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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 228FFC433FE for ; Fri, 28 Jan 2022 19:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351008AbiA1T5e (ORCPT ); Fri, 28 Jan 2022 14:57:34 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:53114 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351004AbiA1T52 (ORCPT ); Fri, 28 Jan 2022 14:57:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643399848; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=4AGco3DPR26g1wodgd1tvssEUzEAzvT6zrwEdwptTuI=; b=O2RyyyQTcsLDCoHy8P5gN8RCTM1P4YNXAecVG4YyurJgpeF3ccBj+M1Lp9QxbYrIyI5j3y ufRV1HV1qtI2WYNTrQI3wIXB8GodNA8Jwo8+XXNqTcFyB4UNabUVOi8uFbE6KBZYkYZzNa 3m7mWRsPexD8D18VIAapfM+oqB9cyXc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-446-fDMU9u6qPrK01Ep4O1Qnuw-1; Fri, 28 Jan 2022 14:57:24 -0500 X-MC-Unique: fDMU9u6qPrK01Ep4O1Qnuw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 818EF1083F64; Fri, 28 Jan 2022 19:57:23 +0000 (UTC) Received: from llong.com (unknown [10.22.33.1]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8D5925DB82; Fri, 28 Jan 2022 19:57:10 +0000 (UTC) From: Waiman Long To: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Rafael Aquini , Waiman Long Subject: [PATCH 0/2] mm/page_owner: Extend page_owner to show memcg Date: Fri, 28 Jan 2022 14:56:40 -0500 Message-Id: <20220128195642.416743-1-longman@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While debugging the constant increase in percpu memory consumption on a system that spawned large number of containers, it was found that a lot of offlined mem_cgroup structures remained in place without being freed. Further investigation indicated that those mem_cgroup structures were pinned by some pages. In order to find out what those pages are, the existing page_owner debugging tool is extended to show memory cgroup information and whether those memcgs are offlined or not. With the enhanced page_owner tool, the following is a typical page that pinned the mem_cgroup structure in my test case: Page allocated via order 0, mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 62760, ts 119274296592 ns, free_ts 118989764823 ns PFN 1273412 type Movable Block 2487 type Movable Flags 0x17ffffc00c001c(uptodate|dirty|lru|reclaim|swapbacked|node=0|zone=2|lastcpupid=0x1fffff) prep_new_page+0x8e/0xb0 get_page_from_freelist+0xc4d/0xe50 __alloc_pages+0x172/0x320 alloc_pages_vma+0x84/0x230 shmem_alloc_page+0x3f/0x90 shmem_alloc_and_acct_page+0x76/0x1c0 shmem_getpage_gfp+0x48d/0x890 shmem_write_begin+0x36/0xc0 generic_perform_write+0xed/0x1d0 __generic_file_write_iter+0xdc/0x1b0 generic_file_write_iter+0x5d/0xb0 new_sync_write+0x11f/0x1b0 vfs_write+0x1ba/0x2a0 ksys_write+0x59/0xd0 do_syscall_64+0x37/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Charged to offlined memcg libpod-conmon-e59cc83faf807bacc61223fec6a80c1540ebe8f83c802870c6af4708d58f77ea So the page was not freed because it was part of a shmem segment. That is useful information that can help users to diagnose similar problems. Waiman Long (2): mm/page_owner: Introduce SNPRINTF() macro that includes length error check mm/page_owner: Dump memcg information mm/page_owner.c | 76 ++++++++++++++++++++++++++++++++----------------- 1 file changed, 50 insertions(+), 26 deletions(-) -- 2.27.0