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2012-12-18memcg: add comments clarifying aspects of cache attribute propagationGlauber Costa
This patch clarifies two aspects of cache attribute propagation. First, the expected context for the for_each_memcg_cache macro in memcontrol.h. The usages already in the codebase are safe. In mm/slub.c, it is trivially safe because the lock is acquired right before the loop. In mm/slab.c, it is less so: the lock is acquired by an outer function a few steps back in the stack, so a VM_BUG_ON() is added to make sure it is indeed safe. A comment is also added to detail why we are returning the value of the parent cache and ignoring the children's when we propagate the attributes. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18slab: propagate tunable valuesGlauber Costa
SLAB allows us to tune a particular cache behavior with tunables. When creating a new memcg cache copy, we'd like to preserve any tunables the parent cache already had. This could be done by an explicit call to do_tune_cpucache() after the cache is created. But this is not very convenient now that the caches are created from common code, since this function is SLAB-specific. Another method of doing that is taking advantage of the fact that do_tune_cpucache() is always called from enable_cpucache(), which is called at cache initialization. We can just preset the values, and then things work as expected. It can also happen that a root cache has its tunables updated during normal system operation. In this case, we will propagate the change to all caches that are already active. This change will require us to move the assignment of root_cache in memcg_params a bit earlier. We need this to be already set - which memcg_kmem_register_cache will do - when we reach __kmem_cache_create() Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18memcg: destroy memcg cachesGlauber Costa
Implement destruction of memcg caches. Right now, only caches where our reference counter is the last remaining are deleted. If there are any other reference counters around, we just leave the caches lying around until they go away. When that happens, a destruction function is called from the cache code. Caches are only destroyed in process context, so we queue them up for later processing in the general case. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18sl[au]b: allocate objects from memcg cacheGlauber Costa
We are able to match a cache allocation to a particular memcg. If the task doesn't change groups during the allocation itself - a rare event, this will give us a good picture about who is the first group to touch a cache page. This patch uses the now available infrastructure by calling memcg_kmem_get_cache() before all the cache allocations. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18sl[au]b: always get the cache from its page in kmem_cache_free()Glauber Costa
struct page already has this information. If we start chaining caches, this information will always be more trustworthy than whatever is passed into the function. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-18slab: annotate on-slab caches nodelist locksGlauber Costa
We currently provide lockdep annotation for kmalloc caches, and also caches that have SLAB_DEBUG_OBJECTS enabled. The reason for this is that we can quite frequently nest in the l3->list_lock lock, which is not something trivial to avoid. My proposal with this patch, is to extend this to caches whose slab management object lives within the slab as well ("on_slab"). The need for this arose in the context of testing kmemcg-slab patches. With such patchset, we can have per-memcg kmalloc caches. So the same path that led to nesting between kmalloc caches will could then lead to in-memcg nesting. Because they are not annotated, lockdep will trigger. Signed-off-by: Glauber Costa <glommer@parallels.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Frederic Weisbecker <fweisbec@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: JoonSoo Kim <js1304@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Michal Hocko <mhocko@suse.cz> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Rik van Riel <riel@redhat.com> Cc: Suleiman Souhlal <suleiman@google.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11mm/sl[aou]b: Common alignment codeChristoph Lameter
Extract the code to do object alignment from the allocators. Do the alignment calculations in slab_common so that the __kmem_cache_create functions of the allocators do not have to deal with alignment. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11slab: Use the new create_boot_cache function to simplify bootstrapChristoph Lameter
Simplify setup and reduce code in kmem_cache_init(). This allows us to get rid of initarray_cache as well as the manual setup code for the kmem_cache and kmem_cache_node arrays during bootstrap. We introduce a new bootstrap state "PARTIAL" for slab that signals the creation of a kmem_cache boot cache. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-12-11mm, sl[au]b: create common functions for boot slab creationChristoph Lameter
Use a special function to create kmalloc caches and use that function in SLAB and SLUB. Acked-by: Joonsoo Kim <js1304@gmail.com> 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>
2012-12-11slab: Simplify bootstrapChristoph Lameter
The nodelists field in kmem_cache is pointing to the first unused object in the array field when bootstrap is complete. A problem with the current approach is that the statically sized kmem_cache structure use on boot can only contain NR_CPUS entries. If the number of nodes plus the number of cpus is greater then we would overwrite memory following the kmem_cache_boot definition. Increase the size of the array field to ensure that also the node pointers fit into the array field. Once we do that we no longer need the kmem_cache_nodelists array and we can then also use that structure elsewhere. Acked-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-11-15mm: fix slab.c kernel-doc warningsRandy Dunlap
Fix new kernel-doc warnings in mm/slab.c: Warning(mm/slab.c:2358): No description found for parameter 'cachep' Warning(mm/slab.c:2358): Excess function parameter 'name' description in '__kmem_cache_create' Warning(mm/slab.c:2358): Excess function parameter 'size' description in '__kmem_cache_create' Warning(mm/slab.c:2358): Excess function parameter 'align' description in '__kmem_cache_create' Warning(mm/slab.c:2358): Excess function parameter 'ctor' description in '__kmem_cache_create' Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-31slab: Ignore internal flags in cache creationGlauber Costa
Some flags are used internally by the allocators for management purposes. One example of that is the CFLGS_OFF_SLAB flag that slab uses to mark that the metadata for that cache is stored outside of the slab. No cache should ever pass those as a creation flags. We can just ignore this bit if it happens to be passed (such as when duplicating a cache in the kmem memcg patches). Because such flags can vary from allocator to allocator, we allow them to make their own decisions on that, defining SLAB_AVAILABLE_FLAGS with all flags that are valid at creation time. Allocators that doesn't have any specific flag requirement should define that to mean all flags. Common code will mask out all flags not belonging to that set. Acked-by: Christoph Lameter <cl@linux.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-31mm/sl[aou]b: Move common kmem_cache_size() to slab.hEzequiel Garcia
This function is identically defined in all three allocators and it's trivial to move it to slab.h Since now it's static, inline, header-defined function this patch also drops the EXPORT_SYMBOL tag. Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24sl[au]b: Process slabinfo_show in common codeGlauber Costa
With all the infrastructure in place, we can now have slabinfo_show done from slab_common.c. A cache-specific function is called to grab information about the cache itself, since that is still heavily dependent on the implementation. But with the values produced by it, all the printing and handling is done from common code. Signed-off-by: Glauber Costa <glommer@parallels.com> CC: Christoph Lameter <cl@linux.com> CC: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24mm/sl[au]b: Move print_slabinfo_header to slab_common.cGlauber Costa
The header format is highly similar between slab and slub. The main difference lays in the fact that slab may optionally have statistics added here in case of CONFIG_SLAB_DEBUG, while the slub will stick them somewhere else. By making sure that information conditionally lives inside a globally-visible CONFIG_DEBUG_SLAB switch, we can move the header printing to a common location. Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Christoph Lameter <cl@linux.com> CC: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-24mm/sl[au]b: Move slabinfo processing to slab_common.cGlauber Costa
This patch moves all the common machinery to slabinfo processing to slab_common.c. We can do better by noticing that the output is heavily common, and having the allocators to just provide finished information about this. But after this first step, this can be done easier. Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Christoph Lameter <cl@linux.com> CC: David Rientjes <rientjes@google.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-07Merge branch 'slab/for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux Pull SLAB changes from Pekka Enberg: "New and noteworthy: * More SLAB allocator unification patches from Christoph Lameter and others. This paves the way for slab memcg patches that hopefully will land in v3.8. * SLAB tracing improvements from Ezequiel Garcia. * Kernel tainting upon SLAB corruption from Dave Jones. * Miscellanous SLAB allocator bug fixes and improvements from various people." * 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux: (43 commits) slab: Fix build failure in __kmem_cache_create() slub: init_kmem_cache_cpus() and put_cpu_partial() can be static mm/slab: Fix kmem_cache_alloc_node_trace() declaration Revert "mm/slab: Fix kmem_cache_alloc_node_trace() declaration" mm, slob: fix build breakage in __kmalloc_node_track_caller mm/slab: Fix kmem_cache_alloc_node_trace() declaration mm/slab: Fix typo _RET_IP -> _RET_IP_ mm, slub: Rename slab_alloc() -> slab_alloc_node() to match SLAB mm, slab: Rename __cache_alloc() -> slab_alloc() mm, slab: Match SLAB and SLUB kmem_cache_alloc_xxx_trace() prototype mm, slab: Replace 'caller' type, void* -> unsigned long mm, slob: Add support for kmalloc_track_caller() mm, slab: Remove silly function slab_buffer_size() mm, slob: Use NUMA_NO_NODE instead of -1 mm, sl[au]b: Taint kernel when we detect a corrupted slab slab: Only define slab_error for DEBUG slab: fix the DEADLOCK issue on l3 alien lock slub: Zero initial memory segment for kmem_cache and kmem_cache_node Revert "mm/sl[aou]b: Move sysfs_slab_add to common" mm/sl[aou]b: Move kmem_cache refcounting to common code ...
2012-10-03Merge branch 'slab/tracing' into slab/for-linusPekka Enberg
2012-10-03Merge branch 'slab/common-for-cgroups' into slab/for-linusPekka Enberg
Fix up a trivial conflict with NUMA_NO_NODE cleanups. Conflicts: mm/slob.c Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-03Merge branch 'slab/next' into slab/for-linusPekka Enberg
2012-10-03slab: Fix build failure in __kmem_cache_create()Tetsuo Handa
Fix build failure with CONFIG_DEBUG_SLAB=y && CONFIG_DEBUG_PAGEALLOC=y caused by commit 8a13a4cc "mm/sl[aou]b: Shrink __kmem_cache_create() parameter lists". mm/slab.c: In function '__kmem_cache_create': mm/slab.c:2474: error: 'align' undeclared (first use in this function) mm/slab.c:2474: error: (Each undeclared identifier is reported only once mm/slab.c:2474: error: for each function it appears in.) make[1]: *** [mm/slab.o] Error 1 make: *** [mm] Error 2 Acked-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-10-02Merge branch 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wqLinus Torvalds
Pull workqueue changes from Tejun Heo: "This is workqueue updates for v3.7-rc1. A lot of activities this round including considerable API and behavior cleanups. * delayed_work combines a timer and a work item. The handling of the timer part has always been a bit clunky leading to confusing cancelation API with weird corner-case behaviors. delayed_work is updated to use new IRQ safe timer and cancelation now works as expected. * Another deficiency of delayed_work was lack of the counterpart of mod_timer() which led to cancel+queue combinations or open-coded timer+work usages. mod_delayed_work[_on]() are added. These two delayed_work changes make delayed_work provide interface and behave like timer which is executed with process context. * A work item could be executed concurrently on multiple CPUs, which is rather unintuitive and made flush_work() behavior confusing and half-broken under certain circumstances. This problem doesn't exist for non-reentrant workqueues. While non-reentrancy check isn't free, the overhead is incurred only when a work item bounces across different CPUs and even in simulated pathological scenario the overhead isn't too high. All workqueues are made non-reentrant. This removes the distinction between flush_[delayed_]work() and flush_[delayed_]_work_sync(). The former is now as strong as the latter and the specified work item is guaranteed to have finished execution of any previous queueing on return. * In addition to the various bug fixes, Lai redid and simplified CPU hotplug handling significantly. * Joonsoo introduced system_highpri_wq and used it during CPU hotplug. There are two merge commits - one to pull in IRQ safe timer from tip/timers/core and the other to pull in CPU hotplug fixes from wq/for-3.6-fixes as Lai's hotplug restructuring depended on them." Fixed a number of trivial conflicts, but the more interesting conflicts were silent ones where the deprecated interfaces had been used by new code in the merge window, and thus didn't cause any real data conflicts. Tejun pointed out a few of them, I fixed a couple more. * 'for-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: (46 commits) workqueue: remove spurious WARN_ON_ONCE(in_irq()) from try_to_grab_pending() workqueue: use cwq_set_max_active() helper for workqueue_set_max_active() workqueue: introduce cwq_set_max_active() helper for thaw_workqueues() workqueue: remove @delayed from cwq_dec_nr_in_flight() workqueue: fix possible stall on try_to_grab_pending() of a delayed work item workqueue: use hotcpu_notifier() for workqueue_cpu_down_callback() workqueue: use __cpuinit instead of __devinit for cpu callbacks workqueue: rename manager_mutex to assoc_mutex workqueue: WORKER_REBIND is no longer necessary for idle rebinding workqueue: WORKER_REBIND is no longer necessary for busy rebinding workqueue: reimplement idle worker rebinding workqueue: deprecate __cancel_delayed_work() workqueue: reimplement cancel_delayed_work() using try_to_grab_pending() workqueue: use mod_delayed_work() instead of __cancel + queue workqueue: use irqsafe timer for delayed_work workqueue: clean up delayed_work initializers and add missing one workqueue: make deferrable delayed_work initializer names consistent workqueue: cosmetic whitespace updates for macro definitions workqueue: deprecate system_nrt[_freezable]_wq workqueue: deprecate flush[_delayed]_work_sync() ...
2012-09-29Revert "mm/slab: Fix kmem_cache_alloc_node_trace() declaration"Pekka Enberg
This reverts commit 1e5965bf1f018cc30a4659fa3f1a40146e4276f6. Ezequiel Garcia has a better fix.
2012-09-25mm/slab: Fix kmem_cache_alloc_node_trace() declarationEzequiel Garcia
The bug was introduced in commit 4052147c0afa ("mm, slab: Match SLAB and SLUB kmem_cache_alloc_xxx_trace() prototype"). Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25mm/slab: Fix typo _RET_IP -> _RET_IP_Ezequiel Garcia
The bug was introduced by commit 7c0cb9c64f83 ("mm, slab: Replace 'caller' type, void* -> unsigned long"). Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25mm, slab: Rename __cache_alloc() -> slab_alloc()Ezequiel Garcia
This patch does not fix anything and its only goal is to produce common code between SLAB and SLUB. Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25mm, slab: Match SLAB and SLUB kmem_cache_alloc_xxx_trace() prototypeEzequiel Garcia
This long (seemingly unnecessary) patch does not fix anything and its only goal is to produce common code between SLAB and SLUB. Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25mm, slab: Replace 'caller' type, void* -> unsigned longEzequiel Garcia
This allows to use _RET_IP_ instead of builtin_address(0), thus achiveing implementation consistency in all three allocators. Though maybe a nitpick, the real goal behind this patch is to be able to obtain common code between SLAB and SLUB. Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-25mm, slab: Remove silly function slab_buffer_size()Ezequiel Garcia
This function is seldom used, and can be simply replaced with cachep->size. Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-19mm, sl[au]b: Taint kernel when we detect a corrupted slabDave Jones
It doesn't seem worth adding a new taint flag for this, so just re-use the one from 'bad page' Acked-by: Christoph Lameter <cl@linux.com> # SLUB Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-19slab: Only define slab_error for DEBUGChristoph Lameter
On Tue, 11 Sep 2012, Stephen Rothwell wrote: > After merging the final tree, today's linux-next build (sparc64 defconfig) > produced this warning: > > mm/slab.c:808:13: warning: '__slab_error' defined but not used [-Wunused-function] > > Introduced by commit 945cf2b6199b ("mm/sl[aou]b: Extract a common > function for kmem_cache_destroy"). All uses of slab_error() are now > guarded by DEBUG. There is no use case left for slab builds without DEBUG. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-17slab: fix starting index for finding another objectJoonsoo Kim
In array cache, there is a object at index 0, check it. Signed-off-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-17slab: do ClearSlabPfmemalloc() for all pages of slabMel Gorman
Right now, we call ClearSlabPfmemalloc() for first page of slab when we clear SlabPfmemalloc flag. This is fine for most swap-over-network use cases as it is expected that order-0 pages are in use. Unfortunately it is possible that that __ac_put_obj() checks SlabPfmemalloc on a tail page and while this is harmless, it is sloppy. This patch ensures that the head page is always used. This problem was originally identified by Joonsoo Kim. [js1304@gmail.com: Original implementation and problem identification] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Joonsoo Kim <js1304@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-09-11slab: fix the DEADLOCK issue on l3 alien lockMichael Wang
DEADLOCK will be report while running a kernel with NUMA and LOCKDEP enabled, the process of this fake report is: kmem_cache_free() //free obj in cachep -> cache_free_alien() //acquire cachep's l3 alien lock -> __drain_alien_cache() -> free_block() -> slab_destroy() -> kmem_cache_free() //free slab in cachep->slabp_cache -> cache_free_alien() //acquire cachep->slabp_cache's l3 alien lock Since the cachep and cachep->slabp_cache's l3 alien are in the same lock class, fake report generated. This should not happen since we already have init_lock_keys() which will reassign the lock class for both l3 list and l3 alien. However, init_lock_keys() was invoked at a wrong position which is before we invoke enable_cpucache() on each cache. Since until set slab_state to be FULL, we won't invoke enable_cpucache() on caches to build their l3 alien while creating them, so although we invoked init_lock_keys(), the l3 alien lock class won't change since we don't have them until invoked enable_cpucache() later. This patch will invoke init_lock_keys() after we done enable_cpucache() instead of before to avoid the fake DEADLOCK report. Michael traced the problem back to a commit in release 3.0.0: commit 30765b92ada267c5395fc788623cb15233276f5c Author: Peter Zijlstra <peterz@infradead.org> Date: Thu Jul 28 23:22:56 2011 +0200 slab, lockdep: Annotate the locks before using them Fernando found we hit the regular OFF_SLAB 'recursion' before we annotate the locks, cure this. The relevant portion of the stack-trace: > [ 0.000000] [<c085e24f>] rt_spin_lock+0x50/0x56 > [ 0.000000] [<c04fb406>] __cache_free+0x43/0xc3 > [ 0.000000] [<c04fb23f>] kmem_cache_free+0x6c/0xdc > [ 0.000000] [<c04fb2fe>] slab_destroy+0x4f/0x53 > [ 0.000000] [<c04fb396>] free_block+0x94/0xc1 > [ 0.000000] [<c04fc551>] do_tune_cpucache+0x10b/0x2bb > [ 0.000000] [<c04fc8dc>] enable_cpucache+0x7b/0xa7 > [ 0.000000] [<c0bd9d3c>] kmem_cache_init_late+0x1f/0x61 > [ 0.000000] [<c0bba687>] start_kernel+0x24c/0x363 > [ 0.000000] [<c0bba0ba>] i386_start_kernel+0xa9/0xaf Reported-by: Fernando Lopez-Lezcano <nando@ccrma.Stanford.EDU> Acked-by: Pekka Enberg <penberg@kernel.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1311888176.2617.379.camel@laptop Signed-off-by: Ingo Molnar <mingo@elte.hu> The commit moved init_lock_keys() before we build up the alien, so we failed to reclass it. Cc: <stable@vger.kernel.org> # 3.0+ Acked-by: Christoph Lameter <cl@linux.com> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Move kmem_cache refcounting to common codeChristoph Lameter
Get rid of the refcount stuff in the allocators and do that part of kmem_cache management in the common code. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Shrink __kmem_cache_create() parameter listsChristoph Lameter
Do the initial settings of the fields in common code. This will allow us to push more processing into common code later and improve readability. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Move kmem_cache allocations into common codeChristoph Lameter
Shift the allocations to common code. That way the allocation and freeing of the kmem_cache structures is handled by common code. Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Get rid of __kmem_cache_destroyChristoph Lameter
What is done there can be done in __kmem_cache_shutdown. This affects RCU handling somewhat. On rcu free all slab allocators do not refer to other management structures than the kmem_cache structure. Therefore these other structures can be freed before the rcu deferred free to the page allocator occurs. Reviewed-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Move freeing of kmem_cache structure to common codeChristoph Lameter
The freeing action is basically the same in all slab allocators. Move to the common kmem_cache_destroy() function. Reviewed-by: Glauber Costa <glommer@parallels.com> Reviewed-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Use "kmem_cache" name for slab cache with kmem_cache structChristoph Lameter
Make all allocators use the "kmem_cache" slabname for the "kmem_cache" structure. Reviewed-by: Glauber Costa <glommer@parallels.com> Reviewed-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Extract a common function for kmem_cache_destroyChristoph Lameter
kmem_cache_destroy does basically the same in all allocators. Extract common code which is easy since we already have common mutex handling. Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-09-05mm/sl[aou]b: Move list_add() to slab_common.cChristoph Lameter
Move the code to append the new kmem_cache to the list of slab caches to the kmem_cache_create code in the shared code. This is possible now since the acquisition of the mutex was moved into kmem_cache_create(). Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Glauber Costa <glommer@parallels.com> Reviewed-by: Joonsoo Kim <js1304@gmail.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
2012-08-29mm, slab: lock the correct nodelist after reenabling irqsDavid Rientjes
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>
2012-08-21workqueue: make deferrable delayed_work initializer names consistentTejun Heo
Initalizers for deferrable delayed_work are confused. * __DEFERRED_WORK_INITIALIZER() * DECLARE_DEFERRED_WORK() * INIT_DELAYED_WORK_DEFERRABLE() Rename them to * __DEFERRABLE_WORK_INITIALIZER() * DECLARE_DEFERRABLE_WORK() * INIT_DEFERRABLE_WORK() This patch doesn't cause any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org>
2012-08-17mm, slab: remove page_get_cacheDavid Rientjes
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>
2012-08-16slab: do not call compound_head() in page_get_cache()Michel Lespinasse
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>
2012-07-31mm: micro-optimise slab to avoid a function callMel Gorman
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>
2012-07-31mm: introduce __GFP_MEMALLOC to allow access to emergency reservesMel Gorman
__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>
2012-07-31mm: sl[au]b: add knowledge of PFMEMALLOC reserve pagesMel Gorman
When a user or administrator requires swap for their application, they create a swap partition and file, format it with mkswap and activate it with swapon. Swap over the network is considered as an option in diskless systems. The two likely scenarios are when blade servers are used as part of a cluster where the form factor or maintenance costs do not allow the use of disks and thin clients. The Linux Terminal Server Project recommends the use of the Network Block Device (NBD) for swap according to the manual at https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download There is also documentation and tutorials on how to setup swap over NBD at places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The nbd-client also documents the use of NBD as swap. Despite this, the fact is that a machine using NBD for swap can deadlock within minutes if swap is used intensively. This patch series addresses the problem. The core issue is that network block devices do not use mempools like normal block devices do. As the host cannot control where they receive packets from, they cannot reliably work out in advance how much memory they might need. Some years ago, Peter Zijlstra developed a series of patches that supported swap over an NFS that at least one distribution is carrying within their kernels. This patch series borrows very heavily from Peter's work to support swapping over NBD as a pre-requisite to supporting swap-over-NFS. The bulk of the complexity is concerned with preserving memory that is allocated from the PFMEMALLOC reserves for use by the network layer which is needed for both NBD and NFS. Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to preserve access to pages allocated under low memory situations to callers that are freeing memory. Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC reserves without setting PFMEMALLOC. Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves for later use by network packet processing. Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set. Patches 7-12 allows network processing to use PFMEMALLOC reserves when the socket has been marked as being used by the VM to clean pages. If packets are received and stored in pages that were allocated under low-memory situations and are unrelated to the VM, the packets are dropped. Patch 11 reintroduces __skb_alloc_page which the networking folk may object to but is needed in some cases to propogate pfmemalloc from a newly allocated page to an skb. If there is a strong objection, this patch can be dropped with the impact being that swap-over-network will be slower in some cases but it should not fail. Patch 13 is a micro-optimisation to avoid a function call in the common case. Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use PFMEMALLOC if necessary. Patch 15 notes that it is still possible for the PFMEMALLOC reserve to be depleted. To prevent this, direct reclaimers get throttled on a waitqueue if 50% of the PFMEMALLOC reserves are depleted. It is expected that kswapd and the direct reclaimers already running will clean enough pages for the low watermark to be reached and the throttled processes are woken up. Patch 16 adds a statistic to track how often processes get throttled Some basic performance testing was run using kernel builds, netperf on loopback for UDP and TCP, hackbench (pipes and sockets), iozone and sysbench. Each of them were expected to use the sl*b allocators reasonably heavily but there did not appear to be significant performance variances. For testing swap-over-NBD, a machine was booted with 2G of RAM with a swapfile backed by NBD. 8*NUM_CPU processes were started that create anonymous memory mappings and read them linearly in a loop. The total size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under memory pressure. Without the patches and using SLUB, the machine locks up within minutes and runs to completion with them applied. With SLAB, the story is different as an unpatched kernel run to completion. However, the patched kernel completed the test 45% faster. MICRO 3.5.0-rc2 3.5.0-rc2 vanilla swapnbd Unrecognised test vmscan-anon-mmap-write MMTests Statistics: duration Sys Time Running Test (seconds) 197.80 173.07 User+Sys Time Running Test (seconds) 206.96 182.03 Total Elapsed Time (seconds) 3240.70 1762.09 This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages Allocations of pages below the min watermark run a risk of the machine hanging due to a lack of memory. To prevent this, only callers who have PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are allowed to allocate with ALLOC_NO_WATERMARKS. Once they are allocated to a slab though, nothing prevents other callers consuming free objects within those slabs. This patch limits access to slab pages that were alloced from the PFMEMALLOC reserves. When this patch is applied, pages allocated from below the low watermark are returned with page->pfmemalloc set and it is up to the caller to determine how the page should be protected. SLAB restricts access to any page with page->pfmemalloc set to callers which are known to able to access the PFMEMALLOC reserve. If one is not available, an attempt is made to allocate a new page rather than use a reserve. SLUB is a bit more relaxed in that it only records if the current per-CPU page was allocated from PFMEMALLOC reserve and uses another partial slab if the caller does not have the necessary GFP or process flags. This was found to be sufficient in tests to avoid hangs due to SLUB generally maintaining smaller lists than SLAB. In low-memory conditions it does mean that !PFMEMALLOC allocators can fail a slab allocation even though free objects are available because they are being preserved for callers that are freeing pages. [a.p.zijlstra@chello.nl: Original implementation] [sebastian@breakpoint.cc: Correct order of page flag clearing] 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>
2012-07-09mm, sl[aou]b: Move kmem_cache_create mutex handling to common codeChristoph Lameter
Move the mutex handling into the common kmem_cache_create() function. Then we can also move more checks out of SLAB's kmem_cache_create() into the common code. Reviewed-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>