tree 4020036f36a8fb93d4c1010f59caa36742ff5c25
parent ddd588b5dd55f14320379961e47683db4e4c1d90
author David Rientjes <rientjes@google.com> 1300836647 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1300841041 -0700

oom: suppress show_mem() for many nodes in irq context on page alloc failure

When a page allocation failure occurs, show_mem() is called to dump the
state of the VM so users may understand what happened to get into that
condition.

This output, however, can be extremely verbose.  In irq context, it may
result in significant delays that incur NMI watchdog timeouts when the
machine is large (we use CONFIG_NODES_SHIFT > 8 here to define a "large"
machine since the length of the show_mem() output is proportional to the
number of possible nodes).

This patch suppresses the show_mem() call in irq context when the kernel
has CONFIG_NODES_SHIFT > 8.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>