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 BDC57C433F5 for ; Sat, 29 Jan 2022 03:35:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352310AbiA2Dfh (ORCPT ); Fri, 28 Jan 2022 22:35:37 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:52878 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241053AbiA2Dff (ORCPT ); Fri, 28 Jan 2022 22:35:35 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1643427334; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=hQBH9GHjqS+rcFX3pcvUpks72KYFeedJ6djvUFY0Gn8=; b=O7dSL0+11b9DTlW18CTRntnV/jiLt1yGGixh/y7pMWhIyUJpvZ2Y9IwtMM9/plTA2XN6If cRi3iKONbWyGXlomtfCNaW9hy9xTOFhP/theZ1Hg7D75c9KBPdh4avG9YMlG8mlwVpRqE/ BAJvuH34o0HYkMCniQx4p/KV8+KyETk= 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-594-z98i_43JPHSrFhuU4R2vnw-1; Fri, 28 Jan 2022 22:35:31 -0500 X-MC-Unique: z98i_43JPHSrFhuU4R2vnw-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 A06EF1006AA5; Sat, 29 Jan 2022 03:35:29 +0000 (UTC) Received: from [10.22.32.53] (unknown [10.22.32.53]) by smtp.corp.redhat.com (Postfix) with ESMTP id 357EE60BD8; Sat, 29 Jan 2022 03:35:22 +0000 (UTC) Message-ID: <1badb3ac-6631-68ac-364d-69dee237583c@redhat.com> Date: Fri, 28 Jan 2022 22:35:22 -0500 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.4.0 Subject: Re: [PATCH 2/2] mm/page_owner: Dump memcg information Content-Language: en-US To: Ira Weiny Cc: Johannes Weiner , Michal Hocko , Vladimir Davydov , Andrew Morton , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, Rafael Aquini References: <20220128195642.416743-1-longman@redhat.com> <20220128195642.416743-3-longman@redhat.com> <20220128212249.GI785175@iweiny-DESK2.sc.intel.com> <20220128214843.GJ785175@iweiny-DESK2.sc.intel.com> From: Waiman Long In-Reply-To: <20220128214843.GJ785175@iweiny-DESK2.sc.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/28/22 16:48, Ira Weiny wrote: > On Fri, Jan 28, 2022 at 04:31:07PM -0500, Waiman Long wrote: >> On 1/28/22 16:22, Ira Weiny wrote: >>> On Fri, Jan 28, 2022 at 02:56:42PM -0500, Waiman Long wrote: >>>> It was found that a number of offlined memcgs were not freed because >>>> they were pinned by some charged pages that were present. Even "echo >>>> 1 > /proc/sys/vm/drop_caches" wasn't able to free those pages. These >>>> offlined but not freed memcgs tend to increase in number over time with >>>> the side effect that percpu memory consumption as shown in /proc/meminfo >>>> also increases over time. >>>> >>>> In order to find out more information about those pages that pin >>>> offlined memcgs, the page_owner feature is extended to dump memory >>>> cgroup information especially whether the cgroup is offlined or not. >>>> >>>> Signed-off-by: Waiman Long >>>> --- >>>> mm/page_owner.c | 28 ++++++++++++++++++++++++++++ >>>> 1 file changed, 28 insertions(+) >>>> >>>> diff --git a/mm/page_owner.c b/mm/page_owner.c >>>> index c52ce9d6bc3b..e5d8c642296b 100644 >>>> --- a/mm/page_owner.c >>>> +++ b/mm/page_owner.c >>>> @@ -10,6 +10,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> #include >>>> #include "internal.h" >>>> @@ -339,6 +340,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, >>>> depot_stack_handle_t handle) >>>> { >>>> int ret = 0, pageblock_mt, page_mt; >>>> + unsigned long __maybe_unused memcg_data; >>>> char *kbuf; >>>> count = min_t(size_t, count, PAGE_SIZE); >>>> @@ -371,6 +373,32 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, >>>> "Page has been migrated, last migrate reason: %s\n", >>>> migrate_reason_names[page_owner->last_migrate_reason]); >>>> +#ifdef CONFIG_MEMCG >>>> + /* >>>> + * Look for memcg information and print it out >>>> + */ >>>> + memcg_data = READ_ONCE(page->memcg_data); >>>> + if (memcg_data) { >>>> + struct mem_cgroup *memcg = page_memcg_check(page); >>>> + bool onlined; >>>> + char name[80]; >>>> + >>>> + if (memcg_data & MEMCG_DATA_OBJCGS) >>>> + SNPRINTF(kbuf, count, ret, err, "Slab cache page\n"); >>>> + >>>> + if (!memcg) >>>> + goto copy_out; >>>> + >>>> + onlined = (memcg->css.flags & CSS_ONLINE); >>>> + cgroup_name(memcg->css.cgroup, name, sizeof(name) - 1); >>>> + SNPRINTF(kbuf, count, ret, err, "Charged %sto %smemcg %s\n", >>> ^^^ >>> Extra specifier? >>> >>> Did this compile without warnings? >> Yes, there was no warning. > But isn't that an extra specifier? There are 3 arguments to the format string that match the 3 "%s" in it: 1) PageMemcgKmem(page) ? "(via objcg) " : "" 2) onlined ? "" : "offlined 3) name Cheers, Longman