From patchwork Fri Sep 4 23:35:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11758663 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1068213B1 for ; Fri, 4 Sep 2020 23:35:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B4AC22087C for ; Fri, 4 Sep 2020 23:35:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="pqjIXMYL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B4AC22087C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id D855C6B005A; Fri, 4 Sep 2020 19:35:29 -0400 (EDT) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id D5D636B005C; Fri, 4 Sep 2020 19:35:29 -0400 (EDT) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C737F6B005D; Fri, 4 Sep 2020 19:35:29 -0400 (EDT) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0117.hostedemail.com [216.40.44.117]) by kanga.kvack.org (Postfix) with ESMTP id B19726B005A for ; Fri, 4 Sep 2020 19:35:29 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 7A115181AC9CB for ; Fri, 4 Sep 2020 23:35:29 +0000 (UTC) X-FDA: 77226987978.07.swing27_1d15e34270b6 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 4FE011803F9B0 for ; Fri, 4 Sep 2020 23:35:29 +0000 (UTC) X-Spam-Summary: 1,0,0,20c186722f8c8386,d41d8cd98f00b204,akpm@linux-foundation.org,,RULES_HIT:41:355:379:800:960:966:967:973:988:989:1260:1263:1345:1359:1381:1431:1437:1534:1542:1711:1730:1747:1777:1792:2196:2199:2393:2525:2559:2563:2682:2685:2693:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3353:3865:3867:3870:3871:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4321:4385:5007:6261:6653:7576:7875:8660:9025:9038:9391:9545:10004:10913:11026:11473:11658:11914:12043:12048:12295:12297:12438:12517:12519:12555:12679:12783:12895:12986:13148:13230:14181:14721:14849:21080:21433:21451:21627:21819:21939:30054:30056,0,RBL:198.145.29.99:@linux-foundation.org:.lbl8.mailshell.net-64.100.201.201 62.2.0.100;04yf1x947shkhnbjwuktj5z4jqwqbyp6ciw1gsb488ha789ndyacq5yixiez6rx.tpe9kktzf8k6mea1ust9rewbrry3cqo13gkqtudyxhmqay54s46traubjpxu1qn.e-lbl8.mailshell.net-223.238.255.100,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF: fp,MSBL: X-HE-Tag: swing27_1d15e34270b6 X-Filterd-Recvd-Size: 3635 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Fri, 4 Sep 2020 23:35:28 +0000 (UTC) Received: from localhost.localdomain (c-71-198-47-131.hsd1.ca.comcast.net [71.198.47.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CCED6208FE; Fri, 4 Sep 2020 23:35:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599262528; bh=McC9JkzlgiqDtm84S0OpJILFQ702Wqlavhc8g5GZztc=; h=Date:From:To:Subject:In-Reply-To:From; b=pqjIXMYLfrZM5NKaZzZurJ38iskOUrKhJy79fjYeRysgPQ7w+LSzym6M9JyN/LQDS jFXt65OR2N88BJu0GbDvdsxfmSNVwbQySBZKHZKs3Id4si7A8ORKW7U0Oa8Lzw4o9g 3T+xfZKPNV0RycWgjRzlaEIbAsDDgxF8EisjpEIw= Date: Fri, 04 Sep 2020 16:35:27 -0700 From: Andrew Morton To: akpm@linux-foundation.org, chris@chrisdown.name, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, xlpang@linux.alibaba.com Subject: [patch 02/19] mm: memcg: fix memcg reclaim soft lockup Message-ID: <20200904233527.1lOZT1GXC%akpm@linux-foundation.org> In-Reply-To: <20200904163454.4db0e6ce0c4584d2653678a3@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: 4FE011803F9B0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Xunlei Pang Subject: mm: memcg: fix memcg reclaim soft lockup We've met softlockup with "CONFIG_PREEMPT_NONE=y", when the target memcg doesn't have any reclaimable memory. It can be easily reproduced as below: watchdog: BUG: soft lockup - CPU#0 stuck for 111s![memcg_test:2204] CPU: 0 PID: 2204 Comm: memcg_test Not tainted 5.9.0-rc2+ #12 Call Trace: shrink_lruvec+0x49f/0x640 shrink_node+0x2a6/0x6f0 do_try_to_free_pages+0xe9/0x3e0 try_to_free_mem_cgroup_pages+0xef/0x1f0 try_charge+0x2c1/0x750 mem_cgroup_charge+0xd7/0x240 __add_to_page_cache_locked+0x2fd/0x370 add_to_page_cache_lru+0x4a/0xc0 pagecache_get_page+0x10b/0x2f0 filemap_fault+0x661/0xad0 ext4_filemap_fault+0x2c/0x40 __do_fault+0x4d/0xf9 handle_mm_fault+0x1080/0x1790 It only happens on our 1-vcpu instances, because there's no chance for oom reaper to run to reclaim the to-be-killed process. Add a cond_resched() at the upper shrink_node_memcgs() to solve this issue, this will mean that we will get a scheduling point for each memcg in the reclaimed hierarchy without any dependency on the reclaimable memory in that memcg thus making it more predictable. Link: http://lkml.kernel.org/r/1598495549-67324-1-git-send-email-xlpang@linux.alibaba.com Signed-off-by: Xunlei Pang Acked-by: Chris Down Acked-by: Michal Hocko Suggested-by: Michal Hocko Acked-by: Johannes Weiner Signed-off-by: Andrew Morton --- mm/vmscan.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/mm/vmscan.c~mm-memcg-fix-memcg-reclaim-soft-lockup +++ a/mm/vmscan.c @@ -2615,6 +2615,14 @@ static void shrink_node_memcgs(pg_data_t unsigned long reclaimed; unsigned long scanned; + /* + * This loop can become CPU-bound when target memcgs + * aren't eligible for reclaim - either because they + * don't have any reclaimable pages, or because their + * memory is explicitly protected. Avoid soft lockups. + */ + cond_resched(); + mem_cgroup_calculate_protection(target_memcg, memcg); if (mem_cgroup_below_min(memcg)) {