Commit Graph

176724 Commits

Author SHA1 Message Date
Jack Steiner
9178052fda gru: handle blades without memory
Do not use alloc_pages_exact_node() to allocate GRU tables.  If a blade
has no local memory, nid will be -1.  Use alloc_pages_node() instead.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Jack Steiner
b61fc69bb6 gru: fix istatus race in GRU tlb dropin
TLB dropins require updates to the CBR instruction istatus field.  This is
needed to resolve race conditions in the chip.

The code currently uses the user address of the CBR.  This works but opens
up additional endcases related to stealing of contexts and accessing the
CBR from tasks that do not have access to the user address space.  (Some
of this non-user task access is debug code that is not currently being
pushed to the community).

User CBRs are also directly accessible using the kernel mapping of the
CBR.  Change the TLB dropin code to use the the kernel mapping of the CBR.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Jack Steiner
091f1a1061 gru: add comments raised in previous code reviews
Add comments from previous code reviews.  The comments help explain some
of the more esoteric aspects of the driver.

Move a free() to the other side of an unlock.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Jack Steiner
827f02febf gru: initial GRU based on blade topology
Change the GRU initialization code to initialize based on blade topology
instead of node topology.  The result is the same but blade-based
initialization is cleaner.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
57e6d258b1 UV - XPC: pass nasid instead of nid to gru_create_message_queue
Currently, the UV xpc code is passing nid to the gru_create_message_queue
instead of nasid as it expects.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
046d6c563b x86: uv: XPC receive message reuse triggers invalid BUG_ON()
This was a difficult bug to trip.  XPC was in the middle of sending an
acknowledgement for a received message.

In xpc_received_payload_uv():
.
        ret = xpc_send_gru_msg(ch->sn.uv.cached_notify_gru_mq_desc, msg,
                               sizeof(struct xpc_notify_mq_msghdr_uv));
        if (ret != xpSuccess)
                XPC_DEACTIVATE_PARTITION(&xpc_partitions[ch->partid], ret);

        msg->hdr.msg_slot_number += ch->remote_nentries;

at the point in xpc_send_gru_msg() where the hardware has dispatched the
acknowledgement, the remote side is able to reuse the message structure
and send a message with a different slot number.  This problem is made
worse by interrupts.

The adjustment of msg_slot_number and the BUG_ON in
xpc_handle_notify_mq_msg_uv() which verifies the msg_slot_number is
consistent are only used for debug purposes.  Since a fix for this that
preserves the debug functionality would either have to infringe upon the
payload or allocate another structure just for debug, I decided to remove
it entirely.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
dbd2918ec6 X86: uv: xpc_make_first_contact hang due to not accepting ACTIVE state
Many times while the initial connection is being made, the contacted
partition will send back both the ACTIVATING and the ACTIVE
remote_act_state changes in very close succescion.  The 1/4 second delay
in the make first contact loop is large enough to nearly always miss the
ACTIVATING state change.

Since either state indicates the remote partition has acknowledged our
state change, accept either.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
15b87d67ff x86: uv: xpc NULL deref when mesq becomes empty
Under heavy load conditions, our set of xpc messages may become exhausted.
 The code handles this correctly with the exception of the management code
which hits a NULL pointer dereference.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
c2c9f11574 x86: uv: update XPC to handle updated BIOS interface
The UV BIOS has moved the location of some of their pointers to the
"partition reserved page" from memory into a uv hub MMR.  The GRU does not
support bcopy operations from MMR space so we need to special case the MMR
addresses using VLOAD operations.

Additionally, the BIOS call for registering a message queue watchlist has
removed the 'blade' value and eliminated the structure that was being
passed in.  This is also reflected in this patch.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:14 -08:00
Robin Holt
289750d1f1 X86: uv: implement a gru_read_gpa kernel function
The BIOS has decided to store a pointer to the partition reserved page in
a scratch MMR.  The GRU is only able to read an MMR using a vload
instruction.  The gru_read_gpa() function will implemented.

Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Robin Holt
fae419f2ab x86: uv: introduce uv_gpa_is_mmr
Provide a mechanism for determining if a global physical address is
pointing to a UV hub MMR.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Robin Holt
682128939f x86: uv: xpc needs to provide an abstraction for uv_gpa
Provide an SGI SN2/UV agnositic method for converting a global physical
address into a socket physical address.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Robin Holt
729d69e699 x86: uv: introduce a means to translate from gpa -> socket_paddr
The UV BIOS has been updated to implement some of our interface
functionality differently than originally expected.  These patches update
the kernel to the bios implementation and include a few minor bug fixes
which prevent us from doing significant testing on real hardware.

This patch:

For SGI UV systems, translate from a global physical address back to a
socket physical address.  This does nothing to ensure the socket physical
address is actually addressable by the kernel.  That is the responsibility
of the user of the function.

Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Christoph Hellwig
5fe878ae7f direct-io: cleanup blockdev_direct_IO locking
Currently the locking in blockdev_direct_IO is a mess, we have three
different locking types and very confusing checks for some of them.  The
most complicated one is DIO_OWN_LOCKING for reads, which happens to not
actually be used.

This patch gets rid of the DIO_OWN_LOCKING - as mentioned above the read
case is unused anyway, and the write side is almost identical to
DIO_NO_LOCKING.  The difference is that DIO_NO_LOCKING always sets the
create argument for the get_blocks callback to zero, but we can easily
move that to the actual get_blocks callbacks.  There are four users of the
DIO_NO_LOCKING mode: gfs already ignores the create argument and thus is
fine with the new version, ocfs2 only errors out if create were ever set,
and we can remove this dead code now, the block device code only ever uses
create for an error message if we are fully beyond the device which can
never happen, and last but not least XFS will need the new behavour for
writes.

Now we can replace the lock_type variable with a flags one, where no flag
means the DIO_NO_LOCKING behaviour and DIO_LOCKING is kept as the first
flag.  Separate out the check for not allowing to fill holes into a
separate flag, although for now both flags always get set at the same
time.

Also revamp the documentation of the locking scheme to actually make
sense.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Zach Brown <zach.brown@oracle.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alex Elder <aelder@sgi.com>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Jeff Moyer
23aee091d8 dio: don't zero out the pages array inside struct dio
Intel reported a performance regression caused by the following commit:

commit 848c4dd515
Author: Zach Brown <zach.brown@oracle.com>
Date:   Mon Aug 20 17:12:01 2007 -0700

    dio: zero struct dio with kzalloc instead of manually

    This patch uses kzalloc to zero all of struct dio rather than
    manually trying to track which fields we rely on being zero.  It
    passed aio+dio stress testing and some bug regression testing on
    ext3.

    This patch was introduced by Linus in the conversation that lead up
    to Badari's minimal fix to manually zero .map_bh.b_state in commit:

      6a648fa721

    It makes the code a bit smaller.  Maybe a couple fewer cachelines to
    load, if we're lucky:

       text    data     bss     dec     hex filename
    3285925  568506 1304616 5159047  4eb887 vmlinux
    3285797  568506 1304616 5158919  4eb807 vmlinux.patched

    I was unable to measure a stable difference in the number of cpu
    cycles spent in blockdev_direct_IO() when pushing aio+dio 256K reads
    at ~340MB/s.

    So the resulting intent of the patch isn't a performance gain but to
    avoid exposing ourselves to the risk of finding another field like
    .map_bh.b_state where we rely on zeroing but don't enforce it in the
    code.

Zach surmised that zeroing out the page array was what caused most of
the problem, and suggested the approach taken in the attached patch for
resolving the issue.  Intel re-tested with this patch and saw a 0.6%
performance gain (the original regression was 0.5%).

[akpm@linux-foundation.org: add comment]
Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Acked-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Shaohua Li
fac046ad0b aio: remove unused field
Don't know the reason, but it appears ki_wait field of iocb never gets used.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
David Howells
ea58ceb543 FS-Cache: Avoid maybe-used-uninitialised warning on variable
Andrew Morton's compiler sees the following warning in FS-Cache:

fs/fscache/object-list.c: In function 'fscache_objlist_lookup':
fs/fscache/object-list.c:94: warning: 'obj' may be used uninitialized in this function

which my compiler doesn't.  This is a false positive as obj can only be
used in the comparison against minobj if minobj has been set to something
other than NULL, but for that to happen, obj has to be first set to
something.

Deal with this by preclearing obj too.

Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Amerigo Wang
06a7f71124 kexec: premit reduction of the reserved memory size
Implement shrinking the reserved memory for crash kernel, if it is more
than enough.

For example, if you have already reserved 128M, now you just want 100M,
you can do:

# echo $((100*1024*1024)) > /sys/kernel/kexec_crash_size

Note, you can only do this before loading the crash kernel.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Acked-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:13 -08:00
Joe Perches
1f2c19f8c9 parport_pc.c: use correct length in strncmp
Signed-off-by: Joe Perches <joe@perches.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Jan Beulich
ac2b3e67dd dma-mapping: fix off-by-one error in dma_capable()
dma_mask is, when interpreted as address, the last valid byte, and hence
comparison msut also be done using the last valid of the buffer in
question.

Also fix the open-coded instances in lib/swiotlb.c.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Becky Bruce <beckyb@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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>
2009-12-16 07:20:12 -08:00
Nils Carlson
bbead2104e edac: i5100 add 6 ranks per channel
Add support for 6 ranks per channel to the i5100 chipset.  I have tested
the patch as far as possible with correctible errors and things appear
good.  The DIMM mapping is correct for our board, but boards may differ.

Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se>
Acked-by: Arthur Jones <ajones@riverbed.com>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Nils Carlson
295439f2a3 edac: i5100 add scrubbing
Addscrubbing to the i5100 chipset.  The i5100 chipset only supports one
scrubbing rate, which is not constant but dependent on memory load.  The
rate returned by this driver is an estimate based on some experimentation,
but is substantially closer to the truth than the speed supplied in the
documentation.

Also, scrubbing is done once, and then a done-bit is set.  This means that
to accomplish continuous scrubbing a re-enabling mechanism must be used.
I have created the simplest possible such mechanism in the form of a
work-queue which will check every five minutes.  This interval is quite
arbitrary but should be sufficient for all sizes of system memory.

Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Nils Carlson
b18dfd05f9 edac: i5100 clean controller to channel terms
The i5100 driver uses the word controller instead of channel in a lot of
places, this is simply a cleanup of the patch.

Signed-off-by: Nils Carlson <nils.carlson@ludd.ltu.se>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
André Goddard Rosa
417e315247 pid: reduce code size by using a pointer to iterate over array
It decreases code size by 16 bytes on my gcc 4.4.1 on Core 2:
  text    data     bss     dec     hex filename
  4314    2216       8    6538    198a kernel/pid.o-BEFORE
  4298    2216       8    6522    197a kernel/pid.o-AFTER

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
André Goddard Rosa
7be6d991bc pid: tighten pidmap spinlock critical section by removing kfree()
Avoid calling kfree() under pidmap spinlock, calling it afterwards.

Normally kfree() is fast, but sometimes it can be slow, so avoid
calling it under the spinlock if we can do it.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Christoph Hellwig
698ba7b5a3 elf: kill USE_ELF_CORE_DUMP
Currently all architectures but microblaze unconditionally define
USE_ELF_CORE_DUMP.  The microblaze omission seems like an error to me, so
let's kill this ifdef and make sure we are the same everywhere.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <linux-arch@vger.kernel.org>
Cc: Michal Simek <michal.simek@petalogix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:12 -08:00
Julia Lawall
d1da96aada drivers/char/ipmi: Use KCS_IDLE_STATE
KCS_IDLE and KCS_IDLE state have the same value, but in this function the
constants ending in _STATE are compared to the state variable.

Signed-off-by: Julia Lawall <julia@diku.dk>
Acked-by: Core Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Amerigo Wang
9cf18e1dd7 ipc: HARD_MSGMAX should be higher not lower on 64bit
We have HARD_MSGMAX lower on 64bit than on 32bit, since usually 64bit
machines have more memory than 32bit machines.

Making it higher on 64bit seems reasonable, and keep the original number
on 32bit.

Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Amerigo Wang
e5cc9c7b1a ipc: remove unreachable code in sem.c
This line is unreachable, remove it.

[akpm@linux-foundation.org: remove unneeded initialisation of `err']
Signed-off-by: WANG Cong <amwang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Manfred Spraul
d987f8b213 ipc/sem.c: optimize single sops when semval is zero
If multiple simple decrements on the same semaphore are pending, then the
current code scans all decrement operations, even if the semaphore value
is already 0.

The patch optimizes that: if the semaphore value is 0, then there is no
need to scan the q->alter entries.

Note that this is a common case: It happens if 100 decrements by one are
pending and now an increment by one increases the semaphore value from 0
to 1.  Without this patch, all 100 entries are scanned.  With the patch,
only one entry is scanned, then woken up.  Then the new rule triggers and
the scanning is aborted, without looking at the remaining 99 tasks.

With this patch, single sop increment/decrement by 1 are now O(1).
(same as with Nick's patch)

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Manfred Spraul
636c6be823 ipc/sem.c: optimize single semop operations
sysv sem has the concept of semaphore arrays that consist out of multiple
semaphores.  Atomic operations that affect multiple semaphores are
supported.

The patch optimizes single semaphore operation calls that affect only one
semaphore: It's not necessary to scan all pending operations, it is
sufficient to scan the per-semaphore list.

The idea is from Nick Piggin version of an ipc sem improvement, the
implementation is different: The code tries to keep as much common code as
possible.

As the result, the patch is simpler, but optimizes fewer cases.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Manfred Spraul
b97e820fff ipc/sem.c: add a per-semaphore pending list
Based on Nick's findings:

sysv sem has the concept of semaphore arrays that consist out of multiple
semaphores.  Atomic operations that affect multiple semaphores are
supported.

The patch is the first step for optimizing simple, single semaphore
operations: In addition to the global list of all pending operations, a
2nd, per-semaphore list with the simple operations is added.

Note: this patch does not make sense by itself, the new list is used
nowhere.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:10 -08:00
Manfred Spraul
b6e90822e7 ipc/sem.c: optimize if semops fail
Reduce the amount of scanning of the list of pending semaphore operations:
If try_atomic_semop failed, then no changes were applied.  Thus no need to
restart.

Additionally, this patch correct an incorrect comment: It's possible to
wait for arbitrary semaphore values (do a dec by <x>, wait-for-zero, inc
by <x> in one atomic operation)

Both changes are from Nick Piggin, the patch is the result of a different
split of the individual changes.

Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Nick Piggin
d4212093dc ipc/sem.c: sem preempt improve
The strange sysv semaphore wakeup scheme has a kind of busy-wait lock
involved, which could deadlock if preemption is enabled during the "lock".

It is an implementation detail (due to a spinlock being held) that this is
actually the case.  However if "spinlocks" are made preemptible, or if the
sem lock is changed to a sleeping lock for example, then the wakeup would
become buggy.  So this might be a bugfix for -rt kernels.

Imagine waker being preempted by wakee and never clearing IN_WAKEUP -- if
wakee has higher RT priority then there is a priority inversion deadlock.
Even if there is not a priority inversion to cause a deadlock, then there
is still time wasted spinning.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Nick Piggin
9cad200c76 ipc/sem.c: sem use list operations
Replace the handcoded list operations in update_queue() with the standard
list_for_each_entry macros.

list_for_each_entry_safe() must be used, because list entries can
disappear immediately uppon the wakeup event.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Nick Piggin
bf17bb7177 ipc/sem.c: sem optimise undo list search
Around a month ago, there was some discussion about an improvement of the
sysv sem algorithm: Most (at least: some important) users only use simple
semaphore operations, therefore it's worthwile to optimize this use case.

This patch:

Move last looked up sem_undo struct to the head of the task's undo list.
Attempt to move common entries to the front of the list so search time is
reduced.  This reduces lookup_undo on oprofile of problematic SAP workload
by 30% (see patch 4 for a description of SAP workload).

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Pierre Peiffer <peifferp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Serge E. Hallyn
7d6feeb287 ipc ns: fix memory leak (idr)
We have apparently had a memory leak since
7ca7e564e0 "ipc: store ipcs into IDRs" in
2007.  The idr of which 3 exist for each ipc namespace is never freed.

This patch simply frees them when the ipcns is freed.  I don't believe any
idr_remove() are done from rcu (and could therefore be delayed until after
this idr_destroy()), so the patch should be safe.  Some quick testing
showed no harm, and the memory leak fixed.

Caught by kmemleak.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Oleg Nesterov
1be53963b0 signals: check ->group_stop_count after tracehook_get_signal()
Move the call to do_signal_stop() down, after tracehook call.  This makes
->group_stop_count condition visible to tracers before do_signal_stop()
will participate in this group-stop.

Currently the patch has no effect, tracehook_get_signal() always returns 0.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Oleg Nesterov
ad09750b51 signals: kill force_sig_specific()
Kill force_sig_specific(), this trivial wrapper has no callers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Oleg Nesterov
7486e5d9fc signals: cosmetic, collect_signal: use SI_USER
Trivial, s/0/SI_USER/ in collect_signal() for grep.

This is a bit confusing, we don't know the source of this signal.
But we don't care, and "info->si_code = 0" is imho worse.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Oleg Nesterov
dd34200adc signals: send_signal: use si_fromuser() to detect from_ancestor_ns
Change send_signal() to use si_fromuser().  From now SEND_SIG_NOINFO
triggers the "from_ancestor_ns" check.

This fixes reparent_thread()->group_send_sig_info(pdeath_signal)
behaviour, before this patch send_signal() does not detect the
cross-namespace case when the child of the dying parent belongs to the
sub-namespace.

This patch can affect the behaviour of send_sig(), kill_pgrp() and
kill_pid() when the caller sends the signal to the sub-namespace with
"priv == 0" but surprisingly all callers seem to use them correctly,
including disassociate_ctty(on_exit).

Except: drivers/staging/comedi/drivers/addi-data/*.c incorrectly use
send_sig(priv => 0).  But his is minor and should be fixed anyway.

Reported-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:09 -08:00
Oleg Nesterov
614c517d7c signals: SEND_SIG_NOINFO should be considered as SI_FROMUSER()
No changes in compiled code. The patch adds the new helper, si_fromuser()
and changes check_kill_permission() to use this helper.

The real effect of this patch is that from now we "officially" consider
SEND_SIG_NOINFO signal as "from user-space" signals. This is already true
if we look at the code which uses SEND_SIG_NOINFO, except __send_signal()
has another opinion - see the next patch.

The naming of these special SEND_SIG_XXX siginfo's is really bad
imho.  From __send_signal()'s pov they mean

	SEND_SIG_NOINFO		from user
	SEND_SIG_PRIV		from kernel
	SEND_SIG_FORCED		no info

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Reviewed-by: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
d519650373 ptrace: x86: change syscall_trace_leave() to rely on tracehook when stepping
Suggested by Roland.

Unlike powepc, x86 always calls tracehook_report_syscall_exit(step) with
step = 0, and sends the trap by hand.

This results in unnecessary SIGTRAP when PTRACE_SINGLESTEP follows the
syscall-exit stop.

Change syscall_trace_leave() to pass the correct "step" argument to
tracehook and remove the send_sigtrap() logic.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
7f38551fc3 ptrace: x86: implement user_single_step_siginfo()
Suggested by Roland.

Implement user_single_step_siginfo() for x86.  Extract this code from
send_sigtrap().

Since x86 calls tracehook_report_syscall_exit(step => 0) the new helper is
not used yet.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
2f0edac555 ptrace: change tracehook_report_syscall_exit() to handle stepping
Suggested by Roland.

Change tracehook_report_syscall_exit() to look at step flag and send the
trap signal if needed.

This change affects ia64, microblaze, parisc, powerpc, sh.  They pass
nonzero "step" argument to tracehook but since it was ignored the tracee
reports via ptrace_notify(), this is not right and not consistent.

	- PTRACE_SETSIGINFO doesn't work

	- if the tracer resumes the tracee with signr != 0 the new signal
	  is generated rather than delivering it

	- If PT_TRACESYSGOOD is set the tracee reports the wrong exit_code

I don't have a powerpc machine, but I think this test-case should see the
difference:

	#include <unistd.h>
	#include <sys/ptrace.h>
	#include <sys/wait.h>
	#include <assert.h>
	#include <stdio.h>

	int main(void)
	{
		int pid, status;

		if (!(pid = fork())) {
			assert(ptrace(PTRACE_TRACEME) == 0);
			kill(getpid(), SIGSTOP);

			getppid();

			return 0;
		}

		assert(pid == wait(&status));
		assert(ptrace(PTRACE_SETOPTIONS, pid, 0, PTRACE_O_TRACESYSGOOD) == 0);

		assert(ptrace(PTRACE_SYSCALL, pid, 0,0) == 0);
		assert(pid == wait(&status));

		assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0);
		assert(pid == wait(&status));

		if (status == 0x57F)
			return 0;

		printf("kernel bug: status=%X shouldn't have 0x80\n", status);
		return 1;
	}

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
25baa35bef ptrace: powerpc: implement user_single_step_siginfo()
Suggested by Roland.

Implement user_single_step_siginfo() for powerpc.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
85ec7fd9f8 ptrace: introduce user_single_step_siginfo() helper
Suggested by Roland.

Currently there is no way to synthesize a single-stepping trap in the
arch-independent manner.  This patch adds the default helper which fills
siginfo_t, arch/ can can override it.

Architetures which implement user_enable_single_step() should add
user_single_step_siginfo() also.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: <linux-arch@vger.kernel.org>
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>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
6580807da1 ptrace: copy_process() should disable stepping
If the tracee calls fork() after PTRACE_SINGLESTEP, the forked child
starts with TIF_SINGLESTEP/X86_EFLAGS_TF bits copied from ptraced parent.
This is not right, especially when the new child is not auto-attaced: in
this case it is killed by SIGTRAP.

Change copy_process() to call user_disable_single_step(). Tested on x86.

Test-case:

	#include <stdio.h>
	#include <unistd.h>
	#include <signal.h>
	#include <sys/ptrace.h>
	#include <sys/wait.h>
	#include <assert.h>

	int main(void)
	{
		int pid, status;

		if (!(pid = fork())) {
			assert(ptrace(PTRACE_TRACEME) == 0);
			kill(getpid(), SIGSTOP);

			if (!fork()) {
				/* kernel bug: this child will be killed by SIGTRAP */
				printf("Hello world\n");
				return 43;
			}

			wait(&status);
			return WEXITSTATUS(status);
		}

		for (;;) {
			assert(pid == wait(&status));
			if (WIFEXITED(status))
				break;
			assert(ptrace(PTRACE_SINGLESTEP, pid, 0,0) == 0);
		}

		assert(WEXITSTATUS(status) == 43);
		return 0;
	}

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:08 -08:00
Oleg Nesterov
c6a47cc2cc ptrace: cleanup ptrace_init_task()->ptrace_link() path
No functional changes.

ptrace_init_task() looks confusing, as if we always auto-attach when "bool
ptrace" argument is true, while in fact we attach only if current is
traced.

Make the code more explicit and kill now unused ptrace_link().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-12-16 07:20:08 -08:00
Bob Liu
aa20d489ce memcg: code clean, remove unused variable in mem_cgroup_resize_limit()
Variable `progress' isn't used in mem_cgroup_resize_limit() any more.
Remove it.

[akpm@linux-foundation.org: cleanup]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: 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>
2009-12-16 07:20:08 -08:00