Commit b2455396 authored by Paul Jackson's avatar Paul Jackson Committed by Linus Torvalds
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[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: default avatarPaul Jackson <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 151a4420
......@@ -2809,8 +2809,7 @@ static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
struct array_cache *ac;
if (unlikely(current->flags & (PF_SPREAD_PAGE | PF_SPREAD_SLAB |
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,
* 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.
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