This patch provides performance tuning for the "Bulldozer" CPU. With its
shared instruction cache there is a chance of generating an excessive
number of cache cross-invalidates when running specific workloads on the
cores of a compute module.
This excessive amount of cross-invalidations can be observed if cache
lines backed by shared physical memory alias in bits [14:12] of their
virtual addresses, as those bits are used for the index generation.
This patch addresses the issue by clearing all the bits in the [14:12]
slice of the file mapping's virtual address at generation time, thus
forcing those bits the same for all mappings of a single shared library
across processes and, in doing so, avoids instruction cache aliases.
It also adds the command line option "align_va_addr=(32|64|on|off)" with
which virtual address alignment can be enabled for 32-bit or 64-bit x86
individually, or both, or be completely disabled.
This change leaves virtual region address allocation on other families
and/or vendors unaffected.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/1312550110-24160-2-git-send-email-bp@amd64.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Multiple attempts to dynamically reallocate pci resources have
unfortunately lead to regressions. Though we continue to fix the
regressions and fine tune the dynamic-reallocation behavior, we have not
reached a acceptable state yet.
This patch provides a interim solution. It disables dynamic reallocation
by default, but adds the ability to enable it through pci=realloc kernel
command line parameter.
Tested-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Some USB mass-storage devices have bugs that cause them not to handle
the first READ(10) command they receive correctly. The Corsair
Padlock v2 returns completely bogus data for its first read (possibly
it returns the data in encrypted form even though the device is
supposed to be unlocked). The Feiya SD/SDHC card reader fails to
complete the first READ(10) command after it is plugged in or after a
new card is inserted, returning a status code that indicates it thinks
the command was invalid, which prevents the kernel from retrying the
read.
Since the first read of a new device or a new medium is for the
partition sector, the kernel is unable to retrieve the device's
partition table. Users have to manually issue an "hdparm -z" or
"blockdev --rereadpt" command before they can access the device.
This patch (as1470) works around the problem. It adds a new quirk
flag, US_FL_INVALID_READ10, indicating that the first READ(10) should
always be retried immediately, as should any failing READ(10) commands
(provided the preceding READ(10) command succeeded, to avoid getting
stuck in a loop). The patch also adds appropriate unusual_devs
entries containing the new flag.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Sven Geggus <sven-usbst@geggus.net>
Tested-by: Paul Hartman <paul.hartman+linux@gmail.com>
CC: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
CC: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* git://git.infradead.org/iommu-2.6:
intel-iommu: Fix off-by-one in RMRR setup
intel-iommu: Add domain check in domain_remove_one_dev_info
intel-iommu: Remove Host Bridge devices from identity mapping
intel-iommu: Use coherent DMA mask when requested
intel-iommu: Dont cache iova above 32bit
intel-iommu: Speed up processing of the identity_mapping function
intel-iommu: Check for identity mapping candidate using system dma mask
intel-iommu: Only unlink device domains from iommu
intel-iommu: Enable super page (2MiB, 1GiB, etc.) support
intel-iommu: Flush unmaps at domain_exit
intel-iommu: Remove obsolete comment from detect_intel_iommu
intel-iommu: fix VT-d PMR disable for TXT on S3 resume
There are no externally-visible changes with this. In the loop in the
internal __domain_mapping() function, we simply detect if we are mapping:
- size >= 2MiB, and
- virtual address aligned to 2MiB, and
- physical address aligned to 2MiB, and
- on hardware that supports superpages.
(and likewise for larger superpages).
We automatically use a superpage for such mappings. We never have to
worry about *breaking* superpages, since we trust that we will always
*unmap* the same range that was mapped. So all we need to do is ensure
that dma_pte_clear_range() will also cope with superpages.
Adjust pfn_to_dma_pte() to take a superpage 'level' as an argument, so
it can return a PTE at the appropriate level rather than always
extending the page tables all the way down to level 1. Again, this is
simplified by the fact that we should never encounter existing small
pages when we're creating a mapping; any old mapping that used the same
virtual range will have been entirely removed and its obsolete page
tables freed.
Provide an 'intel_iommu=sp_off' argument on the command line as a
chicken bit. Not that it should ever be required.
==
The original commit seen in the iommu-2.6.git was Youquan's
implementation (and completion) of my own half-baked code which I'd
typed into an email. Followed by half a dozen subsequent 'fixes'.
I've taken the unusual step of rewriting history and collapsing the
original commits in order to keep the main history simpler, and make
life easier for the people who are going to have to backport this to
older kernels. And also so I can give it a more coherent commit comment
which (hopefully) gives a better explanation of what's going on.
The original sequence of commits leading to identical code was:
Youquan Song (3):
intel-iommu: super page support
intel-iommu: Fix superpage alignment calculation error
intel-iommu: Fix superpage level calculation error in dma_pfn_level_pte()
David Woodhouse (4):
intel-iommu: Precalculate superpage support for dmar_domain
intel-iommu: Fix hardware_largepage_caps()
intel-iommu: Fix inappropriate use of superpages in __domain_mapping()
intel-iommu: Fix phys_pfn in __domain_mapping for sglist pages
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
The noswapaccount parameter has been deprecated since 2.6.38 without any
complaints from users so we can remove it. swapaccount=0|1 can be used
instead.
As we are removing the parameter we can also clean up swapaccount because
it doesn't have to accept an empty string anymore (to match noswapaccount)
and so we can push = into __setup macro rather than checking "=1" resp.
"=0" strings
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'usb-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (205 commits)
USB: EHCI: Remove SPARC_LEON {read,write}_be definitions from ehci.h
USB: UHCI: Support big endian GRUSBHC HC
sparc: add {read,write}*_be routines
USB: UHCI: Add support for big endian descriptors
USB: UHCI: Use ACCESS_ONCE rather than using a full compiler barrier
USB: UHCI: Add support for big endian mmio
usb-storage: Correct adjust_quirks to include latest flags
usb/isp1760: Fix possible unlink problems
usb/isp1760: Move function isp1760_endpoint_disable() within file.
USB: remove remaining usages of hcd->state from usbcore and fix regression
usb: musb: ux500: add configuration and build options for ux500 dma
usb: musb: ux500: add dma glue layer for ux500
usb: musb: ux500: add dma name for ux500
usb: musb: ux500: add ux500 specific code for gadget side
usb: musb: fix compile error
usb-storage: fix up the unusual_realtek device list
USB: gadget: f_audio: Fix invalid dereference of initdata
EHCI: don't rescan interrupt QHs needlessly
OHCI: fix regression caused by nVidia shutdown workaround
USB: OTG: msm: Free VCCCX regulator even if we can't set the voltage
...
Commits ae38c78a03
and 00914025cc added quirk flags
US_FL_NO_READ_DISC_INFO and US_FL_NO_READ_CAPACITY_16 to
the usb-storage driver. However they did not add the corresponding flags
to adjust_quirks() in usb.c, so there was no facility for a user
to over-ride/add them via the quirks module parameter.
Signed-off-by: Karl Relton <karllinuxtest.relton@ntlworld.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Enable/disable newly documented SMEP (Supervisor Mode Execution Protection) CPU
feature in kernel. CR4.SMEP (bit 20) is 0 at power-on. If the feature is
supported by CPU (X86_FEATURE_SMEP), enable SMEP by setting CR4.SMEP. New kernel
option nosmep disables the feature even if the feature is supported by CPU.
[ hpa: moved the call to setup_smep() until after the vendor-specific
initialization; that ensures that CPUID features are unmasked. We
will still run it before we have userspace (never mind uncontrolled
userspace). ]
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
LKML-Reference: <1305157865-31727-1-git-send-email-fenghua.yu@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
acpi_sleep=s4_nonvs is superseded by acpi_sleep=nonvs, so remove it.
Signed-off-by: WANG Cong <amwang@redhat.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Len Brown <lenb@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Fix some minor typos:
* informations => information
* there own => their own
* these => this
Signed-off-by: Sylvestre Ledru <sylvestre.ledru@scilab.org>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a little more info for some of the panic-related kernel parameters.
Fix "oops=panic" to fit in 80 columns.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Reviewed-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On some architectures, the boot process involves de-registering the boot
console (early boot), initialize drivers and then re-register the console.
This mechanism introduces a window in which no printk can happen on the
console and messages are buffered and then printed once the new console is
available.
If a kernel crashes during this window, all it's left on the boot console
is "console [foo] enabled, bootconsole disabled" making debug of the crash
rather 'interesting'.
By adding "keep_bootcon" option, do not unregister the boot console, that
will allow to printk everything that is happening up to the crash.
The option is clearly meant only for debugging purposes as it introduces
lots of duplicated info printed on console, but will make bug report from
users easier as it doesn't require a kernel build just to figure out where
we crash.
Signed-off-by: Fabio M. Di Nitto <fabbione@fabbione.net>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a cpu is considered stuck, instead of limping along and just printing
a warning, it is sometimes preferred to just panic, let kdump capture the
vmcore and reboot. This gets the machine back into a stable state quickly
while saving the info that got it into a stuck state to begin with.
Add a Kconfig option to allow users to set the hardlockup to panic
by default. Also add in a 'nmi_watchdog=nopanic' to override this.
[akpm@linux-foundation.org: fix strncmp length]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The oops=panic cmdline option is not x86 specific, move it to generic code.
Update documentation.
Signed-off-by: Olaf Hering <olaf@aepfle.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'nfs-for-2.6.39' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6: (54 commits)
RPC: killing RPC tasks races fixed
xprt: remove redundant check
SUNRPC: Convert struct rpc_xprt to use atomic_t counters
SUNRPC: Ensure we always run the tk_callback before tk_action
sunrpc: fix printk format warning
xprt: remove redundant null check
nfs: BKL is no longer needed, so remove the include
NFS: Fix a warning in fs/nfs/idmap.c
Cleanup: Factor out some cut-and-paste code.
cleanup: save 60 lines/100 bytes by combining two mostly duplicate functions.
NFS: account direct-io into task io accounting
gss:krb5 only include enctype numbers in gm_upcall_enctypes
RPCRDMA: Fix FRMR registration/invalidate handling.
RPCRDMA: Fix to XDR page base interpretation in marshalling logic.
NFSv4: Send unmapped uid/gids to the server when using auth_sys
NFSv4: Propagate the error NFS4ERR_BADOWNER to nfs4_do_setattr
NFSv4: cleanup idmapper functions to take an nfs_server argument
NFSv4: Send unmapped uid/gids to the server if the idmapper fails
NFSv4: If the server sends us a numeric uid/gid then accept it
NFSv4.1: reject zero layout with zeroed stripe unit
...
The new behaviour is enabled using the new module parameter
'nfs4_disable_idmapping'.
Note that if the server rejects an unmapped uid or gid, then
the client will automatically switch back to using the idmapper.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
If firmware allows us to map all of a partition's memory for DMA on a
particular bridge, create a 1:1 mapping of that memory. Add hooks for
dealing with hotplug events. Dynamic DMA windows can use larger than the
default page size, and we use the largest one possible.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Add a commandline parameter "threadirqs" which forces all interrupts except
those marked IRQF_NO_THREAD to run threaded. That's mostly a debug option to
allow retrieving better debug data from crashing interrupt handlers. If
"threadirqs" is not enabled on the kernel command line, then there is no
impact in the interrupt hotpath.
Architecture code needs to select CONFIG_IRQ_FORCED_THREADING after
marking the interrupts which cant be threaded IRQF_NO_THREAD. All
interrupts which have IRQF_TIMER set are implict marked
IRQF_NO_THREAD. Also all PER_CPU interrupts are excluded.
Forced threading hard interrupts also forces all soft interrupt
handling into thread context.
When enabled it might slow down things a bit, but for debugging problems in
interrupt code it's a reasonable penalty as it does not immediately
crash and burn the machine when an interrupt handler is buggy.
Some test results on a Core2Duo machine:
Cache cold run of:
# time git grep irq_desc
non-threaded threaded
real 1m18.741s 1m19.061s
user 0m1.874s 0m1.757s
sys 0m5.843s 0m5.427s
# iperf -c server
non-threaded
[ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 933 Mbits/sec
threaded
[ 3] 0.0-10.0 sec 1.09 GBytes 939 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 934 Mbits/sec
[ 3] 0.0-10.0 sec 1.09 GBytes 937 Mbits/sec
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20110223234956.772668648@linutronix.de>
Update the "log_buf_len" description to use [KMG] syntax for the
buffer size.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The '[KMG]' suffix is commonly described after a number of kernel
parameter values documentation. Explicitly state its semantics.
Signed-off-by: Ahmed S. Darwish <darwish.07@gmail.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6: (59 commits)
ACPI / PM: Fix build problems for !CONFIG_ACPI related to NVS rework
ACPI: fix resource check message
ACPI / Battery: Update information on info notification and resume
ACPI: Drop device flag wake_capable
ACPI: Always check if _PRW is present before trying to evaluate it
ACPI / PM: Check status of power resources under mutexes
ACPI / PM: Rename acpi_power_off_device()
ACPI / PM: Drop acpi_power_nocheck
ACPI / PM: Drop acpi_bus_get_power()
Platform / x86: Make fujitsu_laptop use acpi_bus_update_power()
ACPI / Fan: Rework the handling of power resources
ACPI / PM: Register power resource devices as soon as they are needed
ACPI / PM: Register acpi_power_driver early
ACPI / PM: Add function for updating device power state consistently
ACPI / PM: Add function for device power state initialization
ACPI / PM: Introduce __acpi_bus_get_power()
ACPI / PM: Introduce function for refcounting device power resources
ACPI / PM: Add functions for manipulating lists of power resources
ACPI / PM: Prevent acpi_power_get_inferred_state() from making changes
ACPICA: Update version to 20101209
...
* 'kvm-updates/2.6.38' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (142 commits)
KVM: Initialize fpu state in preemptible context
KVM: VMX: when entering real mode align segment base to 16 bytes
KVM: MMU: handle 'map_writable' in set_spte() function
KVM: MMU: audit: allow audit more guests at the same time
KVM: Fetch guest cr3 from hardware on demand
KVM: Replace reads of vcpu->arch.cr3 by an accessor
KVM: MMU: only write protect mappings at pagetable level
KVM: VMX: Correct asm constraint in vmcs_load()/vmcs_clear()
KVM: MMU: Initialize base_role for tdp mmus
KVM: VMX: Optimize atomic EFER load
KVM: VMX: Add definitions for more vm entry/exit control bits
KVM: SVM: copy instruction bytes from VMCB
KVM: SVM: implement enhanced INVLPG intercept
KVM: SVM: enhance mov DR intercept handler
KVM: SVM: enhance MOV CR intercept handler
KVM: SVM: add new SVM feature bit names
KVM: cleanup emulate_instruction
KVM: move complete_insn_gp() into x86.c
KVM: x86: fix CR8 handling
KVM guest: Fix kvm clock initialization when it's configured out
...
Enable async PF in a guest if async PF capability is discovered.
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (72 commits)
powerpc/pseries: Fix build of topology stuff without CONFIG_NUMA
powerpc/pseries: Fix VPHN build errors on non-SMP systems
powerpc/83xx: add mpc8308_p1m DMA controller device-tree node
powerpc/83xx: add DMA controller to mpc8308 device-tree node
powerpc/512x: try to free dma descriptors in case of allocation failure
powerpc/512x: add MPC8308 dma support
powerpc/512x: fix the hanged dma transfer issue
powerpc/512x: scatter/gather dma fix
powerpc/powermac: Make auto-loading of therm_pm72 possible
of/address: Use propper endianess in get_flags
powerpc/pci: Use printf extension %pR for struct resource
powerpc: Remove unnecessary casts of void ptr
powerpc: Disable VPHN polling during a suspend operation
powerpc/pseries: Poll VPA for topology changes and update NUMA maps
powerpc: iommu: Add device name to iommu error printks
powerpc: Record vma->phys_addr in ioremap()
powerpc: Update compat_arch_ptrace
powerpc: Fix PPC_PTRACE_SETHWDEBUG on PPC_BOOK3S
powerpc/time: printk time stamp init not correct
powerpc: Minor cleanups for machdep.h
...
i8042 controller present in Dell Vostro V13 errorneously signals spurious
timeouts.
Introduce i8042.notimeout parameter for ignoring i8042-signalled timeouts
and apply this quirk automatically for Dell Vostro V13, based on DMI match.
In addition to that, this machine also needs to be added to nomux blacklist.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
* 'x86-tsc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: Check tsc available/disabled in the delayed init function
x86: Improve TSC calibration using a delayed workqueue
x86: Make tsc=reliable override boot time stability checks
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits)
sched: Change wait_for_completion_*_timeout() to return a signed long
sched, autogroup: Fix reference leak
sched, autogroup: Fix potential access to freed memory
sched: Remove redundant CONFIG_CGROUP_SCHED ifdef
sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight
sched: Move periodic share updates to entity_tick()
printk: Use this_cpu_{read|write} api on printk_pending
sched: Make pushable_tasks CONFIG_SMP dependant
sched: Add 'autogroup' scheduling feature: automated per session task groups
sched: Fix unregister_fair_sched_group()
sched: Remove unused argument dest_cpu to migrate_task()
mutexes, sched: Introduce arch_mutex_cpu_relax()
sched: Add some clock info to sched_debug
cpu: Remove incorrect BUG_ON
cpu: Remove unused variable
sched: Fix UP build breakage
sched: Make task dump print all 15 chars of proc comm
sched: Update tg->shares after cpu.shares write
sched: Allow update_cfs_load() to update global load
sched: Implement demand based update_cfs_load()
...
re:
commit e9d376f0fa
Author: Jason Baron <jbaron@redhat.com>
Date: Thu Feb 5 11:51:38 2009 -0500
dynamic debug: combine dprintk and dynamic printk
Above commit obsoleted the kernel parameter, and even removed its
entry in kernel-parameters.txt, but got reinsterted through
0cb55ad2ad ("docs: alphabetize entries in kernel-parameters.txt")
Signed-off-by: Jim Cromie <jim.cromie@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The error message 'NMI watchdog failed to create perf event...'
does not make it clear that this is a fatal error for the
watchdog. It also currently prints the error value as a
pointer, rather than extracting the error code with PTR_ERR().
Fix that.
Add a note to the description of the 'nowatchdog' kernel
parameter to associate it with this message.
Reported-by: Cesare Leonardi <celeonar@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Cc: 599368@bugs.debian.org
Cc: 608138@bugs.debian.org
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org> # .37.x and later
LKML-Reference: <1294009362.3167.126.camel@localhost>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the ACPI video output switching control as it never works.
With the patch applied,
ACPI video driver still catches the video output notification,
but it does nothing but raises the notification to userspace.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Originally adapted from Huang Ying's patch which moved the
unknown_nmi_panic to the traps.c file. Because the old nmi
watchdog was deleted before this change happened, the
unknown_nmi_panic sysctl was lost. This re-adds it.
Also, the nmi_watchdog sysctl was re-implemented and its
documentation updated accordingly.
Patch-inspired-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com>
Acked-by: Yinghai Lu <yinghai@kernel.org>
Cc: fweisbec@gmail.com
LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
A recurring complaint from CFS users is that parallel kbuild has
a negative impact on desktop interactivity. This patch
implements an idea from Linus, to automatically create task
groups. Currently, only per session autogroups are implemented,
but the patch leaves the way open for enhancement.
Implementation: each task's signal struct contains an inherited
pointer to a refcounted autogroup struct containing a task group
pointer, the default for all tasks pointing to the
init_task_group. When a task calls setsid(), a new task group
is created, the process is moved into the new task group, and a
reference to the preveious task group is dropped. Child
processes inherit this task group thereafter, and increase it's
refcount. When the last thread of a process exits, the
process's reference is dropped, such that when the last process
referencing an autogroup exits, the autogroup is destroyed.
At runqueue selection time, IFF a task has no cgroup assignment,
its current autogroup is used.
Autogroup bandwidth is controllable via setting it's nice level
through the proc filesystem:
cat /proc/<pid>/autogroup
Displays the task's group and the group's nice level.
echo <nice level> > /proc/<pid>/autogroup
Sets the task group's shares to the weight of nice <level> task.
Setting nice level is rate limited for !admin users due to the
abuse risk of task group locking.
The feature is enabled from boot by default if
CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via
the boot option noautogroup, and can also be turned on/off on
the fly via:
echo [01] > /proc/sys/kernel/sched_autogroup_enabled
... which will automatically move tasks to/from the root task group.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Paul Turner <pjt@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
[ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
