From: Johannes Weiner <hannes@xxxxxxxxxxx> Subject: mm/page_alloc.c: ratelimit allocation failure warnings more aggressively While investigating a bug related to higher atomic allocation failures, we noticed the failure warnings positively drowning the console, and in our case trigger lockup warnings because of a serial console too slow to handle all that output. But even if we had a faster console, it's unclear what additional information the current level of repetition provides. Allocation failures happen for three reasons: The machine is OOM, the VM is failing to handle reasonable requests, or somebody is making unreasonable requests (and didn't acknowledge their opportunism with __GFP_NOWARN). Having the memory dump, a callstack, and the ratelimit stats on skipped failure warnings should provide enough information to let users/admins/developers know whether something is wrong and point them in the right direction for debugging, bpftracing etc. Limit allocation failure warnings to 1 spew every ten seconds. Link: http://lkml.kernel.org/r/20191028194906.26899-1-hannes@xxxxxxxxxxx Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 7 +------ 1 file changed, 1 insertion(+), 6 deletions(-) --- a/mm/page_alloc.c~mm-rate-limit-allocation-failure-warnings-more-aggressively +++ a/mm/page_alloc.c @@ -3728,10 +3728,6 @@ try_this_zone: 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 (!__ratelimit(&show_mem_rs)) - return; /* * This documents exceptions given to allocations in certain @@ -3752,8 +3748,7 @@ void warn_alloc(gfp_t gfp_mask, nodemask { struct va_format vaf; va_list args; - static DEFINE_RATELIMIT_STATE(nopage_rs, DEFAULT_RATELIMIT_INTERVAL, - DEFAULT_RATELIMIT_BURST); + static DEFINE_RATELIMIT_STATE(nopage_rs, 10*HZ, 1); if ((gfp_mask & __GFP_NOWARN) || !__ratelimit(&nopage_rs)) return; _
