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 c78e93630d15 ("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>

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index f97b5a1..eb6c50c 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -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;
 
        /*