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Commit ac2b898c authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
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[PATCH] slab: Remove SLAB_NO_REAP option 



SLAB_NO_REAP is documented as an option that will cause this slab not to be
reaped under memory pressure.  However, that is not what happens.  The only
thing that SLAB_NO_REAP controls at the moment is the reclaim of the unused
slab elements that were allocated in batch in cache_reap().  Cache_reap()
is run every few seconds independently of memory pressure.

Could we remove the whole thing?  Its only used by three slabs anyways and
I cannot find a reason for having this option.

There is an additional problem with SLAB_NO_REAP.  If set then the recovery
of objects from alien caches is switched off.  Objects not freed on the
same node where they were initially allocated will only be reused if a
certain amount of objects accumulates from one alien node (not very likely)
or if the cache is explicitly shrunk.  (Strangely __cache_shrink does not
check for SLAB_NO_REAP)

Getting rid of SLAB_NO_REAP fixes the problems with alien cache freeing.

Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 911851e6

drivers/scsi/iscsi_tcp.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -3639,7 +3639,7 @@ iscsi_tcp_init(void) 




	taskcache = kmem_cache_create("iscsi_taskcache",

	taskcache = kmem_cache_create("iscsi_taskcache",

			sizeof(struct iscsi_data_task), 0,

			sizeof(struct iscsi_data_task), 0,

			SLAB_HWCACHE_ALIGN | SLAB_NO_REAP, NULL, NULL);

			SLAB_HWCACHE_ALIGN, NULL, NULL);

	if (!taskcache)

	if (!taskcache)

		return -ENOMEM;

		return -ENOMEM;

fs/ocfs2/super.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -959,7 +959,7 @@ static int ocfs2_initialize_mem_caches(void) 
	ocfs2_lock_cache = kmem_cache_create("ocfs2_lock",

	ocfs2_lock_cache = kmem_cache_create("ocfs2_lock",

					     sizeof(struct ocfs2_journal_lock),

					     sizeof(struct ocfs2_journal_lock),

					     0,

					     0,

					     SLAB_NO_REAP|SLAB_HWCACHE_ALIGN,

					     SLAB_HWCACHE_ALIGN,

					     NULL, NULL);

					     NULL, NULL);

	if (!ocfs2_lock_cache)

	if (!ocfs2_lock_cache)

		return -ENOMEM;

		return -ENOMEM;

include/linux/slab.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -38,7 +38,6 @@ typedef struct kmem_cache kmem_cache_t; 
#define	SLAB_DEBUG_INITIAL	0x00000200UL	/* Call constructor (as verifier) */

#define	SLAB_DEBUG_INITIAL	0x00000200UL	/* Call constructor (as verifier) */

#define	SLAB_RED_ZONE		0x00000400UL	/* Red zone objs in a cache */

#define	SLAB_RED_ZONE		0x00000400UL	/* Red zone objs in a cache */

#define	SLAB_POISON		0x00000800UL	/* Poison objects */

#define	SLAB_POISON		0x00000800UL	/* Poison objects */

#define	SLAB_NO_REAP		0x00001000UL	/* never reap from the cache */

#define	SLAB_HWCACHE_ALIGN	0x00002000UL	/* align objs on a h/w cache lines */

#define	SLAB_HWCACHE_ALIGN	0x00002000UL	/* align objs on a h/w cache lines */

#define SLAB_CACHE_DMA		0x00004000UL	/* use GFP_DMA memory */

#define SLAB_CACHE_DMA		0x00004000UL	/* use GFP_DMA memory */

#define SLAB_MUST_HWCACHE_ALIGN	0x00008000UL	/* force alignment */

#define SLAB_MUST_HWCACHE_ALIGN	0x00008000UL	/* force alignment */

mm/slab.c

+2 −11
Original line number Original line Diff line number Diff line
@@ -170,12 +170,12 @@ 
#if DEBUG

#if DEBUG

# define CREATE_MASK	(SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \

# define CREATE_MASK	(SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \

			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \

			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \

			 SLAB_NO_REAP | SLAB_CACHE_DMA | \

			 SLAB_CACHE_DMA | \

			 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \

			 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \

			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \

			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \

			 SLAB_DESTROY_BY_RCU)

			 SLAB_DESTROY_BY_RCU)

#else

#else

# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \

# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | \

			 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \

			 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \

			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \

			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \

			 SLAB_DESTROY_BY_RCU)

			 SLAB_DESTROY_BY_RCU)
@@ -662,7 +662,6 @@ static struct kmem_cache cache_cache = { 
	.limit = BOOT_CPUCACHE_ENTRIES,

	.limit = BOOT_CPUCACHE_ENTRIES,

	.shared = 1,

	.shared = 1,

	.buffer_size = sizeof(struct kmem_cache),

	.buffer_size = sizeof(struct kmem_cache),

	.flags = SLAB_NO_REAP,

	.name = "kmem_cache",

	.name = "kmem_cache",

#if DEBUG

#if DEBUG

	.obj_size = sizeof(struct kmem_cache),

	.obj_size = sizeof(struct kmem_cache),
@@ -1848,9 +1847,6 @@ static void setup_cpu_cache(struct kmem_cache *cachep) 
 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check

 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check

 * for buffer overruns.

 * for buffer overruns.

 *

 *

 * %SLAB_NO_REAP - Don't automatically reap this cache when we're under

 * memory pressure.

 *

 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware

 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware

 * cacheline.  This can be beneficial if you're counting cycles as closely

 * cacheline.  This can be beneficial if you're counting cycles as closely

 * as davem.

 * as davem.
@@ -3584,10 +3580,6 @@ static void cache_reap(void *unused) 
		struct slab *slabp;

		struct slab *slabp;





		searchp = list_entry(walk, struct kmem_cache, next);

		searchp = list_entry(walk, struct kmem_cache, next);



		if (searchp->flags & SLAB_NO_REAP)

			goto next;



		check_irq_on();

		check_irq_on();





		l3 = searchp->nodelists[numa_node_id()];

		l3 = searchp->nodelists[numa_node_id()];
@@ -3635,7 +3627,6 @@ static void cache_reap(void *unused) 
		} while (--tofree > 0);

		} while (--tofree > 0);

next_unlock:

next_unlock:

		spin_unlock_irq(&l3->list_lock);

		spin_unlock_irq(&l3->list_lock);

next:

		cond_resched();

		cond_resched();

	}

	}

	check_irq_on();

	check_irq_on();