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| author | Mel Gorman <mgorman@techsingularity.net> | 2016-05-19 17:14:01 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-05-19 19:12:14 -0700 |
| commit | 4fcb0971175f6037590d7b7772fe6619261d2165 (patch) | |
| tree | 963444f36dc778cfb4768aec404d1eb923f0982d | |
| parent | 3777999dd47ec00ec34a151b1d93c0a2b721e822 (diff) | |
| download | linux-4fcb0971175f6037590d7b7772fe6619261d2165.tar.bz2 | |
mm, page_alloc: shorten the page allocator fast path
The page allocator fast path checks page multiple times unnecessarily.
This patch avoids all the slowpath checks if the first allocation
attempt succeeds.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a3b7eb86f912..8380011d77db 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -3398,31 +3398,26 @@ retry_cpuset: ac.nodemask, &ac.preferred_zone); if (!ac.preferred_zone) { page = NULL; - goto out; + goto no_zone; } ac.classzone_idx = zonelist_zone_idx(preferred_zoneref); /* First allocation attempt */ page = get_page_from_freelist(alloc_mask, order, alloc_flags, &ac); - if (unlikely(!page)) { - /* - * Runtime PM, block IO and its error handling path - * can deadlock because I/O on the device might not - * complete. - */ - alloc_mask = memalloc_noio_flags(gfp_mask); - ac.spread_dirty_pages = false; - - page = __alloc_pages_slowpath(alloc_mask, order, &ac); - } + if (likely(page)) + goto out; - if (kmemcheck_enabled && page) - kmemcheck_pagealloc_alloc(page, order, gfp_mask); + /* + * Runtime PM, block IO and its error handling path can deadlock + * because I/O on the device might not complete. + */ + alloc_mask = memalloc_noio_flags(gfp_mask); + ac.spread_dirty_pages = false; - trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype); + page = __alloc_pages_slowpath(alloc_mask, order, &ac); -out: +no_zone: /* * When updating a task's mems_allowed, it is possible to race with * parallel threads in such a way that an allocation can fail while @@ -3434,6 +3429,12 @@ out: goto retry_cpuset; } +out: + if (kmemcheck_enabled && page) + kmemcheck_pagealloc_alloc(page, order, gfp_mask); + + trace_mm_page_alloc(page, order, alloc_mask, ac.migratetype); + return page; } EXPORT_SYMBOL(__alloc_pages_nodemask); |