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SubjectRe: [rfc PATCH]slub: per cpu partial statistics change
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> Well the term releasing is unfortunate. per cpu partial pages can migrate
> to and from the per node partial list and become per cpu slabs under
> allocation.

Yes, The word is really not good here. How about of CPU_PARTIAL_UNFREEZE
since a unfreeze_cpu_partial() just called before ?
>
> > >> @@ -2465,9 +2466,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
> > >> * If we just froze the page then put it onto the
> > >> * per cpu partial list.
> > >> */
> > >> - if (new.frozen && !was_frozen)
> > >> + if (new.frozen && !was_frozen) {
> > >> put_cpu_partial(s, page, 1);
> > >> -
> > >> + stat(s, CPU_PARTIAL_FREE);
> > >
> > > cpu partial list filled with a partial page created from a fully allocated
> > > slab (which therefore was not on any list before).
> >
> >
> > Yes, but the counting is not new here. It just moved out of
> > put_cpu_partial().
>
> Ok but then you also added different accounting in put_cpu_partial.

Yes, I want to account the unfreeze_partials() actions in
put_cpu_partial(). The unfreezing accounting isn't conflict or repeat
with the cpu_partial_free accounting, since they are different actions
for the PCP.

According your above comments, how about the new patch with new
accounting name?
------------
>From bd2b79297b4550035b0b0ec16dd0f3008a3a76dc Mon Sep 17 00:00:00 2001
From: Alex Shi <alex.shi@intel.com>
Date: Fri, 3 Feb 2012 23:34:56 +0800
Subject: [PATCH] slub: per cpu partial statistics change
This patch split the cpu_partial_free into 2 parts: cpu_partial_node, PCP refilling
times from node partial; and same name cpu_partial_free, PCP refilling times in
slab_free slow path. A new statistic 'cpu_partial_unfreeze' is added to get PCP
unfreeze times. These info are useful when do PCP tunning.

The slabinfo.c code is unchanged, since cpu_partial_node is not on slow path.

Signed-off-by: Alex Shi <alex.shi@intel.com>
---
include/linux/slub_def.h | 6 ++++--
mm/slub.c | 12 +++++++++---
2 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index a32bcfd..2549483 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -21,7 +21,7 @@ enum stat_item {
FREE_FROZEN, /* Freeing to frozen slab */
FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
FREE_REMOVE_PARTIAL, /* Freeing removes last object */
- ALLOC_FROM_PARTIAL, /* Cpu slab acquired from partial list */
+ ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
ALLOC_SLAB, /* Cpu slab acquired from page allocator */
ALLOC_REFILL, /* Refill cpu slab from slab freelist */
ALLOC_NODE_MISMATCH, /* Switching cpu slab */
@@ -37,7 +37,9 @@ enum stat_item {
CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
- CPU_PARTIAL_FREE, /* USed cpu partial on free */
+ CPU_PARTIAL_FREE, /* Refill cpu partial on free */
+ CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
+ CPU_PARTIAL_UNFREEZE, /* Unfreeze cpu partial */
NR_SLUB_STAT_ITEMS };

struct kmem_cache_cpu {
diff --git a/mm/slub.c b/mm/slub.c
index 4907563..6ededd7 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1560,6 +1560,7 @@ static void *get_partial_node(struct kmem_cache *s,
} else {
page->freelist = t;
available = put_cpu_partial(s, page, 0);
+ stat(s, CPU_PARTIAL_NODE);
}
if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
break;
@@ -1973,6 +1974,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
local_irq_restore(flags);
pobjects = 0;
pages = 0;
+ stat(s, CPU_PARTIAL_UNFREEZE);
}
}

@@ -1984,7 +1986,6 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
page->next = oldpage;

} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
- stat(s, CPU_PARTIAL_FREE);
return pobjects;
}

@@ -2465,9 +2466,10 @@ static void __slab_free(struct kmem_cache *s, struct page *page,
* If we just froze the page then put it onto the
* per cpu partial list.
*/
- if (new.frozen && !was_frozen)
+ if (new.frozen && !was_frozen) {
put_cpu_partial(s, page, 1);
-
+ stat(s, CPU_PARTIAL_FREE);
+ }
/*
* The list lock was not taken therefore no list
* activity can be necessary.
@@ -5059,6 +5061,8 @@ STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
+STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
+STAT_ATTR(CPU_PARTIAL_UNFREEZE, cpu_partial_unfreeze);
#endif

static struct attribute *slab_attrs[] = {
@@ -5124,6 +5128,8 @@ static struct attribute *slab_attrs[] = {
&cmpxchg_double_cpu_fail_attr.attr,
&cpu_partial_alloc_attr.attr,
&cpu_partial_free_attr.attr,
+ &cpu_partial_node_attr.attr,
+ &cpu_partial_unfreeze_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
&failslab_attr.attr,
--
1.6.3.3



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