slub: only IPI CPUs that have per cpu obj to flush

flush_all() is called for each kmem_cache_destroy().  So every cache being
destroyed dynamically ends up sending an IPI to each CPU in the system,
regardless if the cache has ever been used there.

For example, if you close the Infinband ipath driver char device file, the
close file ops calls kmem_cache_destroy().  So running some infiniband
config tool on one a single CPU dedicated to system tasks might interrupt
the rest of the 127 CPUs dedicated to some CPU intensive or latency
sensitive task.

I suspect there is a good chance that every line in the output of "git
grep kmem_cache_destroy linux/ | grep '\->'" has a similar scenario.

This patch attempts to rectify this issue by sending an IPI to flush the
per cpu objects back to the free lists only to CPUs that seem to have such
objects.

The check which CPU to IPI is racy but we don't care since asking a CPU
without per cpu objects to flush does no damage and as far as I can tell
the flush_all by itself is racy against allocs on remote CPUs anyway, so
if you required the flush_all to be determinstic, you had to arrange for
locking regardless.

Without this patch the following artificial test case:

$ cd /sys/kernel/slab
$ for DIR in *; do cat $DIR/alloc_calls > /dev/null; done

produces 166 IPIs on an cpuset isolated CPU. With it it produces none.

The code path of memory allocation failure for CPUMASK_OFFSTACK=y
config was tested using fault injection framework.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Avi Kivity <avi@redhat.com>
Cc: Michal Nazarewicz <mina86@mina86.org>
Cc: Kosaki Motohiro <kosaki.motohiro@gmail.com>
Cc: Milton Miller <miltonm@bga.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
add missing functions from 3.4, needed by '[slub 18d82c1] slub: only IPI CPUs that have per cpu obj to flush' (DerTeufel)

Change-Id: I14a40233b09aef9b22803fb0bdc8ef3b7f18bff3
slub: missing test for partial pages flush work in flush_all()

I found some kernel messages such as:

    SLUB raid5-md127: kmem_cache_destroy called for cache that still has objects.
    Pid: 6143, comm: mdadm Tainted: G           O 3.4.0-rc6+        #75
    Call Trace:
    kmem_cache_destroy+0x328/0x400
    free_conf+0x2d/0xf0 [raid456]
    stop+0x41/0x60 [raid456]
    md_stop+0x1a/0x60 [md_mod]
    do_md_stop+0x74/0x470 [md_mod]
    md_ioctl+0xff/0x11f0 [md_mod]
    blkdev_ioctl+0xd8/0x7a0
    block_ioctl+0x3b/0x40
    do_vfs_ioctl+0x96/0x560
    sys_ioctl+0x91/0xa0
    system_call_fastpath+0x16/0x1b

Then using kmemleak I found these messages:

    unreferenced object 0xffff8800b6db7380 (size 112):
      comm "mdadm", pid 5783, jiffies 4294810749 (age 90.589s)
      hex dump (first 32 bytes):
        01 01 db b6 ad 4e ad de ff ff ff ff ff ff ff ff  .....N..........
        ff ff ff ff ff ff ff ff 98 40 4a 82 ff ff ff ff  .........@J.....
      backtrace:
        kmemleak_alloc+0x21/0x50
        kmem_cache_alloc+0xeb/0x1b0
        kmem_cache_open+0x2f1/0x430
        kmem_cache_create+0x158/0x320
        setup_conf+0x649/0x770 [raid456]
        run+0x68b/0x840 [raid456]
        md_run+0x529/0x940 [md_mod]
        do_md_run+0x18/0xc0 [md_mod]
        md_ioctl+0xba8/0x11f0 [md_mod]
        blkdev_ioctl+0xd8/0x7a0
        block_ioctl+0x3b/0x40
        do_vfs_ioctl+0x96/0x560
        sys_ioctl+0x91/0xa0
        system_call_fastpath+0x16/0x1b

This bug was introduced by commit a8364d5555b ("slub: only IPI CPUs that
have per cpu obj to flush"), which did not include checks for per cpu
partial pages being present on a cpu.

Signed-off-by: majianpeng <majianpeng@gmail.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Tested-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slub: fix a memory leak in get_partial_node()

commit 02d7633fa567be7bf55a993b79d2a31b95ce2227 upstream.

In the case which is below,

1. acquire slab for cpu partial list
2. free object to it by remote cpu
3. page->freelist = t

then memory leak is occurred.

Change acquire_slab() not to zap freelist when it works for cpu partial list.
I think it is a sufficient solution for fixing a memory leak.

Below is output of 'slabinfo -r kmalloc-256'
when './perf stat -r 30 hackbench 50 process 4000 > /dev/null' is done.

***Vanilla***
Sizes (bytes)     Slabs              Debug                Memory
------------------------------------------------------------------------
Object :     256  Total  :     468   Sanity Checks : Off  Total: 3833856
SlabObj:     256  Full   :     111   Redzoning     : Off  Used : 2004992
SlabSiz:    8192  Partial:     302   Poisoning     : Off  Loss : 1828864
Loss   :       0  CpuSlab:      55   Tracking      : Off  Lalig:       0
Align  :       8  Objects:      32   Tracing       : Off  Lpadd:       0

***Patched***
Sizes (bytes)     Slabs              Debug                Memory
------------------------------------------------------------------------
Object :     256  Total  :     300   Sanity Checks : Off  Total: 2457600
SlabObj:     256  Full   :     204   Redzoning     : Off  Used : 2348800
SlabSiz:    8192  Partial:      33   Poisoning     : Off  Loss :  108800
Loss   :       0  CpuSlab:      63   Tracking      : Off  Lalig:       0
Align  :       8  Objects:      32   Tracing       : Off  Lpadd:       0

Total and loss number is the impact of this patch.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
slub: Use freelist instead of "object" in __slab_alloc

The variable "object" really refers to a list of objects that we
are handling.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Add frozen check in __slab_alloc

Verify that objects returned from __slab_alloc come from slab pages
in the correct state.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>