From: Paul Jackson <pj@sgi.com>
Date: Fri, 24 Mar 2006 11:16:12 +0000 (-0800)
Subject: [PATCH] cpuset: memory_spread_slab drop useless PF_SPREAD_PAGE check
X-Git-Tag: v2.6.17-rc1~919
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b2455396be35383c4eebc6745cc718b1dd9e23df;p=linux-2.6

[PATCH] cpuset: memory_spread_slab drop useless PF_SPREAD_PAGE check

The hook in the slab cache allocation path to handle cpuset memory
spreading for tasks in cpusets with 'memory_spread_slab' enabled has a
modest performance bug.  The hook calls into the memory spreading handler
alternate_node_alloc() if either of 'memory_spread_slab' or
'memory_spread_page' is enabled, even though the handler does nothing
(albeit harmlessly) for the page case

Fix - drop PF_SPREAD_PAGE from the set of flag bits that are used to
trigger a call to alternate_node_alloc().

The page case is handled by separate hooks -- see the calls conditioned on
cpuset_do_page_mem_spread() in mm/filemap.c

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/mm/slab.c b/mm/slab.c
index f80b52388a..26138c9f8f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2809,8 +2809,7 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 	struct array_cache *ac;
 
 #ifdef CONFIG_NUMA
-	if (unlikely(current->flags & (PF_SPREAD_PAGE | PF_SPREAD_SLAB |
-							PF_MEMPOLICY))) {
+	if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
 		objp = alternate_node_alloc(cachep, flags);
 		if (objp != NULL)
 			return objp;
@@ -2849,7 +2848,7 @@ static __always_inline void *__cache_alloc(struct kmem_cache *cachep,
 
 #ifdef CONFIG_NUMA
 /*
- * Try allocating on another node if PF_SPREAD_PAGE|PF_SPREAD_SLAB|PF_MEMPOLICY.
+ * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
  *
  * If we are in_interrupt, then process context, including cpusets and
  * mempolicy, may not apply and should not be used for allocation policy.