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| author | David Rientjes <rientjes@google.com> | 2013-04-29 15:06:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-04-29 15:54:28 -0700 |
| commit | 4b59e6c4730978679b414a8da61514a2518da512 (patch) | |
| tree | 241f48acea764191a458c6ae2d058b079b24f12d /mm/page_alloc.c | |
| parent | fe0bfaaff84429a35e4447d4ccd646aecf5999fb (diff) | |
| download | lwn-4b59e6c4730978679b414a8da61514a2518da512.tar.gz lwn-4b59e6c4730978679b414a8da61514a2518da512.zip | |
mm, show_mem: suppress page counts in non-blockable contexts
On large systems with a lot of memory, walking all RAM to determine page
types may take a half second or even more.
In non-blockable contexts, the page allocator will emit a page allocation
failure warning unless __GFP_NOWARN is specified. In such contexts, irqs
are typically disabled and such a lengthy delay may even result in NMI
watchdog timeouts.
To fix this, suppress the page walk in such contexts when printing the
page allocation failure warning.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
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 | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7ff1536f01b8..da7a2fe7332e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2003,6 +2003,13 @@ void warn_alloc_failed(gfp_t gfp_mask, int order, const char *fmt, ...) return; /* + * Walking all memory to count page types is very expensive and should + * be inhibited in non-blockable contexts. + */ + if (!(gfp_mask & __GFP_WAIT)) + filter |= SHOW_MEM_FILTER_PAGE_COUNT; + + /* * This documents exceptions given to allocations in certain * contexts that are allowed to allocate outside current's set * of allowed nodes. |