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| author | Vlastimil Babka <vbabka@suse.cz> | 2017-02-24 23:56:53 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-25 02:46:54 +0100 |
| commit | 5104782011a12b04fe9cfaa6f1085bdcdedd79c4 (patch) | |
| tree | ff56727123682eda3d8dc2eb0a9b602643cebecd /mm/page_alloc.c | |
| parent | mm, page_alloc: remove redundant checks from alloc fastpath (diff) | |
| download | linux-5104782011a12b04fe9cfaa6f1085bdcdedd79c4.tar.xz linux-5104782011a12b04fe9cfaa6f1085bdcdedd79c4.zip | |
mm, page_alloc: don't check cpuset allowed twice in fast-path
Since commit 682a3385e773 ("mm, page_alloc: inline the fast path of the
zonelist iterator") we replace a NULL nodemask with
cpuset_current_mems_allowed in the fast path, so that
get_page_from_freelist() filters nodes allowed by the cpuset via
for_next_zone_zonelist_nodemask().
In that case it's pointless to additionaly check __cpuset_zone_allowed()
in each iteration, which we can avoid by not adding ALLOC_CPUSET to
alloc_flags in that scenario.
This saves some cycles in the allocator fast path on systems with one or
more non-root cpuset configured. In the slow path, ALLOC_CPUSET is
reset according to __alloc_pages_slowpath(). Without configured
cpusets, this code is disabled by a static key.
Link: http://lkml.kernel.org/r/20170124150511.5710-2-vbabka@suse.cz
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
| -rw-r--r-- | mm/page_alloc.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 65876feb86f3..46c30fa26acd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3903,9 +3903,10 @@ static inline bool prepare_alloc_pages(gfp_t gfp_mask, unsigned int order, if (cpusets_enabled()) { *alloc_mask |= __GFP_HARDWALL; - *alloc_flags |= ALLOC_CPUSET; if (!ac->nodemask) ac->nodemask = &cpuset_current_mems_allowed; + else + *alloc_flags |= ALLOC_CPUSET; } lockdep_trace_alloc(gfp_mask); |