[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 f80b523..26138c9 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2809,8 +2809,7 @@
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 @@
#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.