mm: slub: optimise the SLUB fast path to avoid pfmemalloc checks

This patch removes the check for pfmemalloc from the alloc hotpath and
puts the logic after the election of a new per cpu slab.  For a pfmemalloc
page we do not use the fast path but force the use of the slow path which
is also used for the debug case.

This has the side-effect of weakening pfmemalloc processing in the
following way;

1. A process that is allocating for network swap calls __slab_alloc.
   pfmemalloc_match is true so the freelist is loaded and c->freelist is
   now pointing to a pfmemalloc page.

2. A process that is attempting normal allocations calls slab_alloc,
   finds the pfmemalloc page on the freelist and uses it because it did
   not check pfmemalloc_match()

The patch allows non-pfmemalloc allocations to use pfmemalloc pages with
the kmalloc slabs being the most vunerable caches on the grounds they
are most likely to have a mix of pfmemalloc and !pfmemalloc requests. A
later patch will still protect the system as processes will get throttled
if the pfmemalloc reserves get depleted but performance will not degrade
as smoothly.

[mgorman@suse.de: Expanded changelog]
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slub: use free_page instead of put_page for freeing kmalloc allocation

When freeing objects, the slub allocator will most of the time free
empty pages by calling __free_pages(). But high-order kmalloc will be
diposed by means of put_page() instead. It makes no sense to call
put_page() in kernel pages that are provided by the object allocators,
so we shouldn't be doing this ourselves. Aside from the consistency
change, we don't change the flow too much. put_page()'s would call its
dtor function, which is __free_pages. We also already do all of the
Compound page tests ourselves, and the Mlock test we lose don't really
matter.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Acked-by: Christoph Lameter <cl@linux.com>
CC: David Rientjes <rientjes@google.com>
CC: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: Take node lock during object free checks

Only applies to scenarios where debugging is on:

Validation of slabs can currently occur while debugging
information is updated from the fast paths of the allocator.
This results in various races where we get false reports about
slab metadata not being in order.

This patch makes the fast paths take the node lock so that
serialization with slab validation will occur. Causes additional
slowdown in debug scenarios.

Reported-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub: reduce failure of this_cpu_cmpxchg in put_cpu_partial() after unfreezing

In current implementation, after unfreezing, we doesn't touch oldpage,
so it remain 'NOT NULL'. When we call this_cpu_cmpxchg()
with this old oldpage, this_cpu_cmpxchg() is mostly be failed.

We can change value of oldpage to NULL after unfreezing,
because unfreeze_partial() ensure that all the cpu partial slabs is removed
from cpu partial list. In this time, we could expect that
this_cpu_cmpxchg is mostly succeed.

Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Joonsoo Kim <js1304@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm/slub: Add debugging to verify correct cache use on kmem_cache_free()

Add additional debugging to check that the objects is actually from the cache
the caller claims. Doing so currently trips up some other debugging code. It
takes a lot to infer from that what was happening.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
[ penberg@kernel.org: Use pr_err() ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm/slub: Use kmem_cache for the kmem_cache structure

Do not use kmalloc() but kmem_cache_alloc() for the allocation
of the kmem_cache structures in slub.

Reviewed-by: Glauber Costa <glommer@parallels.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm: introduce __GFP_MEMALLOC to allow access to emergency reserves

__GFP_MEMALLOC will allow the allocation to disregard the watermarks, much
like PF_MEMALLOC.  It allows one to pass along the memalloc state in
object related allocation flags as opposed to task related flags, such as
sk->sk_allocation.  This removes the need for ALLOC_PFMEMALLOC as callers
using __GFP_MEMALLOC can get the ALLOC_NO_WATERMARK flag which is now
enough to identify allocations related to page reclaim.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

backported to Android Linux 3.4 by faux123
Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	include/linux/gfp.h
	mm/page_alloc.c
mm: micro-optimise slab to avoid a function call

Getting and putting objects in SLAB currently requires a function call but
the bulk of the work is related to PFMEMALLOC reserves which are only
consumed when network-backed storage is critical.  Use an inline function
to determine if the function call is required.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: David Miller <davem@davemloft.net>
Cc: Neil Brown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Eric B Munson <emunson@mgebm.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
slab: do not call compound_head() in page_get_cache()

page_get_cache() does not need to call compound_head(), as its unique
caller virt_to_slab() already makes sure to return a head page.

Additionally, removing the compound_head() call makes page_get_cache()
consistent with page_get_slab().

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm, slab: remove page_get_cache

page_get_cache() isn't called from anything, so remove it.

Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
mm, slab: lock the correct nodelist after reenabling irqs

cache_grow() can reenable irqs so the cpu (and node) can change, so ensure
that we take list_lock on the correct nodelist.

This fixes an issue with commit 072bb0aa5e06 ("mm: sl[au]b: add
knowledge of PFMEMALLOC reserve pages") where list_lock for the wrong
node was taken after growing the cache.

Reported-and-tested-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm: Fix build warning in kmem_cache_create()

The label oops is used in CONFIG_DEBUG_VM ifdef block and is defined
outside ifdef CONFIG_DEBUG_VM block. This results in the following
build warning when built with CONFIG_DEBUG_VM disabled. Fix to move
label oops definition to inside a CONFIG_DEBUG_VM block.

mm/slab_common.c: In function ‘kmem_cache_create’:
mm/slab_common.c:101:1: warning: label ‘oops’ defined but not used
[-Wunused-label]

Signed-off-by: Shuah Khan <shuah.khan@hp.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Paul Reioux <reioux@gmail.com>

Conflicts:
	mm/slab_common.c