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Commit 78eb00cc authored by David Rientjes's avatar David Rientjes Committed by Pekka Enberg
Browse files

slub: allow stats to be cleared 



When collecting slub stats for particular workloads, it's necessary to
collect each statistic for all caches before the job is even started
because the counters are usually greater than zero just from boot and
initialization.

This allows a statistic to be cleared on each cpu by writing '0' to its
sysfs file.  This creates a baseline for statistics of interest before
the workload is started.

Setting a statistic to a particular value is not supported, so all values
written to these files other than '0' returns -EINVAL.

Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
parent 374576a8

Documentation/ABI/testing/sysfs-kernel-slab

+58 −51
Original line number Original line Diff line number Diff line
@@ -45,8 +45,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The alloc_fastpath file is read-only and specifies how many

		The alloc_fastpath file shows how many objects have been

		objects have been allocated using the fast path.

		allocated using the fast path.  It can be written to clear the

		current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/alloc_from_partial

What:		/sys/kernel/slab/cache/alloc_from_partial
@@ -55,9 +56,10 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The alloc_from_partial file is read-only and specifies how

		The alloc_from_partial file shows how many times a cpu slab has

		many times a cpu slab has been full and it has been refilled

		been full and it has been refilled by using a slab from the list

		by using a slab from the list of partially used slabs.

		of partially used slabs.  It can be written to clear the current

		count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/alloc_refill

What:		/sys/kernel/slab/cache/alloc_refill
@@ -66,9 +68,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The alloc_refill file is read-only and specifies how many

		The alloc_refill file shows how many times the per-cpu freelist

		times the per-cpu freelist was empty but there were objects

		was empty but there were objects available as the result of

		available as the result of remote cpu frees.

		remote cpu frees.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/alloc_slab

What:		/sys/kernel/slab/cache/alloc_slab
@@ -77,8 +79,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The alloc_slab file is read-only and specifies how many times

		The alloc_slab file is shows how many times a new slab had to

		a new slab had to be allocated from the page allocator.

		be allocated from the page allocator.  It can be written to

		clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/alloc_slowpath

What:		/sys/kernel/slab/cache/alloc_slowpath
@@ -87,9 +90,10 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The alloc_slowpath file is read-only and specifies how many

		The alloc_slowpath file shows how many objects have been

		objects have been allocated using the slow path because of a

		allocated using the slow path because of a refill or

		refill or allocation from a partial or new slab.

		allocation from a partial or new slab.  It can be written to

		clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/cache_dma

What:		/sys/kernel/slab/cache/cache_dma
@@ -117,10 +121,11 @@ KernelVersion: 2.6.31 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file cpuslab_flush is read-only and specifies how many

		The file cpuslab_flush shows how many times a cache's cpu slabs

		times a cache's cpu slabs have been flushed as the result of

		have been flushed as the result of destroying or shrinking a

		destroying or shrinking a cache, a cpu going offline, or as

		cache, a cpu going offline, or as the result of forcing an

		the result of forcing an allocation from a certain node.

		allocation from a certain node.  It can be written to clear the

		current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/ctor

What:		/sys/kernel/slab/cache/ctor
@@ -139,8 +144,8 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file deactivate_empty is read-only and specifies how many

		The deactivate_empty file shows how many times an empty cpu slab

		times an empty cpu slab was deactivated.

		was deactivated.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/deactivate_full

What:		/sys/kernel/slab/cache/deactivate_full
@@ -149,8 +154,8 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file deactivate_full is read-only and specifies how many

		The deactivate_full file shows how many times a full cpu slab

		times a full cpu slab was deactivated.

		was deactivated.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/deactivate_remote_frees

What:		/sys/kernel/slab/cache/deactivate_remote_frees
@@ -159,9 +164,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file deactivate_remote_frees is read-only and specifies how

		The deactivate_remote_frees file shows how many times a cpu slab

		many times a cpu slab has been deactivated and contained free

		has been deactivated and contained free objects that were freed

		objects that were freed remotely.

		remotely.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/deactivate_to_head

What:		/sys/kernel/slab/cache/deactivate_to_head
@@ -170,9 +175,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file deactivate_to_head is read-only and specifies how

		The deactivate_to_head file shows how many times a partial cpu

		many times a partial cpu slab was deactivated and added to the

		slab was deactivated and added to the head of its node's partial

		head of its node's partial list.

		list.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/deactivate_to_tail

What:		/sys/kernel/slab/cache/deactivate_to_tail
@@ -181,9 +186,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file deactivate_to_tail is read-only and specifies how

		The deactivate_to_tail file shows how many times a partial cpu

		many times a partial cpu slab was deactivated and added to the

		slab was deactivated and added to the tail of its node's partial

		tail of its node's partial list.

		list.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/destroy_by_rcu

What:		/sys/kernel/slab/cache/destroy_by_rcu
@@ -201,9 +206,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file free_add_partial is read-only and specifies how many

		The free_add_partial file shows how many times an object has

		times an object has been freed in a full slab so that it had to

		been freed in a full slab so that it had to added to its node's

		added to its node's partial list.

		partial list.  It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/free_calls

What:		/sys/kernel/slab/cache/free_calls
@@ -222,9 +227,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The free_fastpath file is read-only and specifies how many

		The free_fastpath file shows how many objects have been freed

		objects have been freed using the fast path because it was an

		using the fast path because it was an object from the cpu slab.

		object from the cpu slab.

		It can be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/free_frozen

What:		/sys/kernel/slab/cache/free_frozen
@@ -233,9 +238,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The free_frozen file is read-only and specifies how many

		The free_frozen file shows how many objects have been freed to

		objects have been freed to a frozen slab (i.e. a remote cpu

		a frozen slab (i.e. a remote cpu slab).  It can be written to

		slab).

		clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/free_remove_partial

What:		/sys/kernel/slab/cache/free_remove_partial
@@ -244,9 +249,10 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file free_remove_partial is read-only and specifies how

		The free_remove_partial file shows how many times an object has

		many times an object has been freed to a now-empty slab so

		been freed to a now-empty slab so that it had to be removed from

		that it had to be removed from its node's partial list.

		its node's partial list.  It can be written to clear the current

		count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/free_slab

What:		/sys/kernel/slab/cache/free_slab
@@ -255,8 +261,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The free_slab file is read-only and specifies how many times an

		The free_slab file shows how many times an empty slab has been

		empty slab has been freed back to the page allocator.

		freed back to the page allocator.  It can be written to clear

		the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/free_slowpath

What:		/sys/kernel/slab/cache/free_slowpath
@@ -265,9 +272,9 @@ KernelVersion: 2.6.25 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The free_slowpath file is read-only and specifies how many

		The free_slowpath file shows how many objects have been freed

		objects have been freed using the slow path (i.e. to a full or

		using the slow path (i.e. to a full or partial slab).  It can

		partial slab).

		be written to clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/hwcache_align

What:		/sys/kernel/slab/cache/hwcache_align
@@ -346,10 +353,10 @@ KernelVersion: 2.6.26 
Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

Contact:	Pekka Enberg <penberg@cs.helsinki.fi>,

		Christoph Lameter <cl@linux-foundation.org>

		Christoph Lameter <cl@linux-foundation.org>

Description:

Description:

		The file order_fallback is read-only and specifies how many

		The order_fallback file shows how many times an allocation of a

		times an allocation of a new slab has not been possible at the

		new slab has not been possible at the cache's order and instead

		cache's order and instead fallen back to its minimum possible

		fallen back to its minimum possible order.  It can be written to

		order.

		clear the current count.

		Available when CONFIG_SLUB_STATS is enabled.

		Available when CONFIG_SLUB_STATS is enabled.





What:		/sys/kernel/slab/cache/partial

What:		/sys/kernel/slab/cache/partial

mm/slub.c

+17 −1
Original line number Original line Diff line number Diff line
@@ -4371,12 +4371,28 @@ static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si) 
	return len + sprintf(buf + len, "\n");

	return len + sprintf(buf + len, "\n");

}

}





static void clear_stat(struct kmem_cache *s, enum stat_item si)

{

	int cpu;



	for_each_online_cpu(cpu)

		get_cpu_slab(s, cpu)->stat[si] = 0;

}



#define STAT_ATTR(si, text) 					\

#define STAT_ATTR(si, text) 					\

static ssize_t text##_show(struct kmem_cache *s, char *buf)	\

static ssize_t text##_show(struct kmem_cache *s, char *buf)	\

{								\

{								\

	return show_stat(s, buf, si);				\

	return show_stat(s, buf, si);				\

}								\

}								\

SLAB_ATTR_RO(text);						\

static ssize_t text##_store(struct kmem_cache *s,		\

				const char *buf, size_t length)	\

{								\

	if (buf[0] != '0')					\

		return -EINVAL;					\

	clear_stat(s, si);					\

	return length;						\

}								\

SLAB_ATTR(text);						\





STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);

STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);

STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);

STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);