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>
diff --git a/lib/show_mem.c b/lib/show_mem.c
index 4407f8c..b7c7231 100644
--- a/lib/show_mem.c
+++ b/lib/show_mem.c
@@ -18,6 +18,9 @@
printk("Mem-Info:\n");
show_free_areas(filter);
+ if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
+ return;
+
for_each_online_pgdat(pgdat) {
unsigned long i, flags;
