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authorDavid Rientjes <rientjes@google.com>2011-03-22 16:30:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-22 17:44:01 -0700
commit29423e77c06cee7d4e335ef4a7cbd949da978c91 (patch)
tree4020036f36a8fb93d4c1010f59caa36742ff5c25
parentddd588b5dd55f14320379961e47683db4e4c1d90 (diff)
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>
-rw-r--r--mm/page_alloc.c17
1 files changed, 16 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 36be3ba4bbed..2aaafe82f513 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1714,6 +1714,20 @@ try_next_zone:
return page;
}
+/*
+ * Large machines with many possible nodes should not always dump per-node
+ * meminfo in irq context.
+ */
+static inline bool should_suppress_show_mem(void)
+{
+ bool ret = false;
+
+#if NODES_SHIFT > 8
+ ret = in_interrupt();
+#endif
+ return ret;
+}
+
static inline int
should_alloc_retry(gfp_t gfp_mask, unsigned int order,
unsigned long pages_reclaimed)
@@ -2161,7 +2175,8 @@ nopage:
" order:%d, mode:0x%x\n",
current->comm, order, gfp_mask);
dump_stack();
- show_mem();
+ if (!should_suppress_show_mem())
+ show_mem();
}
return page;
got_pg: