cf uretprobes: Introduce uprobe_consumer->ret_handler()
Enclose return probes implementation, introduce ->ret_handler() and update
existing code to rely on ->handler() *and* ->ret_handler() for uprobe and
uretprobe respectively.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-13 15:31:53 +02:00
Namhyung Kim
20079ebe73 ftrace: Get rid of ftrace_profile_bits
It seems that function profiler's hash size is fixed at 1024.  Add and
use FTRACE_PROFILE_HASH_BITS instead and update hash size macro.

Link: http://lkml.kernel.org/r/1365551750-4504-1-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 23:02:33 -04:00
Namhyung Kim
ed6f1c996b tracing: Check return value of tracing_init_dentry()
Check return value and bail out if it's NULL.

Link: http://lkml.kernel.org/r/1365553093-10180-2-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 23:02:32 -04:00
Namhyung Kim
f1943977e6 tracing: Get rid of unneeded key calculation in ftrace_hash_move()
It's not used anywhere in the function.

Link: http://lkml.kernel.org/r/1365553093-10180-1-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 23:02:31 -04:00
Namhyung Kim
9f50afccfd tracing: Reset ftrace_graph_filter_enabled if count is zero
The ftrace_graph_count can be decreased with a "!" pattern, so that
the enabled flag should be updated too.

Link: http://lkml.kernel.org/r/1365663698-2413-1-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 23:02:30 -04:00
Steven Rostedt (Red Hat)
7f49ef69db ftrace: Move ftrace_filter_lseek out of CONFIG_DYNAMIC_FTRACE section
As ftrace_filter_lseek is now used with ftrace_pid_fops, it needs to
be moved out of the #ifdef CONFIG_DYNAMIC_FTRACE section as the
ftrace_pid_fops is defined when DYNAMIC_FTRACE is not.

Cc: stable@vger.kernel.org
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 17:12:41 -04:00
Namhyung Kim
6a76f8c0ab tracing: Fix possible NULL pointer dereferences
Currently set_ftrace_pid and set_graph_function files use seq_lseek
for their fops.  However seq_open() is called only for FMODE_READ in
the fops->open() so that if an user tries to seek one of those file
when she open it for writing, it sees NULL seq_file and then panic.

It can be easily reproduced with following command:

  $ cd /sys/kernel/debug/tracing
  $ echo 1234 | sudo tee -a set_ftrace_pid

In this example, GNU coreutils' tee opens the file with fopen(, "a")
and then the fopen() internally calls lseek().

Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-12 14:43:34 -04:00
Tejun Heo
26d5bbe5ba Revert "cgroup: remove bind() method from cgroup_subsys."
This reverts commit 84cfb6ab48.  There
are scheduled changes which make use of the removed callback.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rami Rosen <ramirose@gmail.com>
Cc: Li Zefan <lizefan@huawei.com>
2013-04-12 10:29:04 -07:00
Thomas Gleixner
f2530dc71c kthread: Prevent unpark race which puts threads on the wrong cpu
The smpboot threads rely on the park/unpark mechanism which binds per
cpu threads on a particular core. Though the functionality is racy:

CPU0	       	 	CPU1  	     	    CPU2
unpark(T)				    wake_up_process(T)
  clear(SHOULD_PARK)	T runs
			leave parkme() due to !SHOULD_PARK  
  bind_to(CPU2)		BUG_ON(wrong CPU)						    

We cannot let the tasks move themself to the target CPU as one of
those tasks is actually the migration thread itself, which requires
that it starts running on the target cpu right away.

The solution to this problem is to prevent wakeups in park mode which
are not from unpark(). That way we can guarantee that the association
of the task to the target cpu is working correctly.

Add a new task state (TASK_PARKED) which prevents other wakeups and
use this state explicitly for the unpark wakeup.

Peter noticed: Also, since the task state is visible to userspace and
all the parked tasks are still in the PID space, its a good hint in ps
and friends that these tasks aren't really there for the moment.

The migration thread has another related issue.

CPU0	      	     	 CPU1
Bring up CPU2
create_thread(T)
park(T)
 wait_for_completion()
			 parkme()
			 complete()
sched_set_stop_task()
			 schedule(TASK_PARKED)

The sched_set_stop_task() call is issued while the task is on the
runqueue of CPU1 and that confuses the hell out of the stop_task class
on that cpu. So we need the same synchronizaion before
sched_set_stop_task().

Reported-by: Dave Jones <davej@redhat.com>
Reported-and-tested-by: Dave Hansen <dave@sr71.net>
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Acked-by: Peter Ziljstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: dhillf@gmail.com
Cc: Ingo Molnar <mingo@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1304091635430.21884@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-12 14:18:43 +02:00
Wei Yongjun
c481420248 perf: Fix error return code
Fix to return -ENOMEM in the allocation error case instead of 0
(if pmu_bus_running == 1), as done elsewhere in this function.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Link: http://lkml.kernel.org/r/CAPgLHd8j_fWcgqe%3DKLWjpBj%2B%3Do0Pw6Z-SEq%3DNTPU08c2w1tngQ@mail.gmail.com
[ Tweaked the error code setting placement and the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-12 06:33:56 +02:00
Linus Torvalds
a3ab02b4c5 Power management fixes for 3.9-rc7
- System reboot/halt fix related to CPU offline ordering
   from Huacai Chen.
 
 - intel_pstate driver fix for a delay time computation error
   occasionally crashing systems using it from Dirk Brandewie.
 
 /
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Merge tag 'pm-3.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fixes from Rafael Wysocki:

 - System reboot/halt fix related to CPU offline ordering from Huacai
   Chen.

 - intel_pstate driver fix for a delay time computation error
   occasionally crashing systems using it from Dirk Brandewie.

* tag 'pm-3.9-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()
  cpufreq / intel_pstate: Set timer timeout correctly
2013-04-11 20:33:38 -07:00
John Stultz
4e8f8b34b9 timekeeping: Make sure to notify hrtimers when TAI offset changes
Now that we have CLOCK_TAI timers, make sure we notify hrtimer
code when TAI offset is changed.

Signed-off-by: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/1365622909-953-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-11 10:19:44 +02:00
Linus Torvalds
9baba6660b Namhyung Kim fixed a long standing bug that can cause a kernel panic.
If the function profiler fails to allocate memory for everything,
 it will do a double free on the same pointer which can cause a panic.
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Merge tag 'trace-fixes-3.9-rc-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fix from Steven Rostedt:
 "Namhyung Kim fixed a long standing bug that can cause a kernel panic.

  If the function profiler fails to allocate memory for everything, it
  will do a double free on the same pointer which can cause a panic"

* tag 'trace-fixes-3.9-rc-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix double free when function profile init failed
2013-04-10 15:56:57 -07:00
Tejun Heo
ef824fa129 perf: make perf_event cgroup hierarchical
perf_event is one of a couple remaining cgroup controllers with broken
hierarchy support.  Converting it to support hierarchy is almost
trivial.  The only thing necessary is to consider a task belonging to
a descendant cgroup as a match.  IOW, if the cgroup of the currently
executing task (@cpuctx->cgrp) equals or is a descendant of the
event's cgroup (@event->cgrp), then the event should be enabled.

Implement hierarchy support and remove .broken_hierarchy tag along
with the incorrect comment on what needs to be done for hierarchy
support.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Stephane Eranian <eranian@google.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
2013-04-10 11:07:16 -07:00
Li Zefan
78574cf981 cgroup: implement cgroup_is_descendant()
A couple controllers want to determine whether two cgroups are in
ancestor/descendant relationship.  As it's more likely that the
descendant is the primary subject of interest and there are other
operations focusing on the descendants, let's ask is_descendent rather
than is_ancestor.

Implementation is trivial as the previous patch guarantees that all
ancestors of a cgroup stay accessible as long as the cgroup is
accessible.

tj: Removed depth optimization, renamed from cgroup_is_ancestor(),
    rewrote descriptions.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-10 11:07:08 -07:00
Li Zefan
415cf07a1c cgroup: make sure parent won't be destroyed before its children
Suppose we rmdir a cgroup and there're still css refs, this cgroup won't
be freed. Then we rmdir the parent cgroup, and the parent is freed
immediately due to css ref draining to 0. Now it would be a disaster if
the still-alive child cgroup tries to access its parent.

Make sure this won't happen.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-10 11:07:00 -07:00
Rami Rosen
84cfb6ab48 cgroup: remove bind() method from cgroup_subsys.
The bind() method of cgroup_subsys is not used in any of the
controllers (cpuset, freezer, blkio, net_cls, memcg, net_prio,
devices, perf, hugetlb, cpu and cpuacct)

tj: Removed the entry on ->bind() from
    Documentation/cgroups/cgroups.txt.  Also updated a couple
    paragraphs which were suggesting that dynamic re-binding may be
    implemented.  It's not gonna.

Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-10 10:46:59 -07:00
Ingo Molnar
b329fd5b01 sched/cpuacct/UML: Fix header file dependency bug on the UML build
The cpuacct split caused this build failure on UML:

  kernel/sched/cpuacct.c:94:2: error: implicit declaration of  function 'ERR_PTR'

Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 15:12:41 +02:00
Sasha Levin
8184004ed7 locking/rtmutex/tester: Set correct permissions on sysfs files
sysfs started complaining about cases where permissions don't
match what's in the sysfs ops structure (such as allowing read
without a "show" callback).

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: williams@redhat.com
Link: http://lkml.kernel.org/r/1363795105-5884-1-git-send-email-sasha.levin@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 14:48:37 +02:00
Li Zefan
479f614110 cgroup: Kill subsys.active flag
The only user was cpuacct.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155385A.4040207@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:22 +02:00
Li Zefan
a2b0ae25fc sched/cpuacct: No need to check subsys active state
Now we're guaranteed when cpuacct_charge() and
cpuacct_account_field() are called, cpuacct has already been
properly initialized, so we no longer need those checks.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155384C.7000508@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:22 +02:00
Li Zefan
621e2de024 sched/cpuacct: Initialize cpuacct subsystem earlier
Initialize cpuacct before the scheduler is functioning, so when
cpuacct_charge() and cpuacct_account_field() are called,
task_ca() won't return NULL.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155383F.8000005@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:21 +02:00
Li Zefan
14c6d3c8a4 sched/cpuacct: Initialize root cpuacct earlier
Now we don't need cpuacct_init(), and instead we just initialize
root_cpuacct when it's defined.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553834.9090701@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:20 +02:00
Li Zefan
7943e15a3e sched/cpuacct: Allocate per_cpu cpuusage for root cpuacct statically
This is a preparation, so later we can initialize cpuacct
earlier.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553822.5000403@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:20 +02:00
Li Zefan
d1712796a8 sched/cpuacct: Clean up cpuacct.h
Now most of the code in cpuacct.h can be moved to cpuacct.c

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536D5.2080401@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:19 +02:00
Li Zefan
5f40d80432 sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field()
This is a micro optimazation for a hot path.

- We don't need to check if @ca returned from task_ca() is NULL.
- We don't need to check if @ca returned from parent_ca() is NULL.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536B7.6060602@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:18 +02:00
Li Zefan
543bc0e76e sched/cpuacct: Remove redundant NULL checks in cpuacct_charge()
This is a micro optimization for the hot path.

- We don't need to check if @ca is NULL in parent_ca().
- We don't need to check if @ca is NULL in the beginning of the for loop.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/515536A9.5000700@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:18 +02:00
Li Zefan
1966aaf7d5 sched/cpuacct: Add cpuacct_acount_field()
So we can remove open-coded cpuacct code in cputime.c.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553692.9060008@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:17 +02:00
Li Zefan
dbe4b41f98 sched/cpuacct: Add cpuacct_init()
So we don't open-coded initialization of cpuacct in core.c.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51553687.1060906@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:16 +02:00
Li Zefan
60fed7891d sched: Split cpuacct code out of sched.h
Add cpuacct.h and let sched.h include it.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155367B.2060506@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:16 +02:00
Li Zefan
2e76c24d72 sched: Split cpuacct code out of core.c
Signed-off-by: Li Zefan <lizefan@huawei.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5155366F.5060404@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:54:15 +02:00
Libin
b9b0853a4b sched: Fix comment in rebalance_domains()
A comment in function rebalance_domains() mentions
arch_init_sched_domains(), but that function does not exist
anymore. The proper function is init_sched_domains().

Signed-off-by: Libin <huawei.libin@huawei.com>
Cc: <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1364814841-49156-1-git-send-email-huawei.libin@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 13:39:57 +02:00
Ingo Molnar
8fcfae3171 Merge branch 'rcu/next' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu
Pull RCU updates from Paul E. McKenney:

  * Remove restrictions on no-CBs CPUs, make RCU_FAST_NO_HZ
    take advantage of numbered callbacks, do additional callback
    accelerations based on numbered callbacks.  Posted to LKML
    at https://lkml.org/lkml/2013/3/18/960.

  * RCU documentation updates.  Posted to LKML at
    https://lkml.org/lkml/2013/3/18/570.

  * Miscellaneous fixes.  Posted to LKML at
    https://lkml.org/lkml/2013/3/18/594.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 12:55:49 +02:00
Zhang Hang
4e2dcb73ae sched: Simplify can_migrate_task()
At this point tsk_cache_hot is always true, so no need to check it.

Signed-off-by: Zhang Hang <bob.zhanghang@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51650107.9040606@huawei.com
[ Also remove unnecessary schedstat #ifdefs. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-10 11:15:45 +02:00
Namhyung Kim
39e30cd153 tracing: Fix off-by-one on allocating stat->pages
The first page was allocated separately, so no need to start from 0.

Link: http://lkml.kernel.org/r/1364820385-32027-2-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-09 19:00:49 -04:00
Namhyung Kim
83e03b3fe4 tracing: Fix double free when function profile init failed
On the failure path, stat->start and stat->pages will refer same page.
So it'll attempt to free the same page again and get kernel panic.

Link: http://lkml.kernel.org/r/1364820385-32027-1-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: stable@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-09 18:54:04 -04:00
Wei Yongjun
cece95dfe5 workqueue: use kmem_cache_free() instead of kfree()
memory allocated by kmem_cache_alloc() should be freed using
kmem_cache_free(), not kfree().

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-09 11:33:40 -07:00
Al Viro
fbd387aea0 create_proc_cpu_mask() doesn't need an argument...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-09 14:13:35 -04:00
Al Viro
d9dda78bad procfs: new helper - PDE_DATA(inode)
The only part of proc_dir_entry the code outside of fs/proc
really cares about is PDE(inode)->data.  Provide a helper
for that; static inline for now, eventually will be moved
to fs/proc, along with the knowledge of struct proc_dir_entry
layout.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-09 14:13:32 -04:00
Al Viro
4b8a8f1e4f get rid of the last free_pipe_info() callers
and rename __free_pipe_info() to free_pipe_info()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-09 14:13:02 -04:00
Al Viro
03d95eb2f2 lift sb_start_write() out of ->write()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-04-09 14:12:56 -04:00
Chen Gang
9607a869ee kernel: tracing: Use strlcpy instead of strncpy
Use strlcpy() instead of strncpy() as it will always add a '\0'
to the end of the string even if the buffer is smaller than what
is being copied.

Link: http://lkml.kernel.org/r/51624254.30301@asianux.com

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-09 11:25:08 -04:00
Linus Torvalds
5f2f280f87 This includes three fixes. Two fix features added in 3.9 and one
fixes a long time minor bug.
 
 The first patch fixes a race that can happen if the user switches
 from the irqsoff tracer to another tracer. If a irqs off latency is
 detected, it will try to use the snapshot buffer, but the new tracer
 wont have it allocated. There's a nasty warning that gets printed and
 the trace is ignored. Nothing crashes, just a nasty WARN_ON is shown.
 
 The second patch fixes an issue where if the sysctl is used to disable
 and enable function tracing, it can put the function tracing into an
 unstable state.
 
 The third patch fixes an issue with perf using the function tracer.
 An update was done, where the stub function could be called during
 the perf function tracing, and that stub function wont have the
 "control" flag set and cause a nasty warning when running perf.
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Merge tag 'trace-fixes-3.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing fixes from Steven Rostedt:
 "This includes three fixes.  Two fix features added in 3.9 and one
  fixes a long time minor bug.

  The first patch fixes a race that can happen if the user switches from
  the irqsoff tracer to another tracer.  If a irqs off latency is
  detected, it will try to use the snapshot buffer, but the new tracer
  wont have it allocated.  There's a nasty warning that gets printed and
  the trace is ignored.  Nothing crashes, just a nasty WARN_ON is shown.

  The second patch fixes an issue where if the sysctl is used to disable
  and enable function tracing, it can put the function tracing into an
  unstable state.

  The third patch fixes an issue with perf using the function tracer.
  An update was done, where the stub function could be called during the
  perf function tracing, and that stub function wont have the "control"
  flag set and cause a nasty warning when running perf."

* tag 'trace-fixes-3.9-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  ftrace: Do not call stub functions in control loop
  ftrace: Consistently restore trace function on sysctl enabling
  tracing: Fix race with update_max_tr_single and changing tracers
2013-04-08 15:14:11 -07:00
David Engraf
51fd36f3fa hrtimer: Fix ktime_add_ns() overflow on 32bit architectures
One can trigger an overflow when using ktime_add_ns() on a 32bit
architecture not supporting CONFIG_KTIME_SCALAR.

When passing a very high value for u64 nsec, e.g. 7881299347898368000
the do_div() function converts this value to seconds (7881299347) which
is still to high to pass to the ktime_set() function as long. The result
in is a negative value.

The problem on my system occurs in the tick-sched.c,
tick_nohz_stop_sched_tick() when time_delta is set to
timekeeping_max_deferment(). The check for time_delta < KTIME_MAX is
valid, thus ktime_add_ns() is called with a too large value resulting in
a negative expire value. This leads to an endless loop in the ticker code:

time_delta: 7881299347898368000
expires = ktime_add_ns(last_update, time_delta)
expires: negative value

This fix caps the value to KTIME_MAX.

This error doesn't occurs on 64bit or architectures supporting
CONFIG_KTIME_SCALAR (e.g. ARM, x86-32).

Cc: stable@vger.kernel.org
Signed-off-by: David Engraf <david.engraf@sysgo.com>
[jstultz: Minor tweaks to commit message & header]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-08 13:21:20 -07:00
Prarit Bhargava
8f294b5a13 hrtimer: Add expiry time overflow check in hrtimer_interrupt
The settimeofday01 test in the LTP testsuite effectively does

        gettimeofday(current time);
        settimeofday(Jan 1, 1970 + 100 seconds);
        settimeofday(current time);

This test causes a stack trace to be displayed on the console during the
setting of timeofday to Jan 1, 1970 + 100 seconds:

[  131.066751] ------------[ cut here ]------------
[  131.096448] WARNING: at kernel/time/clockevents.c:209 clockevents_program_event+0x135/0x140()
[  131.104935] Hardware name: Dinar
[  131.108150] Modules linked in: sg nfsv3 nfs_acl nfsv4 auth_rpcgss nfs dns_resolver fscache lockd sunrpc nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter ip_tables kvm_amd kvm sp5100_tco bnx2 i2c_piix4 crc32c_intel k10temp fam15h_power ghash_clmulni_intel amd64_edac_mod pcspkr serio_raw edac_mce_amd edac_core microcode xfs libcrc32c sr_mod sd_mod cdrom ata_generic crc_t10dif pata_acpi radeon i2c_algo_bit drm_kms_helper ttm drm ahci pata_atiixp libahci libata usb_storage i2c_core dm_mirror dm_region_hash dm_log dm_mod
[  131.176784] Pid: 0, comm: swapper/28 Not tainted 3.8.0+ #6
[  131.182248] Call Trace:
[  131.184684]  <IRQ>  [<ffffffff810612af>] warn_slowpath_common+0x7f/0xc0
[  131.191312]  [<ffffffff8106130a>] warn_slowpath_null+0x1a/0x20
[  131.197131]  [<ffffffff810b9fd5>] clockevents_program_event+0x135/0x140
[  131.203721]  [<ffffffff810bb584>] tick_program_event+0x24/0x30
[  131.209534]  [<ffffffff81089ab1>] hrtimer_interrupt+0x131/0x230
[  131.215437]  [<ffffffff814b9600>] ? cpufreq_p4_target+0x130/0x130
[  131.221509]  [<ffffffff81619119>] smp_apic_timer_interrupt+0x69/0x99
[  131.227839]  [<ffffffff8161805d>] apic_timer_interrupt+0x6d/0x80
[  131.233816]  <EOI>  [<ffffffff81099745>] ? sched_clock_cpu+0xc5/0x120
[  131.240267]  [<ffffffff814b9ff0>] ? cpuidle_wrap_enter+0x50/0xa0
[  131.246252]  [<ffffffff814b9fe9>] ? cpuidle_wrap_enter+0x49/0xa0
[  131.252238]  [<ffffffff814ba050>] cpuidle_enter_tk+0x10/0x20
[  131.257877]  [<ffffffff814b9c89>] cpuidle_idle_call+0xa9/0x260
[  131.263692]  [<ffffffff8101c42f>] cpu_idle+0xaf/0x120
[  131.268727]  [<ffffffff815f8971>] start_secondary+0x255/0x257
[  131.274449] ---[ end trace 1151a50552231615 ]---

When we change the system time to a low value like this, the value of
timekeeper->offs_real will be a negative value.

It seems that the WARN occurs because an hrtimer has been started in the time
between the releasing of the timekeeper lock and the IPI call (via a call to
on_each_cpu) in clock_was_set() in the do_settimeofday() code.  The end result
is that a REALTIME_CLOCK timer has been added with softexpires = expires =
KTIME_MAX.  The hrtimer_interrupt() fires/is called and the loop at
kernel/hrtimer.c:1289 is executed.  In this loop the code subtracts the
clock base's offset (which was set to timekeeper->offs_real in
do_settimeofday()) from the current hrtimer_cpu_base->expiry value (which
was KTIME_MAX):

	KTIME_MAX - (a negative value) = overflow

A simple check for an overflow can resolve this problem.  Using KTIME_MAX
instead of the overflow value will result in the hrtimer function being run,
and the reprogramming of the timer after that.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
[jstultz: Tweaked commit subject]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-08 13:20:44 -07:00
Huacai Chen
6f389a8f1d PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()
As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core
subsystems PM) say, syscore_ops operations should be carried with one
CPU on-line and interrupts disabled. However, after commit f96972f2d
(kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()),
syscore_shutdown() is called before disable_nonboot_cpus(), so break
the rules. We have a MIPS machine with a 8259A PIC, and there is an
external timer (HPET) linked at 8259A. Since 8259A has been shutdown
too early (by syscore_shutdown()), disable_nonboot_cpus() runs without
timer interrupt, so it hangs and reboot fails. This patch call
syscore_shutdown() a little later (after disable_nonboot_cpus()) to
avoid reboot failure, this is the same way as poweroff does.

For consistency, add disable_nonboot_cpus() to kernel_halt().

Signed-off-by: Huacai Chen <chenhc@lemote.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-08 22:10:40 +02:00
Steven Rostedt (Red Hat)
395b97a3ae ftrace: Do not call stub functions in control loop
The function tracing control loop used by perf spits out a warning
if the called function is not a control function. This is because
the control function references a per cpu allocated data structure
on struct ftrace_ops that is not allocated for other types of
functions.

commit 0a016409e4 "ftrace: Optimize the function tracer list loop"

Had an optimization done to all function tracing loops to optimize
for a single registered ops. Unfortunately, this allows for a slight
race when tracing starts or ends, where the stub function might be
called after the current registered ops is removed. In this case we
get the following dump:

root# perf stat -e ftrace:function sleep 1
[   74.339105] WARNING: at include/linux/ftrace.h:209 ftrace_ops_control_func+0xde/0xf0()
[   74.349522] Hardware name: PRIMERGY RX200 S6
[   74.357149] Modules linked in: sg igb iTCO_wdt ptp pps_core iTCO_vendor_support i7core_edac dca lpc_ich i2c_i801 coretemp edac_core crc32c_intel mfd_core ghash_clmulni_intel dm_multipath acpi_power_meter pcspk
r microcode vhost_net tun macvtap macvlan nfsd kvm_intel kvm auth_rpcgss nfs_acl lockd sunrpc uinput xfs libcrc32c sd_mod crc_t10dif sr_mod cdrom mgag200 i2c_algo_bit drm_kms_helper ttm qla2xxx mptsas ahci drm li
bahci scsi_transport_sas mptscsih libata scsi_transport_fc i2c_core mptbase scsi_tgt dm_mirror dm_region_hash dm_log dm_mod
[   74.446233] Pid: 1377, comm: perf Tainted: G        W    3.9.0-rc1 #1
[   74.453458] Call Trace:
[   74.456233]  [<ffffffff81062e3f>] warn_slowpath_common+0x7f/0xc0
[   74.462997]  [<ffffffff810fbc60>] ? rcu_note_context_switch+0xa0/0xa0
[   74.470272]  [<ffffffff811041a2>] ? __unregister_ftrace_function+0xa2/0x1a0
[   74.478117]  [<ffffffff81062e9a>] warn_slowpath_null+0x1a/0x20
[   74.484681]  [<ffffffff81102ede>] ftrace_ops_control_func+0xde/0xf0
[   74.491760]  [<ffffffff8162f400>] ftrace_call+0x5/0x2f
[   74.497511]  [<ffffffff8162f400>] ? ftrace_call+0x5/0x2f
[   74.503486]  [<ffffffff8162f400>] ? ftrace_call+0x5/0x2f
[   74.509500]  [<ffffffff810fbc65>] ? synchronize_sched+0x5/0x50
[   74.516088]  [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[   74.522268]  [<ffffffff810fbc65>] ? synchronize_sched+0x5/0x50
[   74.528837]  [<ffffffff811041a2>] ? __unregister_ftrace_function+0xa2/0x1a0
[   74.536696]  [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[   74.542878]  [<ffffffff8162402d>] ? mutex_lock+0x1d/0x50
[   74.548869]  [<ffffffff81105c67>] unregister_ftrace_function+0x27/0x50
[   74.556243]  [<ffffffff8111eadf>] perf_ftrace_event_register+0x9f/0x140
[   74.563709]  [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[   74.569887]  [<ffffffff8162402d>] ? mutex_lock+0x1d/0x50
[   74.575898]  [<ffffffff8111e94e>] perf_trace_destroy+0x2e/0x50
[   74.582505]  [<ffffffff81127ba9>] tp_perf_event_destroy+0x9/0x10
[   74.589298]  [<ffffffff811295d0>] free_event+0x70/0x1a0
[   74.595208]  [<ffffffff8112a579>] perf_event_release_kernel+0x69/0xa0
[   74.602460]  [<ffffffff816254d5>] ? _cond_resched+0x5/0x40
[   74.608667]  [<ffffffff8112a640>] put_event+0x90/0xc0
[   74.614373]  [<ffffffff8112a740>] perf_release+0x10/0x20
[   74.620367]  [<ffffffff811a3044>] __fput+0xf4/0x280
[   74.625894]  [<ffffffff811a31de>] ____fput+0xe/0x10
[   74.631387]  [<ffffffff81083697>] task_work_run+0xa7/0xe0
[   74.637452]  [<ffffffff81014981>] do_notify_resume+0x71/0xb0
[   74.643843]  [<ffffffff8162fa92>] int_signal+0x12/0x17

To fix this a new ftrace_ops flag is added that denotes the ftrace_list_end
ftrace_ops stub as just that, a stub. This flag is now checked in the
control loop and the function is not called if the flag is set.

Thanks to Jovi for not just reporting the bug, but also pointing out
where the bug was in the code.

Link: http://lkml.kernel.org/r/514A8855.7090402@redhat.com
Link: http://lkml.kernel.org/r/1364377499-1900-15-git-send-email-jovi.zhangwei@huawei.com

Tested-by: WANG Chao <chaowang@redhat.com>
Reported-by: WANG Chao <chaowang@redhat.com>
Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-08 12:24:23 -04:00
Jan Kiszka
5000c41884 ftrace: Consistently restore trace function on sysctl enabling
If we reenable ftrace via syctl, we currently set ftrace_trace_function
based on the previous simplistic algorithm. This is inconsistent with
what update_ftrace_function does. So better call that helper instead.

Link: http://lkml.kernel.org/r/5151D26F.1070702@siemens.com

Cc: stable@vger.kernel.org
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-08 12:24:22 -04:00
Steven Rostedt (Red Hat)
2930e04d00 tracing: Fix race with update_max_tr_single and changing tracers
The commit 34600f0e9 "tracing: Fix race with max_tr and changing tracers"
fixed the updating of the main buffers with the race of changing
tracers, but left out the fix to the updating of just a per cpu buffer.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-04-08 12:24:22 -04:00
Stanislaw Gruszka
e614b3332a sched/cputime: Fix accounting on multi-threaded processes
Recent commit 6fac4829 ("cputime: Use accessors to read task
cputime stats") introduced a bug, where we account many times
the cputime of the first thread, instead of cputimes of all
the different threads.

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130404085740.GA2495@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 17:40:52 +02:00
Hong Zhiguo
bfaf4af8ab lockdep: Remove unnecessary 'hlock_next' variable
Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1365058881-4044-1-git-send-email-honkiko@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 17:39:34 +02:00
Thomas Gleixner
d166991234 idle: Implement generic idle function
All idle functions in arch/* are more or less the same, plus minus a
few bugs and extra instrumentation, tickless support and other
optional items.

Implement a generic idle function which resembles the functionality
found in arch/. Provide weak arch_cpu_idle_* functions which can be
overridden by the architecture code if needed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.646635455@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-08 17:39:23 +02:00
Thomas Gleixner
a1a04ec3c7 idle: Provide a generic entry point for the idle code
For now this calls cpu_idle(), but in the long run we want to move the
cpu bringup code to the core and therefor we add a state argument.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.583190032@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-08 17:39:23 +02:00
Thomas Gleixner
ee761f629d arch: Consolidate tsk_is_polling()
Move it to a common place. Preparatory patch for implementing
set/clear for the idle need_resched poll implementation.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Link: http://lkml.kernel.org/r/20130321215233.446034505@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-04-08 17:39:22 +02:00
Viresh Kumar
28b4a521f6 sched: Fix typo inside comment
Fix typo:

 sched_domains_nume_distance ->
 sched_domains_numa_distance

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: linaro-kernel@lists.linaro.org
Cc: patches@linaro.org
Cc: robin.randhawa@arm.com
Cc: Steve.Bannister@arm.com
Cc: Liviu.Dudau@arm.com
Cc: charles.garcia-tobin@arm.com
Cc: arvind.chauhan@arm.com
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/cd8084746ac932106d6fa6be388b8f2d6aa9617c.1365159023.git.viresh.kumar@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 13:55:39 +02:00
Chen Gang
75761cc158 ftrace: Fix strncpy() use, use strlcpy() instead of strncpy()
For NUL terminated string we always need to set '\0' at the end.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/516243B7.9020405@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 13:26:56 +02:00
Chen Gang
67012ab1d2 perf: Fix strncpy() use, use strlcpy() instead of strncpy()
For NUL terminated string we always need to set '\0' at the end.

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: rostedt@goodmis.org
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Link: http://lkml.kernel.org/r/51624254.30301@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 13:26:56 +02:00
Chen Gang
c97847d2f0 perf: Fix strncpy() use, always make sure it's NUL terminated
For NUL terminated string, always make sure that there's '\0' at the end.

In our case we need a return value, so still use strncpy() and
fix up the tail explicitly.

(strlcpy() returns the size, not the pointer)

Signed-off-by: Chen Gang <gang.chen@asianux.com>
Cc: a.p.zijlstra@chello.nl <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org <paulus@samba.org>
Cc: acme@ghostprotocols.net <acme@ghostprotocols.net>
Link: http://lkml.kernel.org/r/51623E0B.7070101@asianux.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 13:26:55 +02:00
libin
fd9b86d37a sched/debug: Fix sd->*_idx limit range avoiding overflow
Commit 201c373e8e ("sched/debug: Limit sd->*_idx range on
sysctl") was an incomplete bug fix.

This patch fixes sd->*_idx limit range to [0 ~ CPU_LOAD_IDX_MAX-1]
avoiding array overflow caused by setting sd->*_idx to CPU_LOAD_IDX_MAX
on sysctl.

Signed-off-by: Libin <huawei.libin@huawei.com>
Cc: <jiang.liu@huawei.com>
Cc: <guohanjun@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/51626610.2040607@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 13:23:03 +02:00
Thomas Gleixner
a1cbcaa9ea sched_clock: Prevent 64bit inatomicity on 32bit systems
The sched_clock_remote() implementation has the following inatomicity
problem on 32bit systems when accessing the remote scd->clock, which
is a 64bit value.

CPU0			CPU1

sched_clock_local()	sched_clock_remote(CPU0)
...
			remote_clock = scd[CPU0]->clock
			    read_low32bit(scd[CPU0]->clock)
cmpxchg64(scd->clock,...)
			    read_high32bit(scd[CPU0]->clock)

While the update of scd->clock is using an atomic64 mechanism, the
readout on the remote cpu is not, which can cause completely bogus
readouts.

It is a quite rare problem, because it requires the update to hit the
narrow race window between the low/high readout and the update must go
across the 32bit boundary.

The resulting misbehaviour is, that CPU1 will see the sched_clock on
CPU1 ~4 seconds ahead of it's own and update CPU1s sched_clock value
to this bogus timestamp. This stays that way due to the clamping
implementation for about 4 seconds until the synchronization with
CLOCK_MONOTONIC undoes the problem.

The issue is hard to observe, because it might only result in a less
accurate SCHED_OTHER timeslicing behaviour. To create observable
damage on realtime scheduling classes, it is necessary that the bogus
update of CPU1 sched_clock happens in the context of an realtime
thread, which then gets charged 4 seconds of RT runtime, which results
in the RT throttler mechanism to trigger and prevent scheduling of RT
tasks for a little less than 4 seconds. So this is quite unlikely as
well.

The issue was quite hard to decode as the reproduction time is between
2 days and 3 weeks and intrusive tracing makes it less likely, but the
following trace recorded with trace_clock=global, which uses
sched_clock_local(), gave the final hint:

  <idle>-0   0d..30 400269.477150: hrtimer_cancel: hrtimer=0xf7061e80
  <idle>-0   0d..30 400269.477151: hrtimer_start:  hrtimer=0xf7061e80 ...
irq/20-S-587 1d..32 400273.772118: sched_wakeup:   comm= ... target_cpu=0
  <idle>-0   0dN.30 400273.772118: hrtimer_cancel: hrtimer=0xf7061e80

What happens is that CPU0 goes idle and invokes
sched_clock_idle_sleep_event() which invokes sched_clock_local() and
CPU1 runs a remote wakeup for CPU0 at the same time, which invokes
sched_remote_clock(). The time jump gets propagated to CPU0 via
sched_remote_clock() and stays stale on both cores for ~4 seconds.

There are only two other possibilities, which could cause a stale
sched clock:

1) ktime_get() which reads out CLOCK_MONOTONIC returns a sporadic
   wrong value.

2) sched_clock() which reads the TSC returns a sporadic wrong value.

#1 can be excluded because sched_clock would continue to increase for
   one jiffy and then go stale.

#2 can be excluded because it would not make the clock jump
   forward. It would just result in a stale sched_clock for one jiffy.

After quite some brain twisting and finding the same pattern on other
traces, sched_clock_remote() remained the only place which could cause
such a problem and as explained above it's indeed racy on 32bit
systems.

So while on 64bit systems the readout is atomic, we need to verify the
remote readout on 32bit machines. We need to protect the local->clock
readout in sched_clock_remote() on 32bit as well because an NMI could
hit between the low and the high readout, call sched_clock_local() and
modify local->clock.

Thanks to Siegfried Wulsch for bearing with my debug requests and
going through the tedious tasks of running a bunch of reproducer
systems to generate the debug information which let me decode the
issue.

Reported-by: Siegfried Wulsch <Siegfried.Wulsch@rovema.de>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1304051544160.21884@ionos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
2013-04-08 11:50:44 +02:00
Ingo Molnar
529801898b Merge branch 'for-tip' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile into perf/core
Pull IBM zEnterprise EC12 support patchlet from Robert Richter.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-08 11:43:30 +02:00
Tejun Heo
2219449a65 cgroup: remove cgroup_lock_is_held()
We don't want controllers to assume that the information is officially
available and do funky things with it.

The only user is task_subsys_state_check() which uses it to verify RCU
access context.  We can move cgroup_lock_is_held() inside
CONFIG_PROVE_RCU but that doesn't add meaningful protection compared
to conditionally exposing cgroup_mutex.

Remove cgroup_lock_is_held(), export cgroup_mutex iff CONFIG_PROVE_RCU
and use lockdep_is_held() directly on the mutex in
task_subsys_state_check().

While at it, add parentheses around macro arguments in
task_subsys_state_check().

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2013-04-07 09:29:51 -07:00
Tejun Heo
47cfcd0922 cgroup: kill cgroup_[un]lock()
Now that locking interface is unexported, there's no reason to keep
around these thin wrappers.  Kill them and use mutex operations
directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2013-04-07 09:29:51 -07:00
Tejun Heo
b9777cf8d7 cgroup: unexport locking interface and cgroup_attach_task()
Now that all external cgroup_lock() users are gone, we can finally
unexport the locking interface and prevent future abuse of
cgroup_mutex.

Make cgroup_[un]lock() and cgroup_lock_live_group() static.  Also,
cgroup_attach_task() doesn't have any user left and can't be used
without locking interface anyway.  Make it static too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2013-04-07 09:29:51 -07:00
Tejun Heo
7ae1bad99e cgroup: relocate cgroup_lock_live_group() and cgroup_attach_task_all()
cgroup_lock_live_group() and cgroup_attach_task() are scheduled to be
made static.  Relocate the former and cgroup_attach_task_all() so that
we don't need forward declarations.

This patch is pure relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2013-04-07 09:29:51 -07:00
Tejun Heo
8cc9934520 cgroup, cpuset: replace move_member_tasks_to_cpuset() with cgroup_transfer_tasks()
When a cpuset becomes empty (no CPU or memory), its tasks are
transferred with the nearest ancestor with execution resources.  This
is implemented using cgroup_scan_tasks() with a callback which grabs
cgroup_mutex and invokes cgroup_attach_task() on each task.

Both cgroup_mutex and cgroup_attach_task() are scheduled to be
unexported.  Implement cgroup_transfer_tasks() in cgroup proper which
is essentially the same as move_member_tasks_to_cpuset() except that
it takes cgroups instead of cpusets and @to comes before @from like
normal functions with those arguments, and replace
move_member_tasks_to_cpuset() with it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
2013-04-07 09:29:50 -07:00
Zhang Rui
c26b78a2d8 PM / sleep: invalidate TEST_CPUS and TEST_CORE support for freeze state
freeze state is a software suspend state that does not run into
low-level platform callbacks which may interact with BIOS.
And freeze state does not need to disable the processors.

But the current pm_test support misleads users because users
can enter freeze state with pm_test set to TEST_CPUS/TEST_CORE,
while this pm_test setting never takes actions.

So, invalidate TEST_CPUS/TEST_CORE for freeze state in this patch.
Then users will get an error instead, when trying to
enter freeze state with pm_test mode set to TEST_CPUS/TEST_CORE.

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-05 14:18:25 +02:00
Zhang Rui
08605acc7e PM / sleep: add TEST_PLATFORM support for freeze state
Invoke freeze_enter() after suspend_test(TEST_PLATFORM) being invoked.

So when setting /sys/power/pm_test to "platform", it can be used to
check if freeze state is working well after all devices are suspended
and before processors are blocked,

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-04-05 14:18:25 +02:00
Dave Airlie
399403c7ce Merge tag 'drm-intel-next-2013-03-23' of git://people.freedesktop.org/~danvet/drm-intel into drm-next
Daniel writes:
Highlights:
- Imre's for_each_sg_pages rework (now also with the stolen mem backed
  case fixed with a hack) plus the drm prime sg list coalescing patch from
  Rahul Sharma. I have some follow-up cleanups pending, already acked by
  Andrew Morton.
- Some prep-work for the crazy no-pch/display-less platform by Ben.
- Some vlv patches, by far not all (Jesse et al).
- Clean up the HDMI/SDVO #define confusion (Paulo)
- gen2-4 vblank fixes from Ville.
- Unclaimed register warning fixes for hsw (Paulo). More still to come ...
- Complete pageflips which have been stuck in a gpu hang, should prevent
  stuck gl compositors (Ville).
- pm patches for vt-switchless resume (Jesse). Note that the i915 enabling
  is not (yet) included, that took a bit longer to settle. PM patches are
  acked by Rafael Wysocki.
- Minor fixlets all over from various people.

* tag 'drm-intel-next-2013-03-23' of git://people.freedesktop.org/~danvet/drm-intel: (79 commits)
  drm/i915: Implement WaSwitchSolVfFArbitrationPriority
  drm/i915: Set the VIC in AVI infoframe for SDVO
  drm/i915: Kill a strange comment about DPMS functions
  drm/i915: Correct sandybrige overclocking
  drm/i915: Introduce GEN7_FEATURES for device info
  drm/i915: Move num_pipes to intel info
  drm/i915: fixup pd vs pt confusion in gen6 ppgtt code
  style nit: Align function parameter continuation properly.
  drm/i915: VLV doesn't have HDMI on port C
  drm/i915: DSPFW and BLC regs are in the display offset range
  drm/i915: set conservative clock gating values on VLV v2
  drm/i915: fix WaDisablePSDDualDispatchEnable on VLV v2
  drm/i915: add more VLV IDs
  drm/i915: use VLV DIP routines on VLV v2
  drm/i915: add media well to VLV force wake routines v2
  drm/i915: don't use plane pipe select on VLV
  drm: modify pages_to_sg prime helper to create optimized SG table
  drm/i915: use for_each_sg_page for setting up the gtt ptes
  drm/i915: create compact dma scatter lists for gem objects
  drm/i915: handle walking compact dma scatter lists
  ...
2013-04-05 10:18:13 +10:00
Thomas Gleixner
ca4523cda4 timekeeping: Shorten seq_count region
Shorten the seqcount write hold region to the actual update of the
timekeeper and the related data (e.g vsyscall).

On a contemporary x86 system this reduces the maximum latencies on
Preempt-RT from 8us to 4us on the non-timekeeping cores.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:32 -07:00
Thomas Gleixner
48cdc135d4 timekeeping: Implement a shadow timekeeper
Use the shadow timekeeper to do the update_wall_time() adjustments and
then copy it over to the real timekeeper.

Keep the shadow timekeeper in sync when updating stuff outside of
update_wall_time().

This allows us to limit the timekeeper_seq hold time to the update of
the real timekeeper and the vsyscall data in the next patch.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:32 -07:00
Thomas Gleixner
7ec98e15aa timekeeping: Delay update of clock->cycle_last
For calculating the new timekeeper values store the new cycle_last
value in the timekeeper and update the clock->cycle_last just when we
actually update the new values.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:31 -07:00
Thomas Gleixner
14a3b6abe9 timekeeping: Store cycle_last value in timekeeper struct as well
For implementing a shadow timekeeper and a split calculation/update
region we need to store the cycle_last value in the timekeeper and
update the value in the clocksource struct only in the update region.

Add the extra storage to the timekeeper.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:31 -07:00
John Stultz
a076b2146f ntp: Remove ntp_lock, using the timekeeping locks to protect ntp state
In order to properly handle the NTP state in future changes to the
timekeeping lock management, this patch moves the management of
all of the ntp state under the timekeeping locks.

This allows us to remove the ntp_lock.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:17 -07:00
John Stultz
0b5154fb90 timekeeping: Simplify tai updating from do_adjtimex
Since we are taking the timekeeping locks, just go ahead
and update any tai change directly, rather then dropping
the lock and calling a function that will just take it again.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:16 -07:00
John Stultz
06c017fdd4 timekeeping: Hold timekeepering locks in do_adjtimex and hardpps
In moving the NTP state to be protected by the timekeeping locks,
be sure to acquire the timekeeping locks prior to calling
ntp functions.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:16 -07:00
John Stultz
cef90377fa timekeeping: Move ADJ_SETOFFSET to top level do_adjtimex()
Since ADJ_SETOFFSET adjusts the timekeeping state, process
it as part of the top level do_adjtimex() function in
timekeeping.c.

This avoids deadlocks that could occur once we change the
ntp locking rules.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:15 -07:00
John Stultz
87ace39b71 ntp: Rework do_adjtimex to take timespec and tai arguments
In order to change the locking rules, we need to provide
the timespec and tai values rather then having the ntp
logic acquire these values itself.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:15 -07:00
John Stultz
e4085693f6 ntp: Move timex validation to timekeeping do_adjtimex call.
Move logic that does not need the ntp state to be done
in the timekeeping do_adjtimex() call.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:14 -07:00
John Stultz
aa6f9c595d ntp: Move do_adjtimex() and hardpps() functions to timekeeping.c
In preparation for changing the ntp locking rules, move
do_adjtimex and hardpps accessor functions to timekeeping.c,
but keep the code logic in ntp.c.

This patch also introduces a ntp_internal.h file so timekeeping
specific interfaces of ntp.c can be more limitedly shared with
timekeeping.c.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:14 -07:00
John Stultz
ad460967a2 ntp: Split out timex validation from do_adjtimex
Split out the timex validation done in do_adjtimex into a separate
function. This will help simplify logic in following patches.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-04-04 13:18:14 -07:00
Lai Jiangshan
5c529597e9 workqueue: avoid false negative WARN_ON() in destroy_workqueue()
destroy_workqueue() performs several sanity checks before proceeding
with destruction of a workqueue.  One of the checks verifies that
refcnt of each pwq (pool_workqueue) is over 1 as at that point there
should be no in-flight work items and the only holder of pwq refs is
the workqueue itself.

This worked fine as a workqueue used to hold only one reference to its
pwqs; however, since 4c16bd327c ("workqueue: implement NUMA affinity
for unbound workqueues"), a workqueue may hold multiple references to
its default pwq triggering this sanity check spuriously.

Fix it by not triggering the pwq->refcnt assertion on default pwqs.

An example spurious WARN trigger follows.

 WARNING: at kernel/workqueue.c:4201 destroy_workqueue+0x6a/0x13e()
 Hardware name: 4286C12
 Modules linked in: sdhci_pci sdhci mmc_core usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video
 Pid: 361, comm: umount Not tainted 3.9.0-rc5+ #29
 Call Trace:
  [<c04314a7>] warn_slowpath_common+0x7c/0x93
  [<c04314e0>] warn_slowpath_null+0x22/0x24
  [<c044796a>] destroy_workqueue+0x6a/0x13e
  [<c056dc01>] ext4_put_super+0x43/0x2c4
  [<c04fb7b8>] generic_shutdown_super+0x4b/0xb9
  [<c04fb848>] kill_block_super+0x22/0x60
  [<c04fb960>] deactivate_locked_super+0x2f/0x56
  [<c04fc41b>] deactivate_super+0x2e/0x31
  [<c050f1e6>] mntput_no_expire+0x103/0x108
  [<c050fdce>] sys_umount+0x2a2/0x2c4
  [<c050fe0e>] sys_oldumount+0x1e/0x20
  [<c085ba4d>] sysenter_do_call+0x12/0x38

tj: Rewrote description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
2013-04-04 07:54:01 -07:00
Oleg Nesterov
3f47107c5c uprobes: Change write_opcode() to use copy_*page()
Change write_opcode() to use copy_highpage() + copy_to_page()
and simplify the code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:06 +02:00
Oleg Nesterov
5669ccee21 uprobes: Introduce copy_to_page()
Extract the kmap_atomic/memcpy/kunmap_atomic code from
xol_get_insn_slot() into the new simple helper, copy_to_page().
It will have more users soon.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:05 +02:00
Oleg Nesterov
98763a1bb1 uprobes: Kill the unnecesary filp != NULL check in __copy_insn()
__copy_insn(filp) can only be called after valid_vma() returns T,
vma->vm_file passed as "filp" can not be NULL.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:05 +02:00
Oleg Nesterov
2edb7b5574 uprobes: Change __copy_insn() to use copy_from_page()
Change __copy_insn() to use copy_from_page() and simplify the code.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:05 +02:00
Oleg Nesterov
ab0d805c7b uprobes: Turn copy_opcode() into copy_from_page()
No functional changes. Rename copy_opcode() into copy_from_page() and
add the new "int len" argument to make it more more generic for the
new users.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:04 +02:00
Ananth N Mavinakayanahalli
0908ad6e56 uprobes: Add trap variant helper
Some architectures like powerpc have multiple variants of the trap
instruction. Introduce an additional helper is_trap_insn() for run-time
handling of non-uprobe traps on such architectures.

While there, change is_swbp_at_addr() to is_trap_at_addr() for reading
clarity.

With this change, the uprobe registration path will supercede any trap
instruction inserted at the requested location, while taking care of
delivering the SIGTRAP for cases where the trap notification came in
for an address without a uprobe. See [1] for a more detailed explanation.

[1] https://lists.ozlabs.org/pipermail/linuxppc-dev/2013-March/104771.html

This change was suggested by Oleg Nesterov.

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
2013-04-04 13:57:04 +02:00
Oleg Nesterov
f281769e81 uprobes: Use file_inode()
Cleanup. Now that we have f_inode/file_inode() we can use it instead
of vm_file->f_mapping->host.

This should not make any difference for uprobes, but in theory this
change is more correct. We use this inode as a key, to compare it
with uprobe->inode set by uprobe_register(inode), and the caller uses
d_inode.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
2013-04-04 13:57:03 +02:00
Kevin Wilson
1e2ccd1c0f cgroup: remove unused parameter in cgroup_task_migrate().
This patch removes unused parameter from cgroup_task_migrate().

Signed-off-by: Kevin Wilson <wkevils@gmail.com>
Acked-by: Acked-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-03 14:04:33 -07:00
Thomas Gleixner
0ed2aef9b3 Merge branch 'fortglx/3.10/time' of git://git.linaro.org/people/jstultz/linux into timers/core 2013-04-03 12:27:29 +02:00
Tejun Heo
229641a6f1 Linux 3.9-rc5
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Merge tag 'v3.9-rc5' into wq/for-3.10

Writeback conversion to workqueue will be based on top of wq/for-3.10
branch to take advantage of custom attrs and NUMA support for unbound
workqueues.  Mainline currently contains two commits which result in
non-trivial merge conflicts with wq/for-3.10 and because
block/for-3.10/core is based on v3.9-rc3 which contains one of the
conflicting commits, we need a pre-merge-window merge anyway.  Let's
pull v3.9-rc5 into wq/for-3.10 so that the block tree doesn't suffer
from workqueue merge conflicts.

The two conflicts and their resolutions:

* e68035fb65 ("workqueue: convert to idr_alloc()") in mainline changes
  worker_pool_assign_id() to use idr_alloc() instead of the old idr
  interface.  worker_pool_assign_id() goes through multiple locking
  changes in wq/for-3.10 causing the following conflict.

  static int worker_pool_assign_id(struct worker_pool *pool)
  {
	  int ret;

  <<<<<<< HEAD
	  lockdep_assert_held(&wq_pool_mutex);

	  do {
		  if (!idr_pre_get(&worker_pool_idr, GFP_KERNEL))
			  return -ENOMEM;
		  ret = idr_get_new(&worker_pool_idr, pool, &pool->id);
	  } while (ret == -EAGAIN);
  =======
	  mutex_lock(&worker_pool_idr_mutex);
	  ret = idr_alloc(&worker_pool_idr, pool, 0, 0, GFP_KERNEL);
	  if (ret >= 0)
		  pool->id = ret;
	  mutex_unlock(&worker_pool_idr_mutex);
  >>>>>>> c67bf5361e

	  return ret < 0 ? ret : 0;
  }

  We want locking from the former and idr_alloc() usage from the
  latter, which can be combined to the following.

  static int worker_pool_assign_id(struct worker_pool *pool)
  {
	  int ret;

	  lockdep_assert_held(&wq_pool_mutex);

	  ret = idr_alloc(&worker_pool_idr, pool, 0, 0, GFP_KERNEL);
	  if (ret >= 0) {
		  pool->id = ret;
		  return 0;
	  }
	  return ret;
   }

* eb2834285c ("workqueue: fix possible pool stall bug in
  wq_unbind_fn()") updated wq_unbind_fn() such that it has single
  larger for_each_std_worker_pool() loop instead of two separate loops
  with a schedule() call inbetween.  wq/for-3.10 renamed
  pool->assoc_mutex to pool->manager_mutex causing the following
  conflict (earlier function body and comments omitted for brevity).

  static void wq_unbind_fn(struct work_struct *work)
  {
  ...
		  spin_unlock_irq(&pool->lock);
  <<<<<<< HEAD
		  mutex_unlock(&pool->manager_mutex);
	  }
  =======
		  mutex_unlock(&pool->assoc_mutex);
  >>>>>>> c67bf5361e

		  schedule();

  <<<<<<< HEAD
	  for_each_cpu_worker_pool(pool, cpu)
  =======
  >>>>>>> c67bf5361e
		  atomic_set(&pool->nr_running, 0);

		  spin_lock_irq(&pool->lock);
		  wake_up_worker(pool);
		  spin_unlock_irq(&pool->lock);
	  }
  }

  The resolution is mostly trivial.  We want the control flow of the
  latter with the rename of the former.

  static void wq_unbind_fn(struct work_struct *work)
  {
  ...
		  spin_unlock_irq(&pool->lock);
		  mutex_unlock(&pool->manager_mutex);

		  schedule();

		  atomic_set(&pool->nr_running, 0);

		  spin_lock_irq(&pool->lock);
		  wake_up_worker(pool);
		  spin_unlock_irq(&pool->lock);
	  }
  }

Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-01 18:45:36 -07:00
Tejun Heo
d55262c4d1 workqueue: update sysfs interface to reflect NUMA awareness and a kernel param to disable NUMA affinity
Unbound workqueues are now NUMA aware.  Let's add some control knobs
and update sysfs interface accordingly.

* Add kernel param workqueue.numa_disable which disables NUMA affinity
  globally.

* Replace sysfs file "pool_id" with "pool_ids" which contain
  node:pool_id pairs.  This change is userland-visible but "pool_id"
  hasn't seen a release yet, so this is okay.

* Add a new sysf files "numa" which can toggle NUMA affinity on
  individual workqueues.  This is implemented as attrs->no_numa whichn
  is special in that it isn't part of a pool's attributes.  It only
  affects how apply_workqueue_attrs() picks which pools to use.

After "pool_ids" change, first_pwq() doesn't have any user left.
Removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:38 -07:00
Tejun Heo
4c16bd327c workqueue: implement NUMA affinity for unbound workqueues
Currently, an unbound workqueue has single current, or first, pwq
(pool_workqueue) to which all new work items are queued.  This often
isn't optimal on NUMA machines as workers may jump around across node
boundaries and work items get assigned to workers without any regard
to NUMA affinity.

This patch implements NUMA affinity for unbound workqueues.  Instead
of mapping all entries of numa_pwq_tbl[] to the same pwq,
apply_workqueue_attrs() now creates a separate pwq covering the
intersecting CPUs for each NUMA node which has online CPUs in
@attrs->cpumask.  Nodes which don't have intersecting possible CPUs
are mapped to pwqs covering whole @attrs->cpumask.

As CPUs come up and go down, the pool association is changed
accordingly.  Changing pool association may involve allocating new
pools which may fail.  To avoid failing CPU_DOWN, each workqueue
always keeps a default pwq which covers whole attrs->cpumask which is
used as fallback if pool creation fails during a CPU hotplug
operation.

This ensures that all work items issued on a NUMA node is executed on
the same node as long as the workqueue allows execution on the CPUs of
the node.

As this maps a workqueue to multiple pwqs and max_active is per-pwq,
this change the behavior of max_active.  The limit is now per NUMA
node instead of global.  While this is an actual change, max_active is
already per-cpu for per-cpu workqueues and primarily used as safety
mechanism rather than for active concurrency control.  Concurrency is
usually limited from workqueue users by the number of concurrently
active work items and this change shouldn't matter much.

v2: Fixed pwq freeing in apply_workqueue_attrs() error path.  Spotted
    by Lai.

v3: The previous version incorrectly made a workqueue spanning
    multiple nodes spread work items over all online CPUs when some of
    its nodes don't have any desired cpus.  Reimplemented so that NUMA
    affinity is properly updated as CPUs go up and down.  This problem
    was spotted by Lai Jiangshan.

v4: destroy_workqueue() was putting wq->dfl_pwq and then clearing it;
    however, wq may be freed at any time after dfl_pwq is put making
    the clearing use-after-free.  Clear wq->dfl_pwq before putting it.

v5: apply_workqueue_attrs() was leaking @tmp_attrs, @new_attrs and
    @pwq_tbl after success.  Fixed.

    Retry loop in wq_update_unbound_numa_attrs() isn't necessary as
    application of new attrs is excluded via CPU hotplug.  Removed.

    Documentation on CPU affinity guarantee on CPU_DOWN added.

    All changes are suggested by Lai Jiangshan.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:36 -07:00
Tejun Heo
dce90d47c4 workqueue: introduce put_pwq_unlocked()
Factor out lock pool, put_pwq(), unlock sequence into
put_pwq_unlocked().  The two existing places are converted and there
will be more with NUMA affinity support.

This is to prepare for NUMA affinity support for unbound workqueues
and doesn't introduce any functional difference.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
1befcf3073 workqueue: introduce numa_pwq_tbl_install()
Factor out pool_workqueue linking and installation into numa_pwq_tbl[]
from apply_workqueue_attrs() into numa_pwq_tbl_install().  link_pwq()
is made safe to call multiple times.  numa_pwq_tbl_install() links the
pwq, installs it into numa_pwq_tbl[] at the specified node and returns
the old entry.

@last_pwq is removed from link_pwq() as the return value of the new
function can be used instead.

This is to prepare for NUMA affinity support for unbound workqueues.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
e50aba9aea workqueue: use NUMA-aware allocation for pool_workqueues
Use kmem_cache_alloc_node() with @pool->node instead of
kmem_cache_zalloc() when allocating a pool_workqueue so that it's
allocated on the same node as the associated worker_pool.  As there's
no no kmem_cache_zalloc_node(), move zeroing to init_pwq().

This was suggested by Lai Jiangshan.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
f147f29eb7 workqueue: break init_and_link_pwq() into two functions and introduce alloc_unbound_pwq()
Break init_and_link_pwq() into init_pwq() and link_pwq() and move
unbound-workqueue specific handling into apply_workqueue_attrs().
Also, factor out unbound pool and pool_workqueue allocation into
alloc_unbound_pwq().

This reorganization is to prepare for NUMA affinity and doesn't
introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
df2d5ae499 workqueue: map an unbound workqueues to multiple per-node pool_workqueues
Currently, an unbound workqueue has only one "current" pool_workqueue
associated with it.  It may have multple pool_workqueues but only the
first pool_workqueue servies new work items.  For NUMA affinity, we
want to change this so that there are multiple current pool_workqueues
serving different NUMA nodes.

Introduce workqueue->numa_pwq_tbl[] which is indexed by NUMA node and
points to the pool_workqueue to use for each possible node.  This
replaces first_pwq() in __queue_work() and workqueue_congested().

numa_pwq_tbl[] is currently initialized to point to the same
pool_workqueue as first_pwq() so this patch doesn't make any behavior
changes.

v2: Use rcu_dereference_raw() in unbound_pwq_by_node() as the function
    may be called only with wq->mutex held.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
2728fd2f09 workqueue: move hot fields of workqueue_struct to the end
Move wq->flags and ->cpu_pwqs to the end of workqueue_struct and align
them to the cacheline.  These two fields are used in the work item
issue path and thus hot.  The scheduled NUMA affinity support will add
dispatch table at the end of workqueue_struct and relocating these two
fields will allow us hitting only single cacheline on hot paths.

Note that wq->pwqs isn't moved although it currently is being used in
the work item issue path for unbound workqueues.  The dispatch table
mentioned above will replace its use in the issue path, so it will
become cold once NUMA support is implemented.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:35 -07:00
Tejun Heo
ecf6881ff3 workqueue: make workqueue->name[] fixed len
Currently workqueue->name[] is of flexible length.  We want to use the
flexible field for something more useful and there isn't much benefit
in allowing arbitrary name length anyway.  Make it fixed len capping
at 24 bytes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:34 -07:00
Tejun Heo
6029a91829 workqueue: add workqueue->unbound_attrs
Currently, when exposing attrs of an unbound workqueue via sysfs, the
workqueue_attrs of first_pwq() is used as that should equal the
current state of the workqueue.

The planned NUMA affinity support will make unbound workqueues make
use of multiple pool_workqueues for different NUMA nodes and the above
assumption will no longer hold.  Introduce workqueue->unbound_attrs
which records the current attrs in effect and use it for sysfs instead
of first_pwq()->attrs.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:34 -07:00
Tejun Heo
f3f90ad469 workqueue: determine NUMA node of workers accourding to the allowed cpumask
When worker tasks are created using kthread_create_on_node(),
currently only per-cpu ones have the matching NUMA node specified.
All unbound workers are always created with NUMA_NO_NODE.

Now that an unbound worker pool may have an arbitrary cpumask
associated with it, this isn't optimal.  Add pool->node which is
determined by the pool's cpumask.  If the pool's cpumask is contained
inside a NUMA node proper, the pool is associated with that node, and
all workers of the pool are created on that node.

This currently only makes difference for unbound worker pools with
cpumask contained inside single NUMA node, but this will serve as
foundation for making all unbound pools NUMA-affine.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:34 -07:00
Tejun Heo
e3c916a4c7 workqueue: drop 'H' from kworker names of unbound worker pools
Currently, all workqueue workers which have negative nice value has
'H' postfixed to their names.  This is necessary for per-cpu workers
as they use the CPU number instead of pool->id to identify the pool
and the 'H' postfix is the only thing distinguishing normal and
highpri workers.

As workers for unbound pools use pool->id, the 'H' postfix is purely
informational.  TASK_COMM_LEN is 16 and after the static part and
delimiters, there are only five characters left for the pool and
worker IDs.  We're expecting to have more unbound pools with the
scheduled NUMA awareness support.  Let's drop the non-essential 'H'
postfix from unbound kworker name.

While at it, restructure kthread_create*() invocation to help future
NUMA related changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:32 -07:00
Tejun Heo
bce903809a workqueue: add wq_numa_tbl_len and wq_numa_possible_cpumask[]
Unbound workqueues are going to be NUMA-affine.  Add wq_numa_tbl_len
and wq_numa_possible_cpumask[] in preparation.  The former is the
highest NUMA node ID + 1 and the latter is masks of possibles CPUs for
each NUMA node.

This patch only introduces these.  Future patches will make use of
them.

v2: NUMA initialization move into wq_numa_init().  Also, the possible
    cpumask array is not created if there aren't multiple nodes on the
    system.  wq_numa_enabled bool added.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:32 -07:00
Tejun Heo
a892cacc7f workqueue: move pwq_pool_locking outside of get/put_unbound_pool()
The scheduled NUMA affinity support for unbound workqueues would need
to walk workqueues list and pool related operations on each workqueue.

Move wq_pool_mutex locking out of get/put_unbound_pool() to their
callers so that pool operations can be performed while walking the
workqueues list, which is also protected by wq_pool_mutex.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:32 -07:00
Tejun Heo
4862125b02 workqueue: fix memory leak in apply_workqueue_attrs()
apply_workqueue_attrs() wasn't freeing temp attrs variable @new_attrs
in its success path.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-04-01 11:23:31 -07:00
Tejun Heo
13e2e55601 workqueue: fix unbound workqueue attrs hashing / comparison
29c91e9912 ("workqueue: implement attribute-based unbound worker_pool
management") implemented attrs based worker_pool matching.  It tried
to avoid false negative when comparing cpumasks with custom hash
function; unfortunately, the hash and comparison functions fail to
ignore CPUs which are not possible.  It incorrectly assumed that
bitmap_copy() skips leftover bits in the last word of bitmap and
cpumask_equal() ignores impossible CPUs.

This patch updates attrs->cpumask handling such that impossible CPUs
are properly ignored.

* Hash and copy functions no longer do anything special.  They expect
  their callers to clear impossible CPUs.

* alloc_workqueue_attrs() initializes the cpumask to cpu_possible_mask
  instead of setting all bits and explicit cpumask_setall() for
  unbound_std_wq_attrs[] in init_workqueues() is dropped.

* apply_workqueue_attrs() is now responsible for ignoring impossible
  CPUs.  It makes a copy of @attrs and clears impossible CPUs before
  doing anything else.

Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-01 11:23:31 -07:00
Tejun Heo
bc0caf099d workqueue: fix race condition in unbound workqueue free path
8864b4e59 ("workqueue: implement get/put_pwq()") implemented pwq
(pool_workqueue) refcnting which frees workqueue when the last pwq
goes away.  It determined whether it was the last pwq by testing
wq->pwqs is empty.  Unfortunately, the test was done outside wq->mutex
and multiple pwq release could race and try to free wq multiple times
leading to oops.

Test wq->pwqs emptiness while holding wq->mutex.

Signed-off-by: Tejun Heo <tj@kernel.org>
2013-04-01 11:23:31 -07:00
David S. Miller
a210576cf8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	net/mac80211/sta_info.c
	net/wireless/core.h

Two minor conflicts in wireless.  Overlapping additions of extern
declarations in net/wireless/core.h and a bug fix overlapping with
the addition of a boolean parameter to __ieee80211_key_free().

Signed-off-by: David S. Miller <davem@davemloft.net>
2013-04-01 13:36:50 -04:00
Stephane Eranian
2fe85427e3 perf: Add PERF_RECORD_MISC_MMAP_DATA to RECORD_MMAP
Type of mapping was lost and made it hard for a tool
to distinguish code vs. data mmaps. Perf has the ability
to distinguish the two.

Use a bit in the header->misc bitmask to keep track of
the mmap type. If PERF_RECORD_MISC_MMAP_DATA is set then
the mapping is not executable (!VM_EXEC). If not set, then
the mapping is executable.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-16-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-04-01 12:19:02 -03:00
Stephane Eranian
d6be9ad6c9 perf: Add generic memory sampling interface
This patch adds PERF_SAMPLE_DATA_SRC.

PERF_SAMPLE_DATA_SRC collects the data source, i.e., where
did the data associated with the sampled instruction
come from. Information is stored in a perf_mem_data_src
structure. It contains opcode, mem level, tlb, snoop,
lock information, subject to availability in hardware.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-8-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-04-01 12:15:59 -03:00
Andi Kleen
c3feedf2aa perf/core: Add weighted samples
For some events it's useful to weight sample with a hardware
provided number. This expresses how expensive the action the
sample represent was.  This allows the profiler to scale
the samples to be more informative to the programmer.

There is already the period which is used similarly, but it
means something different, so I chose to not overload it.
Instead a new sample type for WEIGHT is added.

Can be used for multiple things. Initially it is used for TSX
abort costs and profiling by memory latencies (so to make
expensive load appear higher up in the histograms). The concept
is quite generic and can be extended to many other kinds of
events or architectures, as long as the hardware provides
suitable auxillary values. In principle it could be also used
for software tracepoints.

This adds the generic glue. A new optional sample format for a
64-bit weight value.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: acme@redhat.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-5-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-04-01 12:15:44 -03:00
Paul Walmsley
dbf520a9d7 Revert "lockdep: check that no locks held at freeze time"
This reverts commit 6aa9707099.

Commit 6aa9707099 ("lockdep: check that no locks held at freeze time")
causes problems with NFS root filesystems.  The failures were noticed on
OMAP2 and 3 boards during kernel init:

  [ BUG: swapper/0/1 still has locks held! ]
  3.9.0-rc3-00344-ga937536 #1 Not tainted
  -------------------------------------
  1 lock held by swapper/0/1:
   #0:  (&type->s_umount_key#13/1){+.+.+.}, at: [<c011e84c>] sget+0x248/0x574

  stack backtrace:
    rpc_wait_bit_killable
    __wait_on_bit
    out_of_line_wait_on_bit
    __rpc_execute
    rpc_run_task
    rpc_call_sync
    nfs_proc_get_root
    nfs_get_root
    nfs_fs_mount_common
    nfs_try_mount
    nfs_fs_mount
    mount_fs
    vfs_kern_mount
    do_mount
    sys_mount
    do_mount_root
    mount_root
    prepare_namespace
    kernel_init_freeable
    kernel_init

Although the rootfs mounts, the system is unstable.  Here's a transcript
from a PM test:

  http://www.pwsan.com/omap/testlogs/test_v3.9-rc3/20130317194234/pm/37xxevm/37xxevm_log.txt

Here's what the test log should look like:

  http://www.pwsan.com/omap/testlogs/test_v3.8/20130218214403/pm/37xxevm/37xxevm_log.txt

Mailing list discussion is here:

  http://lkml.org/lkml/2013/3/4/221

Deal with this for v3.9 by reverting the problem commit, until folks can
figure out the right long-term course of action.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Shawn Guo <shawn.guo@linaro.org>
Cc: <maciej.rutecki@gmail.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ben Chan <benchan@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-31 11:38:33 -07:00
Alexandru Copot
2851da5703 audit: pass int* to nlmsg_next
Commit 9419121330 replaced the macros
NLMSG_NEXT with calls to nlmsg_next which produces this warning:

kernel/audit.c: In function ‘audit_receive_skb’:
kernel/audit.c:928:3: warning: passing argument 2 of ‘nlmsg_next’ makes pointer from integer without a cast
In file included from include/net/rtnetlink.h:5:0,
                 from include/net/neighbour.h:28,
                 from include/net/dst.h:17,
                 from include/net/sock.h:68,
                 from kernel/audit.c:55:
include/net/netlink.h:359:1: note: expected ‘int *’ but argument is of type ‘int’

Fix this by sending the intended pointer.

Signed-off-by: Alexandru Copot <alex.mihai.c@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-28 17:40:08 -04:00
Linus Torvalds
2c3de1c2d7 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull userns fixes from Eric W Biederman:
 "The bulk of the changes are fixing the worst consequences of the user
  namespace design oversight in not considering what happens when one
  namespace starts off as a clone of another namespace, as happens with
  the mount namespace.

  The rest of the changes are just plain bug fixes.

  Many thanks to Andy Lutomirski for pointing out many of these issues."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
  userns: Restrict when proc and sysfs can be mounted
  ipc: Restrict mounting the mqueue filesystem
  vfs: Carefully propogate mounts across user namespaces
  vfs: Add a mount flag to lock read only bind mounts
  userns:  Don't allow creation if the user is chrooted
  yama:  Better permission check for ptraceme
  pid: Handle the exit of a multi-threaded init.
  scm: Require CAP_SYS_ADMIN over the current pidns to spoof pids.
2013-03-28 13:43:46 -07:00
Hong zhi guo
9419121330 audit: replace obsolete NLMSG_* with type safe nlmsg_*
Signed-off-by: Hong Zhiguo <honkiko@gmail.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-28 14:25:49 -04:00
David S. Miller
e2a553dbf1 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Conflicts:
	include/net/ipip.h

The changes made to ipip.h in 'net' were already included
in 'net-next' before that header was moved to another location.

Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-27 13:52:49 -04:00
Eric W. Biederman
87a8ebd637 userns: Restrict when proc and sysfs can be mounted
Only allow unprivileged mounts of proc and sysfs if they are already
mounted when the user namespace is created.

proc and sysfs are interesting because they have content that is
per namespace, and so fresh mounts are needed when new namespaces
are created while at the same time proc and sysfs have content that
is shared between every instance.

Respect the policy of who may see the shared content of proc and sysfs
by only allowing new mounts if there was an existing mount at the time
the user namespace was created.

In practice there are only two interesting cases: proc and sysfs are
mounted at their usual places, proc and sysfs are not mounted at all
(some form of mount namespace jail).

Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-27 07:50:08 -07:00
Eric W. Biederman
3151527ee0 userns: Don't allow creation if the user is chrooted
Guarantee that the policy of which files may be access that is
established by setting the root directory will not be violated
by user namespaces by verifying that the root directory points
to the root of the mount namespace at the time of user namespace
creation.

Changing the root is a privileged operation, and as a matter of policy
it serves to limit unprivileged processes to files below the current
root directory.

For reasons of simplicity and comprehensibility the privilege to
change the root directory is gated solely on the CAP_SYS_CHROOT
capability in the user namespace.  Therefore when creating a user
namespace we must ensure that the policy of which files may be access
can not be violated by changing the root directory.

Anyone who runs a processes in a chroot and would like to use user
namespace can setup the same view of filesystems with a mount
namespace instead.  With this result that this is not a practical
limitation for using user namespaces.

Cc: stable@vger.kernel.org
Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Reported-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-27 07:49:29 -07:00
Michael Bohan
84cc8fd2fe hrtimer: Don't reinitialize a cpu_base lock on CPU_UP
The current code makes the assumption that a cpu_base lock won't be
held if the CPU corresponding to that cpu_base is offline, which isn't
always true.

If a hrtimer is not queued, then it will not be migrated by
migrate_hrtimers() when a CPU is offlined. Therefore, the hrtimer's
cpu_base may still point to a CPU which has subsequently gone offline
if the timer wasn't enqueued at the time the CPU went down.

Normally this wouldn't be a problem, but a cpu_base's lock is blindly
reinitialized each time a CPU is brought up. If a CPU is brought
online during the period that another thread is performing a hrtimer
operation on a stale hrtimer, then the lock will be reinitialized
under its feet, and a SPIN_BUG() like the following will be observed:

<0>[   28.082085] BUG: spinlock already unlocked on CPU#0, swapper/0/0
<0>[   28.087078]  lock: 0xc4780b40, value 0x0 .magic: dead4ead, .owner: <none>/-1, .owner_cpu: -1
<4>[   42.451150] [<c0014398>] (unwind_backtrace+0x0/0x120) from [<c0269220>] (do_raw_spin_unlock+0x44/0xdc)
<4>[   42.460430] [<c0269220>] (do_raw_spin_unlock+0x44/0xdc) from [<c071b5bc>] (_raw_spin_unlock+0x8/0x30)
<4>[   42.469632] [<c071b5bc>] (_raw_spin_unlock+0x8/0x30) from [<c00a9ce0>] (__hrtimer_start_range_ns+0x1e4/0x4f8)
<4>[   42.479521] [<c00a9ce0>] (__hrtimer_start_range_ns+0x1e4/0x4f8) from [<c00aa014>] (hrtimer_start+0x20/0x28)
<4>[   42.489247] [<c00aa014>] (hrtimer_start+0x20/0x28) from [<c00e6190>] (rcu_idle_enter_common+0x1ac/0x320)
<4>[   42.498709] [<c00e6190>] (rcu_idle_enter_common+0x1ac/0x320) from [<c00e6440>] (rcu_idle_enter+0xa0/0xb8)
<4>[   42.508259] [<c00e6440>] (rcu_idle_enter+0xa0/0xb8) from [<c000f268>] (cpu_idle+0x24/0xf0)
<4>[   42.516503] [<c000f268>] (cpu_idle+0x24/0xf0) from [<c06ed3c0>] (rest_init+0x88/0xa0)
<4>[   42.524319] [<c06ed3c0>] (rest_init+0x88/0xa0) from [<c0c00978>] (start_kernel+0x3d0/0x434)

As an example, this particular crash occurred when hrtimer_start() was
executed on CPU #0. The code locked the hrtimer's current cpu_base
corresponding to CPU #1. CPU #0 then tried to switch the hrtimer's
cpu_base to an optimal CPU which was online. In this case, it selected
the cpu_base corresponding to CPU #3.

Before it could proceed, CPU #1 came online and reinitialized the
spinlock corresponding to its cpu_base. Thus now CPU #0 held a lock
which was reinitialized. When CPU #0 finally ended up unlocking the
old cpu_base corresponding to CPU #1 so that it could switch to CPU
#3, we hit this SPIN_BUG() above while in switch_hrtimer_base().

CPU #0                            CPU #1
----                              ----
...                               <offline>
hrtimer_start()
lock_hrtimer_base(base #1)
...                               init_hrtimers_cpu()
switch_hrtimer_base()             ...
...                               raw_spin_lock_init(&cpu_base->lock)
raw_spin_unlock(&cpu_base->lock)  ...
<spin_bug>

Solve this by statically initializing the lock.

Signed-off-by: Michael Bohan <mbohan@codeaurora.org>
Link: http://lkml.kernel.org/r/1363745965-23475-1-git-send-email-mbohan@codeaurora.org
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-03-26 21:34:57 +01:00
Paul E. McKenney
6d87669357 Merge branches 'doc.2013.03.12a', 'fixes.2013.03.13a' and 'idlenocb.2013.03.26b' into HEAD
doc.2013.03.12a: Documentation changes.

fixes.2013.03.13a: Miscellaneous fixes.

idlenocb.2013.03.26b: Remove restrictions on no-CBs CPUs, make
	RCU_FAST_NO_HZ take advantage of numbered callbacks, add
	callback acceleration based on numbered callbacks.
2013-03-26 08:07:38 -07:00
Paul E. McKenney
910ee45db2 rcu: Make rcu_accelerate_cbs() note need for future grace periods
Now that rcu_start_future_gp() has been abstracted from
rcu_nocb_wait_gp(), rcu_accelerate_cbs() can invoke rcu_start_future_gp()
so as to register the need for any future grace periods needed by a
CPU about to enter dyntick-idle mode.  This commit makes this change.
Note that some refactoring of rcu_start_gp() is carried out to avoid
recursion and subsequent self-deadlocks.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:58 -07:00
Paul E. McKenney
0446be4897 rcu: Abstract rcu_start_future_gp() from rcu_nocb_wait_gp()
CPUs going idle will need to record the need for a future grace
period, but won't actually need to block waiting on it.  This commit
therefore splits rcu_start_future_gp(), which does the recording, from
rcu_nocb_wait_gp(), which now invokes rcu_start_future_gp() to do the
recording, after which rcu_nocb_wait_gp() does the waiting.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:57 -07:00
Paul E. McKenney
8b425aa8f1 rcu: Rename n_nocb_gp_requests to need_future_gp
CPUs going idle need to be able to indicate their need for future grace
periods.  A mechanism for doing this already exists for no-callbacks
CPUs, so the idea is to re-use that mechanism.  This commit therefore
moves the ->n_nocb_gp_requests field of the rcu_node structure out from
under the CONFIG_RCU_NOCB_CPU #ifdef and renames it to ->need_future_gp.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:56 -07:00
Paul E. McKenney
b8462084a2 rcu: Push lock release to rcu_start_gp()'s callers
If CPUs are to give prior notice of needed grace periods, it will be
necessary to invoke rcu_start_gp() without dropping the root rcu_node
structure's ->lock.  This commit takes a second step in this direction
by moving the release of this lock to rcu_start_gp()'s callers.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:55 -07:00
Paul E. McKenney
bd9f0686fc rcu: Repurpose no-CBs event tracing to future-GP events
Dyntick-idle CPUs need to be able to pre-announce their need for grace
periods.  This can be done using something similar to the mechanism used
by no-CB CPUs to announce their need for grace periods.  This commit
moves in this direction by renaming the no-CBs grace-period event tracing
to suit the new future-grace-period needs.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:54 -07:00
Paul E. McKenney
b92db6cb7e rcu: Rearrange locking in rcu_start_gp()
If CPUs are to give prior notice of needed grace periods, it will be
necessary to invoke rcu_start_gp() without dropping the root rcu_node
structure's ->lock.  This commit takes a first step in this direction
by moving the release of this lock to the end of rcu_start_gp().

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:52 -07:00
Paul E. McKenney
c0f4dfd4f9 rcu: Make RCU_FAST_NO_HZ take advantage of numbered callbacks
Because RCU callbacks are now associated with the number of the grace
period that they must wait for, CPUs can now take advance callbacks
corresponding to grace periods that ended while a given CPU was in
dyntick-idle mode.  This eliminates the need to try forcing the RCU
state machine while entering idle, thus reducing the CPU intensiveness
of RCU_FAST_NO_HZ, which should increase its energy efficiency.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:51 -07:00
Paul E. McKenney
b11cc5760a rcu: Accelerate RCU callbacks at grace-period end
Now that callback acceleration is idempotent, it is safe to accelerate
callbacks during grace-period cleanup on any CPUs that the kthread happens
to be running on.  This commit therefore propagates the completion
of the grace period to the per-CPU data structures, and also adds an
rcu_advance_cbs() just before the cpu_needs_another_gp() check in order
to reduce false-positive grace periods.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:50 -07:00
Paul E. McKenney
5e44ce35a6 rcu: Export RCU_FAST_NO_HZ parameters to sysfs
RCU_FAST_NO_HZ operation is controlled by four compile-time C-preprocessor
macros, but some use cases benefit greatly from runtime adjustment,
particularly when tuning devices.  This commit therefore creates the
corresponding sysfs entries.

Reported-by: Robin Randhawa <robin.randhawa@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:49 -07:00
Paul E. McKenney
a488985851 rcu: Distinguish "rcuo" kthreads by RCU flavor
Currently, the per-no-CBs-CPU kthreads are named "rcuo" followed by
the CPU number, for example, "rcuo".  This is problematic given that
there are either two or three RCU flavors, each of which gets a per-CPU
kthread with exactly the same name.  This commit therefore introduces
a one-letter abbreviation for each RCU flavor, namely 'b' for RCU-bh,
'p' for RCU-preempt, and 's' for RCU-sched.  This abbreviation is used
to distinguish the "rcuo" kthreads, for example, for CPU 0 we would have
"rcuob/0", "rcuop/0", and "rcuos/0".

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
2013-03-26 08:04:48 -07:00
Paul E. McKenney
09c7b89062 rcu: Add event tracing for no-CBs CPUs' grace periods
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:46 -07:00
Paul E. McKenney
21e7a60874 rcu: Add event tracing for no-CBs CPUs' callback registration
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:45 -07:00
Paul E. McKenney
dae6e64d2b rcu: Introduce proper blocking to no-CBs kthreads GP waits
Currently, the no-CBs kthreads do repeated timed waits for grace periods
to elapse.  This is crude and energy inefficient, so this commit allows
no-CBs kthreads to specify exactly which grace period they are waiting
for and also allows them to block for the entire duration until the
desired grace period completes.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:44 -07:00
Paul E. McKenney
911af505ef rcu: Provide compile-time control for no-CBs CPUs
Currently, the only way to specify no-CBs CPUs is via the rcu_nocbs
kernel command-line parameter.  This is inconvenient in some cases,
particularly for randconfig testing, so this commit adds a new set of
kernel configuration parameters.  CONFIG_RCU_NOCB_CPU_NONE (the default)
retains the old behavior, CONFIG_RCU_NOCB_CPU_ZERO offloads callback
processing from CPU 0 (along with any other CPUs specified by the
rcu_nocbs boot-time parameter), and CONFIG_RCU_NOCB_CPU_ALL offloads
callback processing from all CPUs.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-26 08:04:43 -07:00
Eric W. Biederman
751c644b95 pid: Handle the exit of a multi-threaded init.
When a multi-threaded init exits and the initial thread is not the
last thread to exit the initial thread hangs around as a zombie
until the last thread exits.  In that case zap_pid_ns_processes
needs to wait until there are only 2 hashed pids in the pid
namespace not one.

v2. Replace thread_pid_vnr(me) == 1 with the test thread_group_leader(me)
    as suggested by Oleg.

Cc: stable@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Reported-by: Caj Larsson <caj@omnicloud.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
2013-03-26 03:41:23 -07:00
Linus Torvalds
a12183c627 Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
 "A single bugfix which prevents that a non functional timer device is
  selected to provide the fallback device, which is supposed to serve
  timer interrupts on behalf of non functional devices ..."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  clockevents: Don't allow dummy broadcast timers
2013-03-25 18:03:34 -07:00
Nicolas Schichan
d13274794a seccomp: allow BPF_XOR based ALU instructions.
Allow BPF_XOR based ALU instructions.

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Drewry <wad@chromium.org>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2013-03-26 11:07:19 +11:00
Lai Jiangshan
b592760547 workqueue: remove pwq_lock which is no longer used
To simplify locking, the previous patches expanded wq->mutex to
protect all fields of each workqueue instance including the pwqs list
leaving pwq_lock without any user.  Remove the unused pwq_lock.

tj: Rebased on top of the current dev branch.  Updated description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-25 16:57:19 -07:00
Lai Jiangshan
a357fc0326 workqueue: protect wq->saved_max_active with wq->mutex
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.

This patch makes wq->saved_max_active protected by wq->mutex instead
of pwq_lock.  As pwq_lock locking around pwq_adjust_mac_active() is no
longer necessary, this patch also replaces pwq_lock lockings of
for_each_pwq() around pwq_adjust_max_active() to wq->mutex.

tj: Rebased on top of the current dev branch.  Updated description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-25 16:57:19 -07:00
Lai Jiangshan
b09f4fd39c workqueue: protect wq->pwqs and iteration with wq->mutex
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.

init_and_link_pwq() and pwq_unbound_release_workfn() already grab
wq->mutex when adding or removing a pwq from wq->pwqs list.  This
patch makes it official that the list is wq->mutex protected for
writes and updates readers accoridingly.  Explicit IRQ toggles for
sched-RCU read-locking in flush_workqueue_prep_pwqs() and
drain_workqueues() are removed as the surrounding wq->mutex can
provide sufficient synchronization.

Also, assert_rcu_or_pwq_lock() is renamed to assert_rcu_or_wq_mutex()
and checks for wq->mutex too.

pwq_lock locking and assertion are not removed by this patch and a
couple of for_each_pwq() iterations are still protected by it.
They'll be removed by future patches.

tj: Rebased on top of the current dev branch.  Updated description.
    Folded in assert_rcu_or_wq_mutex() renaming from a later patch
    along with associated comment updates.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-25 16:57:18 -07:00
Lai Jiangshan
87fc741e94 workqueue: protect wq->nr_drainers and ->flags with wq->mutex
We're expanding wq->mutex to cover all fields specific to each
workqueue with the end goal of replacing pwq_lock which will make
locking simpler and easier to understand.

wq->nr_drainers and ->flags are specific to each workqueue.  Protect
->nr_drainers and ->flags with wq->mutex instead of pool_mutex.

tj: Rebased on top of the current dev branch.  Updated description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-25 16:57:18 -07:00
Lai Jiangshan
3c25a55daa workqueue: rename wq->flush_mutex to wq->mutex
Currently pwq->flush_mutex protects many fields of a workqueue
including, especially, the pwqs list.  We're going to expand this
mutex to protect most of a workqueue and eventually replace pwq_lock,
which will make locking simpler and easier to understand.

Drop the "flush_" prefix in preparation.

This patch is pure rename.

tj: Rebased on top of the current dev branch.  Updated description.
    Use WQ: and WR: instead of Q: and QR: for synchronization labels.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-25 16:57:17 -07:00
Lai Jiangshan
68e13a67dd workqueue: rename wq_mutex to wq_pool_mutex
wq->flush_mutex will be renamed to wq->mutex and cover all fields
specific to each workqueue and eventually replace pwq_lock, which will
make locking simpler and easier to understand.

Rename wq_mutex to wq_pool_mutex to avoid confusion with wq->mutex.
After the scheduled changes, wq_pool_mutex won't be protecting
anything specific to each workqueue instance anyway.

This patch is pure rename.

tj: s/wqs_mutex/wq_pool_mutex/.  Rewrote description.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-03-25 16:57:17 -07:00
Fengguang Wu
dd5d70e869 timekeeping: __timekeeping_set_tai_offset can be static
Yet again, the kbuild test robot saves the day, noting
I left out defining __timekeeping_set_tai_offset as
static. It even sent me this patch.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-25 12:24:24 -07:00
Rado Vrbovsky
cfea7d7e45 tick: Change log level of NOHZ: local_softirq_pending message
The "NOHZ: local_softirq_pending" message is a largely informational
message.  This makes extra work for customers that have a policy of
investigating all kernel log messages logged at <= KERN_ERR log level.
This patch sets the message to a different log level.

[ tglx: Use pr_warn() ]

Signed-off-by: Rado Vrbovsky <rvrbovsk@redhat.com>
Cc: Don Zickus <dzickus@redhat.com>
Link: http://lkml.kernel.org/r/2037057938.893524.1360345050772.JavaMail.root@redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-03-25 10:46:59 +01:00
David Daney
8ffbc7d9ff hrtimer/trivial: Fix comment text in hrtimer.c
The comments mention HRTIMER_ABS and HRTIMER_REL, these symbols don't
exist, the proper names are HRTIMER_MODE_ABS and HRTIMER_MODE_REL.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Jiri Kosina <trivial@kernel.org>
Link: http://lkml.kernel.org/r/1363202438-21234-1-git-send-email-ddaney.cavm@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-03-25 10:46:59 +01:00
Oleg Nesterov
2ca067efd8 poweroff: change orderly_poweroff() to use schedule_work()
David said:

    Commit 6c0c0d4d10 ("poweroff: fix bug in orderly_poweroff()")
    apparently fixes one bug in orderly_poweroff(), but introduces
    another.  The comments on orderly_poweroff() claim it can be called
    from any context - and indeed we call it from interrupt context in
    arch/powerpc/platforms/pseries/ras.c for example.  But since that
    commit this is no longer safe, since call_usermodehelper_fns() is not
    safe in interrupt context without the UMH_NO_WAIT option.

orderly_poweroff() can be used from any context but UMH_WAIT_EXEC is
sleepable.  Move the "force" logic into __orderly_poweroff() and change
orderly_poweroff() to use the global poweroff_work which simply calls
__orderly_poweroff().

While at it, remove the unneeded "int argc" and change argv_split() to
use GFP_KERNEL.

We use the global "bool poweroff_force" to pass the argument, this can
obviously affect the previous request if it is pending/running.  So we
only allow the "false => true" transition assuming that the pending
"true" should succeed anyway.  If schedule_work() fails after that we
know that work->func() was not called yet, it must see the new value.

This means that orderly_poweroff() becomes async even if we do not run
the command and always succeeds, schedule_work() can only fail if the
work is already pending.  We can export __orderly_poweroff() and change
the non-atomic callers which want the old semantics.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Feng Hong <hongfeng@marvell.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-22 16:41:20 -07:00
Frederic Weisbecker
dc72c32e1f printk: Provide a wake_up_klogd() off-case
wake_up_klogd() is useless when CONFIG_PRINTK=n because neither printk()
nor printk_sched() are in use and there are actually no waiter on
log_wait waitqueue.  It should be a stub in this case for users like
bust_spinlocks().

Otherwise this results in this warning when CONFIG_PRINTK=n and
CONFIG_IRQ_WORK=n:

	kernel/built-in.o In function `wake_up_klogd':
	(.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue'

To fix this, provide an off-case for wake_up_klogd() when
CONFIG_PRINTK=n.

There is much more from console_unlock() and other console related code
in printk.c that should be moved under CONFIG_PRINTK.  But for now,
focus on a minimal fix as we passed the merged window already.

[akpm@linux-foundation.org: include printk.h in bust_spinlocks.c]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: James Hogan <james.hogan@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-22 16:41:20 -07:00
Thomas Gleixner
9a7a71b1d0 timekeeping: Split timekeeper_lock into lock and seqcount
We want to shorten the seqcount write hold time. So split the seqlock
into a lock and a seqcount.

Open code the seqwrite_lock in the places which matter and drop the
sequence counter update where it's pointless.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[jstultz: Merge fixups from CLOCK_TAI collisions]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:20:01 -07:00
Thomas Gleixner
7e40672d93 timekeeping: Move lock out of timekeeper struct
Make the lock a separate entity. Preparatory patch for shadow
timekeeper structure.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[Merged with CLOCK_TAI changes]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:20:00 -07:00
Thomas Gleixner
eb93e4d930 timekeeping: Make jiffies_lock internal
Nothing outside of the timekeeping core needs that lock.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:20:00 -07:00
Thomas Gleixner
23a9537a69 timekeeping: Calc stuff once
Calculate the cycle interval shifted value once. No functional change,
just makes the code more readable.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:19:59 -07:00
John Stultz
90adda98b8 hrtimer: Add hrtimer support for CLOCK_TAI
Add hrtimer support for CLOCK_TAI, as well as posix timer interfaces.

Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:19:59 -07:00
John Stultz
1ff3c9677b timekeeping: Add CLOCK_TAI clockid
This add a CLOCK_TAI clockid and the needed accessors.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:19:59 -07:00
John Stultz
cc244ddae6 timekeeping: Move TAI managment into timekeeping core from ntp
Currently NTP manages the TAI offset. Since there's plans for a
CLOCK_TAI clockid, push the TAI management into the timekeeping
core.

CC: Thomas Gleixner <tglx@linutronix.de>
CC: Eric Dumazet <eric.dumazet@gmail.com>
CC: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-22 16:19:58 -07:00
Linus Torvalds
cd82346934 Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
 "A fair chunk of the linecount comes from a fix for a tracing bug that
  corrupts latency tracing buffers when the overwrite mode is changed on
  the fly - the rest is mostly assorted fewliner fixlets."

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Add SNB/SNB-EP scheduling constraints for cycle_activity event
  kprobes/x86: Check Interrupt Flag modifier when registering probe
  kprobes: Make hash_64() as always inlined
  perf: Generate EXIT event only once per task context
  perf: Reset hwc->last_period on sw clock events
  tracing: Prevent buffer overwrite disabled for latency tracers
  tracing: Keep overwrite in sync between regular and snapshot buffers
  tracing: Protect tracer flags with trace_types_lock
  perf tools: Fix LIBNUMA build with glibc 2.12 and older.
  tracing: Fix free of probe entry by calling call_rcu_sched()
  perf/POWER7: Create a sysfs format entry for Power7 events
  perf probe: Fix segfault
  libtraceevent: Remove hard coded include to /usr/local/include in Makefile
  perf record: Fix -C option
  perf tools: check if -DFORTIFY_SOURCE=2 is allowed
  perf report: Fix build with NO_NEWT=1
  perf annotate: Fix build with NO_NEWT=1
  tracing: Fix race in snapshot swapping
2013-03-21 08:29:11 -07:00
Stephane Eranian
dd9c086d9f perf: Fix ring_buffer perf_output_space() boundary calculation
This patch fixes a flaw in perf_output_space(). In case the size
of the space needed is bigger than the actual buffer size, there
may be situations where the function would return true (i.e.,
there is space) when it should not. head > offset due to
rounding of the masking logic.

The problem can be tested by activating BTS on Intel processors.
A BTS record can be as big as 16 pages. The following command
fails:

  $ perf record -m 4 -c 1 -e branches:u my_test_program

You will get a buffer corruption with this. Perf report won't be
able to parse the perf.data.

The fix is to first check that the requested space is smaller
than the buffer size. If so, then the masking logic will work
fine. If not, then there is no chance the record can be saved
and it will be gracefully handled by upper code layers.

[ In v2, we also make the logic for the writable more explicit by
  renaming it to rb->overwrite because it tells whether or not the
  buffer can overwrite its tail (suggested by PeterZ). ]

Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: peterz@infradead.org
Cc: jolsa@redhat.com
Cc: fweisbec@gmail.com
Link: http://lkml.kernel.org/r/20130318133327.GA3056@quad
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-21 12:04:35 +01:00
Tejun Heo
383efcd000 sched: Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s
try_to_wake_up_local() should only be invoked to wake up another
task in the same runqueue and BUG_ON()s are used to enforce the
rule. Missing try_to_wake_up_local() can stall workqueue
execution but such stalls are likely to be finite either by
another work item being queued or the one blocked getting
unblocked.  There's no reason to trigger BUG while holding rq
lock crashing the whole system.

Convert BUG_ON()s in try_to_wake_up_local() to WARN_ON_ONCE()s.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20130318192234.GD3042@htj.dyndns.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-21 11:48:20 +01:00
Ingo Molnar
3bf2391729 Merge branch 'perf/urgent' into perf/core
Merge in all pending fixes, before pulling the latest development
bits from Arnaldo - which will involve merge conflicts.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-21 11:03:10 +01:00
Steven Rostedt (Red Hat)
22f45649ce tracing: Update debugfs README file
Update the README file in debugfs/tracing to something more useful.
What's currently in the file is very old and what it shows doesn't
have much use. Heck, it tells you how to mount debugfs! But to read
this file you would have already needed to mount it.

Replace the file with current up-to-date information. It's rather
limited, but what do you expect from a pseudo README file.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-20 21:55:02 -04:00
Lai Jiangshan
519e3c1163 workqueue: avoid false negative in assert_manager_or_pool_lock()
If lockdep complains something for other subsystem, lockdep_is_held()
can be false negative, so we need to also test debug_locks before
triggering WARN.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 11:21:34 -07:00
Lai Jiangshan
881094532e workqueue: use rcu_read_lock_sched() instead for accessing pwq in RCU
rcu_read_lock_sched() is better than preempt_disable() if the code is
protected by RCU_SCHED.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 11:00:57 -07:00
Lai Jiangshan
951a078a52 workqueue: kick a worker in pwq_adjust_max_active()
If pwq_adjust_max_active() changes max_active from 0 to
saved_max_active, it needs to wakeup worker.  This is already done by
thaw_workqueues().

If pwq_adjust_max_active() increases max_active for an unbound wq,
while not strictly necessary for correctness, it's still desirable to
wake up a worker so that the requested concurrency level is reached
sooner.

Move wake_up_worker() call from thaw_workqueues() to
pwq_adjust_max_active() so that it can handle both of the above two
cases.  This also makes thaw_workqueues() simpler.

tj: Updated comments and description.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 10:52:30 -07:00
Lai Jiangshan
6a092dfd51 workqueue: simplify current_is_workqueue_rescuer()
We can test worker->recue_wq instead of reaching into
current_pwq->wq->rescuer and then comparing it to self.

tj: Commit message.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 10:40:25 -07:00
Jesper Derehag
2b5faa4c55 connector: Added coredumping event to the process connector
Process connector can now also detect coredumping events.

Main aim of patch is get notified at start of coredumping, instead of
having to wait for it to finish and then being notified through EXIT
event.

Could be used for instance by process-managers that want to get
notified as soon as possible about process failures, and not
necessarily beeing notified after coredump, which could be in the
order of minutes depending on size of coredump, piping and so on.

Signed-off-by: Jesper Derehag <jderehag@hotmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2013-03-20 13:23:21 -04:00
Lai Jiangshan
12ee4fc67c workqueue: add missing POOL_FREEZING
get_unbound_pool() forgot to set POOL_FREEZING if workqueue_freezing
is set and a new pool could go out of sync with the global freezing
state.

Fix it by adding POOL_FREEZING if workqueue_freezing.  wq_mutex is
already held so no further locking is necessary.  This also removes
the unused static variable warning when !CONFIG_FREEZER.

tj: Updated commit message.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 10:19:09 -07:00
Li Zefan
081aa458c3 cgroup: consolidate cgroup_attach_task() and cgroup_attach_proc()
These two functions share most of the code.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 07:50:25 -07:00
Li Zefan
3ac1707a13 cgroup: fix an off-by-one bug which may trigger BUG_ON()
The 3rd parameter of flex_array_prealloc() is the number of elements,
not the index of the last element.

The effect of the bug is, when opening cgroup.procs, a flex array will
be allocated and all elements of the array is allocated with
GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to
allocate memory for it, it'll trigger a BUG_ON().

Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
2013-03-20 07:50:04 -07:00
Tejun Heo
7dbc725e47 workqueue: restore CPU affinity of unbound workers on CPU_ONLINE
With the recent addition of the custom attributes support, unbound
pools may have allowed cpumask which isn't full.  As long as some of
CPUs in the cpumask are online, its workers will maintain cpus_allowed
as set on worker creation; however, once no online CPU is left in
cpus_allowed, the scheduler will reset cpus_allowed of any workers
which get scheduled so that they can execute.

To remain compliant to the user-specified configuration, CPU affinity
needs to be restored when a CPU becomes online for an unbound pool
which doesn't currently have any online CPUs before.

This patch implement restore_unbound_workers_cpumask(), which is
called from CPU_ONLINE for all unbound pools, checks whether the
coming up CPU is the first allowed online one, and, if so, invokes
set_cpus_allowed_ptr() with the configured cpumask on all workers.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-03-19 13:45:21 -07:00
Tejun Heo
a9ab775bca workqueue: directly restore CPU affinity of workers from CPU_ONLINE
Rebinding workers of a per-cpu pool after a CPU comes online involves
a lot of back-and-forth mostly because only the task itself could
adjust CPU affinity if PF_THREAD_BOUND was set.

As CPU_ONLINE itself couldn't adjust affinity, it had to somehow
coerce the workers themselves to perform set_cpus_allowed_ptr().  Due
to the various states a worker can be in, this led to three different
paths a worker may be rebound.  worker->rebind_work is queued to busy
workers.  Idle ones are signaled by unlinking worker->entry and call
idle_worker_rebind().  The manager isn't covered by either and
implements its own mechanism.

PF_THREAD_BOUND has been relaced with PF_NO_SETAFFINITY and CPU_ONLINE
itself now can manipulate CPU affinity of workers.  This patch
replaces the existing rebind mechanism with direct one where
CPU_ONLINE iterates over all workers using for_each_pool_worker(),
restores CPU affinity, and clears WORKER_UNBOUND.

There are a couple subtleties.  All bound idle workers should have
their runqueues set to that of the bound CPU; however, if the target
task isn't running, set_cpus_allowed_ptr() just updates the
cpus_allowed mask deferring the actual migration to when the task
wakes up.  This is worked around by waking up idle workers after
restoring CPU affinity before any workers can become bound.

Another subtlety is stems from matching @pool->nr_running with the
number of running unbound workers.  While DISASSOCIATED, all workers
are unbound and nr_running is zero.  As workers become bound again,
nr_running needs to be adjusted accordingly; however, there is no good
way to tell whether a given worker is running without poking into
scheduler internals.  Instead of clearing UNBOUND directly,
rebind_workers() replaces UNBOUND with another new NOT_RUNNING flag -
REBOUND, which will later be cleared by the workers themselves while
preparing for the next round of work item execution.  The only change
needed for the workers is clearing REBOUND along with PREP.

* This patch leaves for_each_busy_worker() without any user.  Removed.

* idle_worker_rebind(), busy_worker_rebind_fn(), worker->rebind_work
  and rebind logic in manager_workers() removed.

* worker_thread() now looks at WORKER_DIE instead of testing whether
  @worker->entry is empty to determine whether it needs to do
  something special as dying is the only special thing now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-03-19 13:45:21 -07:00
Tejun Heo
bd7c089eb2 workqueue: relocate rebind_workers()
rebind_workers() will be reimplemented in a way which makes it mostly
decoupled from the rest of worker management.  Move rebind_workers()
so that it's located with other CPU hotplug related functions.

This patch is pure function relocation.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-03-19 13:45:21 -07:00
Tejun Heo
822d8405d1 workqueue: convert worker_pool->worker_ida to idr and implement for_each_pool_worker()
Make worker_ida an idr - worker_idr and use it to implement
for_each_pool_worker() which will be used to simplify worker rebinding
on CPU_ONLINE.

pool->worker_idr is protected by both pool->manager_mutex and
pool->lock so that it can be iterated while holding either lock.

* create_worker() allocates ID without installing worker pointer and
  installs the pointer later using idr_replace().  This is because
  worker ID is needed when creating the actual task to name it and the
  new worker shouldn't be visible to iterations before fully
  initialized.

* In destroy_worker(), ID removal is moved before kthread_stop().
  This is again to guarantee that only fully working workers are
  visible to for_each_pool_worker().

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
2013-03-19 13:45:21 -07:00
Tejun Heo
14a40ffccd sched: replace PF_THREAD_BOUND with PF_NO_SETAFFINITY
PF_THREAD_BOUND was originally used to mark kernel threads which were
bound to a specific CPU using kthread_bind() and a task with the flag
set allows cpus_allowed modifications only to itself.  Workqueue is
currently abusing it to prevent userland from meddling with
cpus_allowed of workqueue workers.

What we need is a flag to prevent userland from messing with
cpus_allowed of certain kernel tasks.  In kernel, anyone can
(incorrectly) squash the flag, and, for worker-type usages,
restricting cpus_allowed modification to the task itself doesn't
provide meaningful extra proection as other tasks can inject work
items to the task anyway.

This patch replaces PF_THREAD_BOUND with PF_NO_SETAFFINITY.
sched_setaffinity() checks the flag and return -EINVAL if set.
set_cpus_allowed_ptr() is no longer affected by the flag.

This will allow simplifying workqueue worker CPU affinity management.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-03-19 13:45:20 -07:00
Daniel Vetter
0d4a42f6bd Linux 3.9-rc3
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Merge tag 'v3.9-rc3' into drm-intel-next-queued

Backmerge so that I can merge Imre Deak's coalesced sg entries fixes,
which depend upon the new for_each_sg_page introduce in

commit a321e91b6d
Author: Imre Deak <imre.deak@intel.com>
Date:   Wed Feb 27 17:02:56 2013 -0800

    lib/scatterlist: add simple page iterator

The merge itself is just two trivial conflicts:

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2013-03-19 09:47:30 +01:00
Linus Torvalds
b63dc123b2 Merge branch 'for-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
 "Lai's patch to fix highly unlikely but still possible workqueue stall
  during CPU hotunplug."

* 'for-3.9-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: fix possible pool stall bug in wq_unbind_fn()
2013-03-18 18:47:07 -07:00
Namhyung Kim
86e213e1d9 perf/cgroup: Add __percpu annotation to perf_cgroup->info
It's a per-cpu data structure but missed the __percpu annotation.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Link: http://lkml.kernel.org/r/1363600594-11453-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 11:02:06 +01:00
Peter Zijlstra
a8d7ad52a7 sched/tracing: Allow tracing the preemption decision on wakeup
Thomas noted that we do the wakeup preemption check after the
wakeup trace point, this means the tracepoint cannot test/report
this decision; which is rather important for latency sensitive
workloads. Therefore move the tracepoint after doing the
preemption check.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1363254519.26965.9.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 10:18:08 +01:00
Ingo Molnar
e75c8b475e Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core
Pull CPU runtime stats/accounting fixes from Frederic Weisbecker:

 " Some users are complaining that their threadgroup's runtime accounting
   freezes after a week or so of intense cpu-bound workload. This set tries
   to fix the issue by reducing the risk of multiplication overflow in the
   cputime scaling code. "

Stanislaw Gruszka further explained the historic context and impact of the
bug:

 " Commit 0cf55e1ec0 start to use scalling
   for whole thread group, so increase chances of hitting multiplication
   overflow, depending on how many CPUs are on the system.

   We have multiplication utime * rtime for one thread since commit
   b27f03d4bd.

   Overflow will happen after:

   rtime * utime > 0xffffffffffffffff jiffies

   if thread utilize 100% of CPU time, that gives:

   rtime > sqrt(0xffffffffffffffff) jiffies

   ritme > sqrt(0xffffffffffffffff) / (24 * 60 * 60 * HZ) days

   For HZ 100 it will be 497 days for HZ 1000 it will be 49 days.

   Bug affect only users, who run CPU intensive application for that
   long period. Also they have to be interested on utime,stime values,
   as bug has no other visible effect as making those values incorrect. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 10:09:31 +01:00
Ingo Molnar
1f1b396758 Merge branch 'tip/perf/urgent-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace into perf/urgent
Pull tracing fixes from Steven Rostedt.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 09:48:29 +01:00
Namhyung Kim
d610d98b5d perf: Generate EXIT event only once per task context
perf_event_task_event() iterates pmu list and generate events
for each eligible pmu context.  But if task_event has task_ctx
like in EXIT it'll generate events even though the pmu doesn't
have an eligible one. Fix it by moving the code to proper
places.

Before this patch:

  $ perf record -n true
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.006 MB perf.data (~248 samples) ]

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4
  cycles stats:
             TOTAL events:         73
              MMAP events:         67
              COMM events:          2
              EXIT events:          4

After this patch:

  $ perf report -D | tail
  Aggregated stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1
  cycles stats:
             TOTAL events:         70
              MMAP events:         67
              COMM events:          2
              EXIT events:          1

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363332433-7637-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 09:47:33 +01:00
Namhyung Kim
778141e3cf perf: Reset hwc->last_period on sw clock events
When cpu/task clock events are initialized, their sampling
frequencies are converted to have a fixed value.  However it
missed to update the hwc->last_period which was set to 1 for
initial sampling frequency calibration.

Because this hwc->last_period value is used as a period in
perf_swevent_ hrtime(), every recorded sample will have an
incorrected period of 1.

  $ perf record -e task-clock noploop 1
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.158 MB perf.data (~6919 samples) ]

  $ perf report -n --show-total-period  --stdio
  # Samples: 4K of event 'task-clock'
  # Event count (approx.): 4000
  #
  # Overhead       Samples        Period  Command  Shared Object              Symbol
  # ........  ............  ............  .......  .............  ..................
  #
      99.95%          3998          3998  noploop  noploop        [.] main
       0.03%             1             1  noploop  libc-2.15.so   [.] init_cacheinfo
       0.03%             1             1  noploop  ld-2.15.so     [.] open_verify

Note that it doesn't affect the non-sampling event so that the
perf stat still gets correct value with or without this patch.

  $ perf stat -e task-clock noploop 1

   Performance counter stats for 'noploop 1':

         1000.272525 task-clock                #    1.000 CPUs utilized

         1.000560605 seconds time elapsed

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1363574507-18808-1-git-send-email-namhyung@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 09:15:18 +01:00
Feng Tang
e445cf1c42 timekeeping: utilize the suspend-nonstop clocksource to count suspended time
There are some new processors whose TSC clocksource won't stop during
suspend. Currently, after system resumes, kernel will use persistent
clock or RTC to compensate the sleep time, but with these nonstop
clocksources, we could skip the special compensation from external
sources, and just use current clocksource for time recounting.

This can solve some time drift bugs caused by some not-so-accurate or
error-prone RTC devices.

The current way to count suspended time is first try to use the persistent
clock, and then try the RTC if persistent clock can't be used. This
patch will change the trying order to:
	suspend-nonstop clocksource -> persistent clock -> RTC

When counting the sleep time with nonstop clocksource, use an accurate way
suggested by Jason Gunthorpe to cover very large delta cycles.

Signed-off-by: Feng Tang <feng.tang@intel.com>
[jstultz: Small optimization, avoiding re-reading the clocksource]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-15 16:51:29 -07:00
John Stultz
7859e404ae timekeeping: Use inject_offset in warp_clock
When warping the clock (from a local time RTC), use
timekeeping_inject_offset() to atomically add the offset.

This avoids any minor time error caused by the delay between
reading the time, and then setting the adjusted time.

Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-15 16:50:20 -07:00
Dong Zhu
c30bd09915 timekeeping: Avoid adjust kernel time once hwclock kept in UTC time
If the Hardware Clock kept in local time,kernel will adjust the time
to be UTC time.But if Hardware Clock kept in UTC time,system will make
a dummy settimeofday call first (sys_tz.tz_minuteswest = 0) to make sure
the time is not shifted,so at this point I think maybe it is not necessary
to set the kernel time once the sys_tz.tz_minuteswest is zero.

Signed-off-by: Dong Zhu <bluezhudong@gmail.com>
[jstultz: Updated to merge with conflicting changes ]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-03-15 16:50:12 -07:00
Steven Rostedt (Red Hat)
7fe70b579c tracing: Fix ftrace_dump()
ftrace_dump() had a lot of issues. What ftrace_dump() does, is when
ftrace_dump_on_oops is set (via a kernel parameter or sysctl), it
will dump out the ftrace buffers to the console when either a oops,
panic, or a sysrq-z occurs.

This was written a long time ago when ftrace was fragile to recursion.
But it wasn't written well even for that.

There's a possible deadlock that can occur if a ftrace_dump() is happening
and an NMI triggers another dump. This is because it grabs a lock
before checking if the dump ran.

It also totally disables ftrace, and tracing for no good reasons.

As the ring_buffer now checks if it is read via a oops or NMI, where
there's a chance that the buffer gets corrupted, it will disable
itself. No need to have ftrace_dump() do the same.

ftrace_dump() is now cleaned up where it uses an atomic counter to
make sure only one dump happens at a time. A simple atomic_inc_return()
is enough that is needed for both other CPUs and NMIs. No need for
a spinlock, as if one CPU is running the dump, no other CPU needs
to do it too.

The tracing_on variable is turned off and not turned on. The original
code did this, but it wasn't pretty. By just disabling this variable
we get the result of not seeing traces that happen between crashes.

For sysrq-z, it doesn't get turned on, but the user can always write
a '1' to the tracing_on file. If they are using sysrq-z, then they should
know about tracing_on.

The new code is much easier to read and less error prone. No more
deadlock possibility when an NMI triggers here.

Reported-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: stable@vger.kernel.org
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 19:24:56 -04:00
zhangwei(Jovi)
52f6ad6dc3 tracing: Rename trace_event_mutex to trace_event_sem
trace_event_mutex is an rw semaphore now, not a mutex, change the name.

Link: http://lkml.kernel.org/r/513D843B.40109@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
[ Forward ported to my new code ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 13:22:10 -04:00
zhangwei(Jovi)
36a78e9e87 tracing: Fix comment about prefix in arch_syscall_match_sym_name()
ppc64 has its own syscall prefix like ".SyS" or ".sys". Make the
comment in arch_syscall_match_sym_name() more understandable.

Link: http://lkml.kernel.org/r/513D842F.40205@huawei.com

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-15 13:22:09 -04:00