Commit 2c029a1e authored Oct 26, 2018 by Michal Hocko Committed by Linus Torvalds Oct 26, 2018

mm, page_alloc: drop should_suppress_show_mem

should_suppress_show_mem() was introduced to reduce the overhead of
show_mem on large NUMA systems. Things have changed since then though.
Namely c78e9363 ("mm: do not walk all of system memory during
show_mem") has reduced the overhead considerably.

Moreover warn_alloc_show_mem clears SHOW_MEM_FILTER_NODES when called from
the IRQ context already so we are not printing per node stats.

Remove should_suppress_show_mem because we are losing potentially
interesting information about allocation failures. We have seen a bug
report where system gets unresponsive under memory pressure and there is
only

kernel: [2032243.696888] qlge 0000:8b:00.1 ql1: Could not get a page chunk, i=8, clean_idx =200 .
kernel: [2032243.710725] swapper/7: page allocation failure: order:1, mode:0x1084120(GFP_ATOMIC|__GFP_COLD|__GFP_COMP)

without an additional information for debugging. It would be great to see
the state of the page allocator at the moment.

Link: http://lkml.kernel.org/r/20180907114334.7088-1-mhocko@kernel.org

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent e9b257ed

mm/page_alloc.c

+1 −15

Original line number	Diff line number	Diff line
		@@ -3367,26 +3367,12 @@ try_this_zone:
		return NULL;
		}

		/*
		* 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 void warn_alloc_show_mem(gfp_t gfp_mask, nodemask_t *nodemask)
		{
		unsigned int filter = SHOW_MEM_FILTER_NODES;
		static DEFINE_RATELIMIT_STATE(show_mem_rs, HZ, 1);

		if (should_suppress_show_mem() \|\| !__ratelimit(&show_mem_rs))
		if (!__ratelimit(&show_mem_rs))
		return;

		/*

Admin message