On Sat, 2011-12-03 at 04:02 +0800, Christoph Lameter wrote:
> On Fri, 2 Dec 2011, Eric Dumazet wrote:
>
> > netperf (loopback or ethernet) is a known stress test for slub, and your
> > patch removes code that might hurt netperf, but benefit real workload.
> >
> > Have you tried instead this far less intrusive solution ?
> >
> > if (tail == DEACTIVATE_TO_TAIL ||
> > page->inuse > page->objects / 4)
> > list_add_tail(&page->lru, &n->partial);
> > else
> > list_add(&page->lru, &n->partial);
>
> One could also move this logic to reside outside of the call to
> add_partial(). This is called mostly from __slab_free() so the logic could
> be put in there.
>
After pcp adding, add_partial just be used in put_cpu_partial ->
unfreeze_partial without debug setting. If we need to do change, guess
it's better in this function.
BTW
I collection some data with my PCP statistics patch. I will be very glad
if you like it.
[alexs@lkp-ne04 ~]$ sudo grep . /sys/kernel/slab/kmalloc-256/*
/sys/kernel/slab/kmalloc-256/alloc_from_partial:4955645
/sys/kernel/slab/kmalloc-256/alloc_from_pcp:6753981
...
/sys/kernel/slab/kmalloc-256/pcp_from_free:11743977
/sys/kernel/slab/kmalloc-256/pcp_from_node:5948883
...
/sys/kernel/slab/kmalloc-256/unfreeze_pcp:834262
--------------
>From aa754e20b81cb9f5ab63800a084858d25c18db31 Mon Sep 17 00:00:00 2001
From: Alex shi <alex.shi@xxxxxxxxx>
Date: Tue, 6 Dec 2011 01:49:16 +0800
Subject: [PATCH] slub: per cpu partial statistics collection
PCP statistics were not collected in detail now. Add and change some variables
for this.
changed:
cpu_partial_alloc --> alloc_from_pcp,
cpu_partial_free --> pcp_from_free, /* pcp refilled from slab free */
added:
pcp_from_node, /* pcp refilled from node partial */
unfreeze_pcp, /* unfreeze pcp */
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx>
---
include/linux/slub_def.h | 8 +++++---
mm/slub.c | 22 ++++++++++++++--------
tools/slub/slabinfo.c | 12 ++++++------
3 files changed, 25 insertions(+), 17 deletions(-)
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index a32bcfd..1c2669b 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 */
@@ -36,8 +36,10 @@ enum stat_item {
ORDER_FALLBACK, /* Number of times fallback was necessary */
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 */
+ ALLOC_FROM_PCP, /* Used cpu partial on alloc */
+ PCP_FROM_FREE, /* Fill cpu partial from free */
+ PCP_FROM_NODE, /* Fill cpu partial from node partial */
+ UNFREEZE_PCP, /* Unfreeze per cpu partial */
NR_SLUB_STAT_ITEMS };
struct kmem_cache_cpu {
diff --git a/mm/slub.c b/mm/slub.c
index ed3334d..5843846 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -1558,6 +1558,7 @@ static void *get_partial_node(struct kmem_cache *s,
} else {
page->freelist = t;
available = put_cpu_partial(s, page, 0);
+ stat(s, PCP_FROM_NODE);
}
if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
break;
@@ -1968,6 +1969,7 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
local_irq_restore(flags);
pobjects = 0;
pages = 0;
+ stat(s, UNFREEZE_PCP);
}
}
@@ -1979,7 +1981,6 @@ int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
page->next = oldpage;
} while (irqsafe_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
- stat(s, CPU_PARTIAL_FREE);
return pobjects;
}
@@ -2212,7 +2213,7 @@ new_slab:
c->page = c->partial;
c->partial = c->page->next;
c->node = page_to_nid(c->page);
- stat(s, CPU_PARTIAL_ALLOC);
+ stat(s, ALLOC_FROM_PCP);
c->freelist = NULL;
goto redo;
}
@@ -2448,9 +2449,10 @@ 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, PCP_FROM_FREE);
+ }
/*
* The list lock was not taken therefore no list
* activity can be necessary.
@@ -5032,8 +5034,10 @@ STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
STAT_ATTR(ORDER_FALLBACK, order_fallback);
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(ALLOC_FROM_PCP, alloc_from_pcp);
+STAT_ATTR(PCP_FROM_FREE, pcp_from_free);
+STAT_ATTR(PCP_FROM_NODE, pcp_from_node);
+STAT_ATTR(UNFREEZE_PCP, unfreeze_pcp);
#endif
static struct attribute *slab_attrs[] = {
@@ -5097,8 +5101,10 @@ static struct attribute *slab_attrs[] = {
&order_fallback_attr.attr,
&cmpxchg_double_fail_attr.attr,
&cmpxchg_double_cpu_fail_attr.attr,
- &cpu_partial_alloc_attr.attr,
- &cpu_partial_free_attr.attr,
+ &alloc_from_pcp_attr.attr,
+ &pcp_from_free_attr.attr,
+ &pcp_from_node_attr.attr,
+ &unfreeze_pcp_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
&failslab_attr.attr,
diff --git a/tools/slub/slabinfo.c b/tools/slub/slabinfo.c
index 164cbcf..d8f67f0 100644
--- a/tools/slub/slabinfo.c
+++ b/tools/slub/slabinfo.c
@@ -42,7 +42,7 @@ struct slabinfo {
unsigned long deactivate_remote_frees, order_fallback;
unsigned long cmpxchg_double_cpu_fail, cmpxchg_double_fail;
unsigned long alloc_node_mismatch, deactivate_bypass;
- unsigned long cpu_partial_alloc, cpu_partial_free;
+ unsigned long alloc_from_pcp, pcp_from_free;
int numa[MAX_NODES];
int numa_partial[MAX_NODES];
} slabinfo[MAX_SLABS];
@@ -457,9 +457,9 @@ static void slab_stats(struct slabinfo *s)
s->free_remove_partial * 100 / total_free);
printf("Cpu partial list %8lu %8lu %3lu %3lu\n",
- s->cpu_partial_alloc, s->cpu_partial_free,
- s->cpu_partial_alloc * 100 / total_alloc,
- s->cpu_partial_free * 100 / total_free);
+ s->alloc_from_pcp, s->pcp_from_free,
+ s->alloc_from_pcp * 100 / total_alloc,
+ s->pcp_from_free * 100 / total_free);
printf("RemoteObj/SlabFrozen %8lu %8lu %3lu %3lu\n",
s->deactivate_remote_frees, s->free_frozen,
@@ -1215,8 +1215,8 @@ static void read_slab_dir(void)
slab->order_fallback = get_obj("order_fallback");
slab->cmpxchg_double_cpu_fail = get_obj("cmpxchg_double_cpu_fail");
slab->cmpxchg_double_fail = get_obj("cmpxchg_double_fail");
- slab->cpu_partial_alloc = get_obj("cpu_partial_alloc");
- slab->cpu_partial_free = get_obj("cpu_partial_free");
+ slab->alloc_from_pcp = get_obj("alloc_from_pcp");
+ slab->pcp_from_free = get_obj("pcp_from_free");
slab->alloc_node_mismatch = get_obj("alloc_node_mismatch");
slab->deactivate_bypass = get_obj("deactivate_bypass");
chdir("..");
--
1.7.0.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>