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authorDavid Rientjes <rientjes@google.com>2013-04-29 15:06:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-29 15:54:28 -0700
commit4b59e6c4730978679b414a8da61514a2518da512 (patch)
tree241f48acea764191a458c6ae2d058b079b24f12d /mm/page_alloc.c
parentfe0bfaaff84429a35e4447d4ccd646aecf5999fb (diff)
downloadlinux-4b59e6c4730978679b414a8da61514a2518da512.tar.gz
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.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7ff1536f01b..da7a2fe7332 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.