From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f197.google.com (mail-qk0-f197.google.com [209.85.220.197]) by kanga.kvack.org (Postfix) with ESMTP id 91C646B02A4 for ; Mon, 11 Sep 2017 02:52:59 -0400 (EDT) Received: by mail-qk0-f197.google.com with SMTP id q77so11790844qke.4 for ; Sun, 10 Sep 2017 23:52:59 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id t184si8275254qkc.66.2017.09.10.23.52.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 10 Sep 2017 23:52:58 -0700 (PDT) Date: Mon, 11 Sep 2017 02:52:53 -0400 (EDT) From: Mikulas Patocka Subject: [PATCH] mm: respect the __GFP_NOWARN flag when warning about stalls Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Vlastimil Babka , Tetsuo Handa , Johannes Weiner , Mel Gorman , Dave Hansen , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org I am occasionally getting these warnings in khugepaged. It is an old machine with 550MHz CPU and 512 MB RAM. Note that khugepaged has nice value 19, so when the machine is loaded with some work, khugepaged is stalled and this stall produces warning in the allocator. khugepaged does allocations with __GFP_NOWARN, but the flag __GFP_NOWARN is masked off when calling warn_alloc. This patch removes the masking of __GFP_NOWARN, so that the warning is suppressed. khugepaged: page allocation stalls for 10273ms, order:10, mode:0x4340ca(__GFP_HIGHMEM|__GFP_IO|__GFP_FS|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_MOVABLE|__GFP_DIRECT_RECLAIM), nodemask=(null) CPU: 0 PID: 3936 Comm: khugepaged Not tainted 4.12.3 #1 Hardware name: System Manufacturer Product Name/VA-503A, BIOS 4.51 PG 08/02/00 Call Trace: ? warn_alloc+0xb9/0x140 ? __alloc_pages_nodemask+0x724/0x880 ? arch_irq_stat_cpu+0x1/0x40 ? detach_if_pending+0x80/0x80 ? khugepaged+0x10a/0x1d40 ? pick_next_task_fair+0xd2/0x180 ? wait_woken+0x60/0x60 ? kthread+0xcf/0x100 ? release_pte_page+0x40/0x40 ? kthread_create_on_node+0x40/0x40 ? ret_from_fork+0x19/0x30 Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Fixes: 63f53dea0c98 ("mm: warn about allocations which stall for too long") --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linux-2.6/mm/page_alloc.c =================================================================== --- linux-2.6.orig/mm/page_alloc.c +++ linux-2.6/mm/page_alloc.c @@ -3923,7 +3923,7 @@ retry: /* Make sure we know about allocations which stall for too long */ if (time_after(jiffies, alloc_start + stall_timeout)) { - warn_alloc(gfp_mask & ~__GFP_NOWARN, ac->nodemask, + warn_alloc(gfp_mask, ac->nodemask, "page allocation stalls for %ums, order:%u", jiffies_to_msecs(jiffies-alloc_start), order); stall_timeout += 10 * HZ; -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org