From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 138BDC433E3 for ; Thu, 13 Aug 2020 09:46:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B6F7B2074D for ; Thu, 13 Aug 2020 09:46:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B6F7B2074D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0EEFD6B0006; Thu, 13 Aug 2020 05:46:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0A0B46B0007; Thu, 13 Aug 2020 05:46:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ED1466B0008; Thu, 13 Aug 2020 05:46:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0127.hostedemail.com [216.40.44.127]) by kanga.kvack.org (Postfix) with ESMTP id D591A6B0006 for ; Thu, 13 Aug 2020 05:46:05 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 9C11812672 for ; Thu, 13 Aug 2020 09:46:05 +0000 (UTC) X-FDA: 77145064290.11.clam09_5903d7026ff3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin11.hostedemail.com (Postfix) with ESMTP id 6C2CB180F8B81 for ; Thu, 13 Aug 2020 09:46:05 +0000 (UTC) X-HE-Tag: clam09_5903d7026ff3 X-Filterd-Recvd-Size: 6478 Received: from out30-56.freemail.mail.aliyun.com (out30-56.freemail.mail.aliyun.com [115.124.30.56]) by imf12.hostedemail.com (Postfix) with ESMTP for ; Thu, 13 Aug 2020 09:46:02 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07425;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0U5eFTQs_1597311955; Received: from IT-FVFX43SYHV2H.local(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U5eFTQs_1597311955) by smtp.aliyun-inc.com(127.0.0.1); Thu, 13 Aug 2020 17:45:55 +0800 Subject: Re: [Resend PATCH 2/6] mm/memcg: remove useless check on page->mem_cgroup To: Michal Hocko Cc: akpm@linux-foundation.org, Johannes Weiner , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1597144232-11370-1-git-send-email-alex.shi@linux.alibaba.com> <1597144232-11370-2-git-send-email-alex.shi@linux.alibaba.com> <20200811113008.GK4793@dhcp22.suse.cz> <776b0e6f-4129-9fb9-0f66-47757cf320d5@linux.alibaba.com> <20200811135626.GL4793@dhcp22.suse.cz> <0b5e1ac3-c9c7-35e9-2661-b58430314d0a@linux.alibaba.com> <20200813062049.GA9477@dhcp22.suse.cz> From: Alex Shi Message-ID: Date: Thu, 13 Aug 2020 17:45:19 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200813062049.GA9477@dhcp22.suse.cz> Content-Type: text/plain; charset=gbk X-Rspamd-Queue-Id: 6C2CB180F8B81 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam02 Content-Transfer-Encoding: quoted-printable 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: =D4=DA 2020/8/13 =CF=C2=CE=E72:20, Michal Hocko =D0=B4=B5=C0: > On Wed 12-08-20 11:25:53, Alex Shi wrote: >> >From 999b0fe5fc65865c3b59ff28500d45572a4a9570 Mon Sep 17 00:00:00 200= 1 >> From: Alex Shi >> Date: Wed, 5 Aug 2020 21:02:30 +0800 >> Subject: [PATCH 2/6] mm/memcg: bail out early from swap accounting whe= n memcg >> is disabled >> >> If we disabled memcg by cgroup_disable=3Dmemory, page->memcg will be N= ULL >> and so the charge is skipped and that will trigger a warning like belo= w. >> Let's return from the funcs earlier. >> >> ---[ end trace f1f34bfc3b32ed2f ]--- >> anon flags:0x5005b48008000d(locked|uptodate|dirty|swapbacked) >> raw: 005005b48008000d dead000000000100 dead000000000122 ffff8897c7c76= ad1 >> raw: 0000000000000022 0000000000000000 0000000200000000 0000000000000= 000 >> page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) >=20 > Yes this is better. It would be even more informative if you added the > backtrace. The stack is a bit long. I still don't know where cause the asm_exc_page_fault? And seems the vma = is from kernel not user. >From 999b0fe5fc65865c3b59ff28500d45572a4a9570 Mon Sep 17 00:00:00 2001 From: Alex Shi Date: Wed, 5 Aug 2020 21:02:30 +0800 Subject: [PATCH 2/6] mm/memcg: bail out early from swap accounting when m= emcg is disabled If we disabled memcg by cgroup_disable=3Dmemory, page->memcg will be NULL and so the charge is skipped and that will trigger a warning like below. Let's return from the funcs earlier. anon flags:0x5005b48008000d(locked|uptodate|dirty|swapbacked) raw: 005005b48008000d dead000000000100 dead000000000122 ffff8897c7c76ad1 raw: 0000000000000022 0000000000000000 0000000200000000 0000000000000000 page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg) ... RIP: 0010:vprintk_emit+0x1f7/0x260 Code: 00 84 d2 74 72 0f b6 15 27 58 64 01 48 c7 c0 00 d4 72 82 84 d2 74 = 09 f3 90 0f b6 10 84 d2 75 f7 e8 de 0d 00 00 4c 89 e7 57 9d <0f> 1f 44 00= 00 e9 62 ff ff ff 80 3d 88 c9 3a 01 00 0f 85 54 fe ff RSP: 0018:ffffc9000faab358 EFLAGS: 00000202 RAX: ffffffff8272d400 RBX: 000000000000005e RCX: ffff88afd80d0040 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000202 RBP: ffffc9000faab3a8 R08: ffffffff8272d440 R09: 0000000000022480 R10: 00120c77be68bfac R11: 0000000000cd7568 R12: 0000000000000202 R13: 0057ffffc0080005 R14: ffffffff820a0130 R15: ffffc9000faab3e8 ? vprintk_emit+0x140/0x260 vprintk_default+0x1a/0x20 vprintk_func+0x4f/0xc4 ? vprintk_func+0x4f/0xc4 printk+0x53/0x6a ? xas_load+0xc/0x80 __dump_page.cold.6+0xff/0x4ee ? xas_init_marks+0x23/0x50 ? xas_store+0x30/0x40 ? free_swap_slot+0x43/0xd0 ? put_swap_page+0x119/0x320 ? update_load_avg+0x82/0x580 dump_page+0x9/0xb mem_cgroup_try_charge_swap+0x16e/0x1d0 get_swap_page+0x130/0x210 add_to_swap+0x41/0xc0 shrink_page_list+0x99e/0xdf0 shrink_inactive_list+0x199/0x360 shrink_lruvec+0x40d/0x650 ? _cond_resched+0x14/0x30 ? _cond_resched+0x14/0x30 shrink_node+0x226/0x6e0 do_try_to_free_pages+0xd0/0x400 try_to_free_pages+0xef/0x130 __alloc_pages_slowpath.constprop.127+0x38d/0xbd0 ? ___slab_alloc+0x31d/0x6f0 __alloc_pages_nodemask+0x27f/0x2c0 alloc_pages_vma+0x75/0x220 shmem_alloc_page+0x46/0x90 ? release_pages+0x1ae/0x410 shmem_alloc_and_acct_page+0x77/0x1c0 shmem_getpage_gfp+0x162/0x910 shmem_fault+0x74/0x210 ? filemap_map_pages+0x29c/0x410 __do_fault+0x37/0x190 handle_mm_fault+0x120a/0x1770 exc_page_fault+0x251/0x450 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 Signed-off-by: Alex Shi Reviewed-by: Roman Gushchin Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Michal Hocko Cc: Vladimir Davydov Cc: Andrew Morton Cc: cgroups@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/memcontrol.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 299382fc55a9..419cf565f40b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -7098,6 +7098,9 @@ void mem_cgroup_swapout(struct page *page, swp_entr= y_t entry) VM_BUG_ON_PAGE(PageLRU(page), page); VM_BUG_ON_PAGE(page_count(page), page); =20 + if (mem_cgroup_disabled()) + return; + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) return; =20 @@ -7163,6 +7166,9 @@ int mem_cgroup_try_charge_swap(struct page *page, s= wp_entry_t entry) struct mem_cgroup *memcg; unsigned short oldid; =20 + if (mem_cgroup_disabled()) + return 0; + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return 0; =20 --=20 1.8.3.1