From patchwork Tue Feb 28 08:50:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 62351 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp2902626wrd; Tue, 28 Feb 2023 01:07:30 -0800 (PST) X-Google-Smtp-Source: AK7set98vOdyq8pcx07OGpEdCH6EcnZuMHWJUVICNnBN3/chCkHlat55Jl80FOl0tNfK381LqXOi X-Received: by 2002:a17:907:60cd:b0:8eb:27de:444d with SMTP id hv13-20020a17090760cd00b008eb27de444dmr2911398ejc.0.1677575250074; Tue, 28 Feb 2023 01:07:30 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677575250; cv=none; d=google.com; s=arc-20160816; b=hwxKUrmteTuVW6r72rEDh91MA5wTrMVxRaFurNXoXmKzRlJStKat9RoHlylmvT5QmD vdENZTMZQd2sUZ+ByrC5bEpfEuiWVdf3B9WrFfHFk47OOUHELK4G3t4acwhpB8rMnV01 2gFCrQjJ3hATuT9NAXmY1olkfiKMstWBFE1CUtpQyuKHtfqYd/p5I085GIg4BiUzrrKe G4UE3hASu7AzVW6ZEbmb2LmxiyBxZirxFO/ufpQQAeb61Uggqu1Nwd8W8GVwUd5F6S6Z RfgNbIb+Hp6vUvhF4d3ZaWyXL8WBHf9mNgpFxpOtLKnBgiVRWJef29utnIMLMXak9Nhq 0lAg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=tgJC52QM6QqWzETYUfTKUV+TRKWCtnTb99Tc/z4xtcc=; b=kkkGI9HIq/BuqsXnvT7keimhXvj1p+6d65MQhn92Akq/oZbOcPkjtyGe1KsoLk80fN pkgOeDqjU/xxi1IhpJQievZ13m/eht1ihBOqIB3WBQIboDuGQ26REO6+GpQrsrPY92C0 TMZsQVVs0h4ZbOFc6hAqI8VZSioX0/v/M4WAc53KxyAYP5FsaUI7IKblPjRq2ZI2tMMt 9B3rkoHG9MZw6GzonQl+xOwlCwVtDTQfziurCTOHfrDbUh8b22eB9N5LPk4EOWm/dPTD ZEM81CrUBz3nvQ2xSJOFf4GvF6O1/RbkJ+iFq+PcDBJRJYkVxlFFPwLi8LN9rGKZ/4nU SPHA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=QpsaKClB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id f3-20020a170906824300b008e649198db8si10749082ejx.720.2023.02.28.01.07.07; Tue, 28 Feb 2023 01:07:30 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=QpsaKClB; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231151AbjB1IuX (ORCPT + 99 others); Tue, 28 Feb 2023 03:50:23 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230347AbjB1IuQ (ORCPT ); Tue, 28 Feb 2023 03:50:16 -0500 Received: from mail-pf1-x44a.google.com (mail-pf1-x44a.google.com [IPv6:2607:f8b0:4864:20::44a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63D0F3AA4 for ; Tue, 28 Feb 2023 00:50:08 -0800 (PST) Received: by mail-pf1-x44a.google.com with SMTP id l1-20020a056a0016c100b0059395f5a701so4815312pfc.13 for ; Tue, 28 Feb 2023 00:50:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1677574208; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=tgJC52QM6QqWzETYUfTKUV+TRKWCtnTb99Tc/z4xtcc=; b=QpsaKClBM6T/l157IH+7qI9Rdj6857P2of63Qy25b1ULux6HWBa7tPwczUKR822sQm Jtu4ES6VL+1NRykXmz5aiv4K55zgEU1gyffkFKfifRDKyIBnA0uJ1jjdMSq3yLorLuby A7J9nOJUGetgqw5d1Alpv1sY4oIyc7bWZD02dBipyIYqxTGJWAjh1Aoxhy0vJ4ZuLYiU ZcI+vNG4fis3fO4Q1DKAztlEJeJR69f7liSjn2WRt9qFaSe5iB8T7zMWLuiVof/9K0MV SOrTQToIej9jdyCvxdFzm7JPtyyAS6uRvP9Ms6dFChBa7ZvjPPagDLqcGbXyvNXqmUa6 KqIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677574208; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tgJC52QM6QqWzETYUfTKUV+TRKWCtnTb99Tc/z4xtcc=; b=po2ppWj24fUm4fjnlqBe9xcIYS6dzWbtJLNbaDxL9rqpiFCzpoRC72IMANND8428Gp mCI1/cHNUl1bX/veBfEou4imtb28IxRKiqgr2Uy2vIyaO+w5V2lvBCxPG7hmEJfW3WYH lbcuQ5a+o0yU1vTqh+MDWVhp45CF+cKmmgZdu4fKpUBtrRq9z2WpO20ZWZxz9j0enbhJ xWDT7sYa/6a1wDcuPTrLOQTfCOnkJjlnPPWpvO1Pib8dOj/CshvK1iT1a+sG0tccpXM8 Mjz0zbetpHYCcFFZqosL9+Wlx5VdyZ4O4bDkSyAHEjcgkJyo/lcVO42bmmYoL2JJPoJ8 s1Tg== X-Gm-Message-State: AO0yUKXYMHT+VcHCYL3MXnb905SZKhyCAiERhrWoMA0vyNjr+yAfjT0C AY4pzwNBsbADyLjH/x5M7r/8xwPLAswa47dl X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a63:b21b:0:b0:502:f4c6:3992 with SMTP id x27-20020a63b21b000000b00502f4c63992mr521403pge.4.1677574207767; Tue, 28 Feb 2023 00:50:07 -0800 (PST) Date: Tue, 28 Feb 2023 08:50:01 +0000 In-Reply-To: <20230228085002.2592473-1-yosryahmed@google.com> Mime-Version: 1.0 References: <20230228085002.2592473-1-yosryahmed@google.com> X-Mailer: git-send-email 2.39.2.722.g9855ee24e9-goog Message-ID: <20230228085002.2592473-2-yosryahmed@google.com> Subject: [PATCH v1 1/2] mm: vmscan: refactor updating reclaimed pages in reclaim_state From: Yosry Ahmed To: Alexander Viro , "Darrick J. Wong" , Christoph Lameter , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Matthew Wilcox (Oracle)" , Miaohe Lin , David Hildenbrand , Johannes Weiner , Peter Xu , NeilBrown , Shakeel Butt , Michal Hocko Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759065145343508047?= X-GMAIL-MSGID: =?utf-8?q?1759065145343508047?= During reclaim, we keep track of pages reclaimed from other means than LRU-based reclaim through scan_control->reclaim_state->reclaimed_slab, which we stash a pointer to in current task_struct. However, we keep track of more than just reclaimed slab pages through this. We also use it for clean file pages dropped through pruned inodes, and xfs buffer pages freed. Rename reclaimed_slab to reclaimed, and add a helper function that wraps updating it through current. Signed-off-by: Yosry Ahmed --- fs/inode.c | 3 +-- fs/xfs/xfs_buf.c | 3 +-- include/linux/swap.h | 5 ++++- mm/slab.c | 3 +-- mm/slob.c | 6 ++---- mm/slub.c | 5 ++--- mm/vmscan.c | 31 +++++++++++++++++++++++++------ 7 files changed, 36 insertions(+), 20 deletions(-) diff --git a/fs/inode.c b/fs/inode.c index 4558dc2f1355..1022d8ac7205 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -864,8 +864,7 @@ static enum lru_status inode_lru_isolate(struct list_head *item, __count_vm_events(KSWAPD_INODESTEAL, reap); else __count_vm_events(PGINODESTEAL, reap); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += reap; + report_freed_pages(reap); } iput(inode); spin_lock(lru_lock); diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index 54c774af6e1c..060079f1e966 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -286,8 +286,7 @@ xfs_buf_free_pages( if (bp->b_pages[i]) __free_page(bp->b_pages[i]); } - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += bp->b_page_count; + report_freed_pages(bp->b_page_count); if (bp->b_pages != bp->b_page_array) kmem_free(bp->b_pages); diff --git a/include/linux/swap.h b/include/linux/swap.h index 209a425739a9..525f0ae442f9 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -153,13 +153,16 @@ union swap_header { * memory reclaim */ struct reclaim_state { - unsigned long reclaimed_slab; + /* pages reclaimed outside of LRU-based reclaim */ + unsigned long reclaimed; #ifdef CONFIG_LRU_GEN /* per-thread mm walk data */ struct lru_gen_mm_walk *mm_walk; #endif }; +void report_freed_pages(unsigned long pages); + #ifdef __KERNEL__ struct address_space; diff --git a/mm/slab.c b/mm/slab.c index dabc2a671fc6..325634416aab 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -1392,8 +1392,7 @@ static void kmem_freepages(struct kmem_cache *cachep, struct slab *slab) smp_wmb(); __folio_clear_slab(folio); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += 1 << order; + report_freed_pages(1 << order); unaccount_slab(slab, order, cachep); __free_pages(&folio->page, order); } diff --git a/mm/slob.c b/mm/slob.c index fe567fcfa3a3..71ee00e9dd46 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -61,7 +61,7 @@ #include #include -#include /* struct reclaim_state */ +#include /* report_freed_pages() */ #include #include #include @@ -211,9 +211,7 @@ static void slob_free_pages(void *b, int order) { struct page *sp = virt_to_page(b); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += 1 << order; - + report_freed_pages(1 << order); mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE_B, -(PAGE_SIZE << order)); __free_pages(sp, order); diff --git a/mm/slub.c b/mm/slub.c index 39327e98fce3..165319bf11f1 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -11,7 +11,7 @@ */ #include -#include /* struct reclaim_state */ +#include /* report_freed_pages() */ #include #include #include @@ -2063,8 +2063,7 @@ static void __free_slab(struct kmem_cache *s, struct slab *slab) /* Make the mapping reset visible before clearing the flag */ smp_wmb(); __folio_clear_slab(folio); - if (current->reclaim_state) - current->reclaim_state->reclaimed_slab += pages; + report_freed_pages(pages); unaccount_slab(slab, order, s); __free_pages(&folio->page, order); } diff --git a/mm/vmscan.c b/mm/vmscan.c index 9c1c5e8b24b8..8846531e85a4 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -200,6 +200,29 @@ static void set_task_reclaim_state(struct task_struct *task, task->reclaim_state = rs; } +/* + * reclaim_report_freed_pages: report pages freed outside of LRU-based reclaim + * @pages: number of pages freed + * + * If the current process is undergoing a reclaim operation, + * increment the number of reclaimed pages by @pages. + */ +void report_freed_pages(unsigned long pages) +{ + if (current->reclaim_state) + current->reclaim_state->reclaimed += pages; +} +EXPORT_SYMBOL(report_freed_pages); + +static void add_non_vmscan_reclaimed(struct scan_control *sc, + struct reclaim_state *rs) +{ + if (rs) { + sc->nr_reclaimed += rs->reclaimed; + rs->reclaimed = 0; + } +} + LIST_HEAD(shrinker_list); DECLARE_RWSEM(shrinker_rwsem); @@ -5346,8 +5369,7 @@ static int shrink_one(struct lruvec *lruvec, struct scan_control *sc) vmpressure(sc->gfp_mask, memcg, false, sc->nr_scanned - scanned, sc->nr_reclaimed - reclaimed); - sc->nr_reclaimed += current->reclaim_state->reclaimed_slab; - current->reclaim_state->reclaimed_slab = 0; + add_non_vmscan_reclaimed(sc, current->reclaim_state); return success ? MEMCG_LRU_YOUNG : 0; } @@ -6472,10 +6494,7 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc) shrink_node_memcgs(pgdat, sc); - if (reclaim_state) { - sc->nr_reclaimed += reclaim_state->reclaimed_slab; - reclaim_state->reclaimed_slab = 0; - } + add_non_vmscan_reclaimed(sc, reclaim_state); /* Record the subtree's reclaim efficiency */ if (!sc->proactive) From patchwork Tue Feb 28 08:50:02 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yosry Ahmed X-Patchwork-Id: 62352 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a5d:5915:0:0:0:0:0 with SMTP id v21csp2907314wrd; Tue, 28 Feb 2023 01:19:39 -0800 (PST) X-Google-Smtp-Source: AK7set9n1+wvEwYNR/irTlg7K5tjejFAi9/m6PJJN1tECw8LnOft1fTybisy57d0rbdqFpxoGoat X-Received: by 2002:a17:902:d504:b0:19c:e842:a9e0 with SMTP id b4-20020a170902d50400b0019ce842a9e0mr2157907plg.16.1677575978822; Tue, 28 Feb 2023 01:19:38 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1677575978; cv=none; d=google.com; s=arc-20160816; b=vldkHPQqiidJFyg10AEDgro8PvxsMfFD3gJA3wWR9MsgC02eAwxU3vY4r2ozmVb95h uDNWt5MVvNIj5ltHFJUbfozrKarQXlq/tEMd0bxAaSZ4Q/HmHvcrGiKlWs+ALo5qtgbp zuoMYo7FhQNbZJ8nhb6g3puGO7e9NdV6QdnKJptYIVAeiBe71wSDoYdfEpgrweQ3QPO3 t6NRr+UR46M2PWijjiSyHTBm10N1VRhgNV4+T0+ypbDIhGR5frxbCrTFQk+mC/DXYRty Hw+z9XVLnbh2B/6QwkC1TPSe9xwKtWFtGPntOKf59awVBhBIdGIyRKf4IPLd4ztiVbey LIfQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:from:subject:message-id:references :mime-version:in-reply-to:date:dkim-signature; bh=th38ntbA4Oc2oiVVTEFN7kVCZXMfBHW5bqzoJX/NKxM=; b=ZxdtCxfVElFUnuAMZXY5W71aCLk3vIDlQuPxB0oOOqCbJAvOzOq1Sj0edFfV/VRyqy QS+/oFJhk5FnyT+XPQJNuKiGpDz7YifruqwX9le8o7j01p7mkvSZSiHPALtwHmmMYBnC LhwUjpD6c6BcvcoXXa9UZ5RpEn1LxrFy/lPbKH6nGD07YyZY8OL95m7MDzK0ubUZukGg 6TQCkw/TspMYWMvVeCvApcfd+/908muVKL/ScEijGSJAMqPThoMyNKywJGqzNGCEvELr zeM6JHkh7ddII5A7tQEkzXdkPdwXv+KHelKQsEThY3q7rWOMt4X5izOjOY78JoX3CH/v ANdA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=Qx1HMjnO; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: from out1.vger.email (out1.vger.email. [2620:137:e000::1:20]) by mx.google.com with ESMTP id jh5-20020a170903328500b0019ad3a672d8si9226386plb.83.2023.02.28.01.19.25; Tue, 28 Feb 2023 01:19:38 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20210112 header.b=Qx1HMjnO; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230315AbjB1IuZ (ORCPT + 99 others); Tue, 28 Feb 2023 03:50:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33100 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230341AbjB1IuS (ORCPT ); Tue, 28 Feb 2023 03:50:18 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87FF11A97E for ; Tue, 28 Feb 2023 00:50:10 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-536d63d17dbso199086627b3.22 for ; Tue, 28 Feb 2023 00:50:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; t=1677574209; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=th38ntbA4Oc2oiVVTEFN7kVCZXMfBHW5bqzoJX/NKxM=; b=Qx1HMjnOH9OsA3ycuQn28p/IaZ+Hp3kNuLp2QUi9h0Ycfnoty+yQNpg+WRxNuY/vYp jOY7XFohXtJylm8Zhy5PNGpA0U7IS0oAfCING0t+nz1L/hwrLlAjdn6QB4BQ7g4vN6HH OAiYlZHTTmYK4E/ibEh6T98sf4VZmgYow+qhvCLJm9G0PRCymGehRtI1hbaEgguuPSwP c7t1cNU/lIriIMXf5vdSZTLjo71hA+1rjgeHrdym+NEDcQOTi8Gy7EZ3GPG7NMQg7zho MG8uusZE7ELVwRFmlhIaXFZ9jTXMsB870R8rLfTvIx/zMtY4Y5kaKuhA8atMfdGBrjnt RIMw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677574209; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=th38ntbA4Oc2oiVVTEFN7kVCZXMfBHW5bqzoJX/NKxM=; b=ObC1h4bpj3igu82H3vkJPX3H3VJOoEngi7EozA66PoX0K+RkItC6iBgZox6AOjxhQx +LkPwoml/+ReSS5ZCcj5Gozk03UlceXBytAgJlWLaMGV02HGGcixykBQG1zffW1z5qQF eZCbozOC6D1GLSf73gZkd54AGNWCFNhJ9uRv3h6tRVph3sTWDT5625rqApaLv2RQ7L/O 5FA65bxEjwVm8vDIvak8VPavHoD4MkI5JEhid2rg27pJ3C18lLrgxC1+9eedb6S274Ax 1YmBEMdVVJ5857ihxk2Aiarm2/Prd55bTadwFgKhbSQPTv/jEUrszOe7hgWEJ2QgrMs7 3GGg== X-Gm-Message-State: AO0yUKXXHWuwOBJr+WAo3jKzry0OYDtP/t/M1aS+LUvenyj/Zw+I18Sa q5UULMdlnJ3Xy6SDIdHo56rYuEihynDIZMzN X-Received: from yosry.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:2327]) (user=yosryahmed job=sendgmr) by 2002:a81:ad67:0:b0:525:2005:7dc2 with SMTP id l39-20020a81ad67000000b0052520057dc2mr1184169ywk.1.1677574209698; Tue, 28 Feb 2023 00:50:09 -0800 (PST) Date: Tue, 28 Feb 2023 08:50:02 +0000 In-Reply-To: <20230228085002.2592473-1-yosryahmed@google.com> Mime-Version: 1.0 References: <20230228085002.2592473-1-yosryahmed@google.com> X-Mailer: git-send-email 2.39.2.722.g9855ee24e9-goog Message-ID: <20230228085002.2592473-3-yosryahmed@google.com> Subject: [PATCH v1 2/2] mm: vmscan: ignore non-LRU-based reclaim in memcg reclaim From: Yosry Ahmed To: Alexander Viro , "Darrick J. Wong" , Christoph Lameter , David Rientjes , Joonsoo Kim , Vlastimil Babka , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, "Matthew Wilcox (Oracle)" , Miaohe Lin , David Hildenbrand , Johannes Weiner , Peter Xu , NeilBrown , Shakeel Butt , Michal Hocko Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, Yosry Ahmed X-Spam-Status: No, score=-9.6 required=5.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759065909456247254?= X-GMAIL-MSGID: =?utf-8?q?1759065909456247254?= We keep track of different types of reclaimed pages through reclaim_state->reclaimed, and we add them to the reported number of reclaimed pages. For non-memcg reclaim, this makes sense. For memcg reclaim, we have no clue if those pages are charged to the memcg under reclaim. Slab pages are shared by different memcgs, so a freed slab page may have only been partially charged to the memcg under reclaim. The same goes for clean file pages from pruned inodes (on highmem systems) or xfs buffer pages, there is no way to link them to the memcg under reclaim. Stop reporting those freed pages as reclaimed pages during memcg reclaim. This should make the return value of writing to memory.reclaim, and may help reduce unnecessary reclaim retries during memcg charging. Generally, this should make the return value of try_to_free_mem_cgroup_pages() more accurate. In some limited cases (e.g. freed a slab page that was mostly charged to the memcg under reclaim), the return value of try_to_free_mem_cgroup_pages() can be underestimated, but this should be fine. The freed pages will be uncharged anyway, and we can charge the memcg the next time around as we usually do memcg reclaim in a retry loop. Signed-off-by: Yosry Ahmed --- mm/vmscan.c | 50 +++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 39 insertions(+), 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 8846531e85a4..c53659221965 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -188,6 +188,16 @@ struct scan_control { */ int vm_swappiness = 60; +static bool cgroup_reclaim(struct scan_control *sc) +{ + return sc->target_mem_cgroup; +} + +static bool global_reclaim(struct scan_control *sc) +{ + return !sc->target_mem_cgroup || mem_cgroup_is_root(sc->target_mem_cgroup); +} + static void set_task_reclaim_state(struct task_struct *task, struct reclaim_state *rs) { @@ -217,7 +227,35 @@ EXPORT_SYMBOL(report_freed_pages); static void add_non_vmscan_reclaimed(struct scan_control *sc, struct reclaim_state *rs) { - if (rs) { + /* + * Currently, reclaim_state->reclaimed includes three types of pages + * freed outside of vmscan: + * (1) Slab pages. + * (2) Clean file pages from pruned inodes. + * (3) XFS freed buffer pages. + * + * For all of these cases, we have no way of finding out whether these + * pages were related to the memcg under reclaim. For example, a freed + * slab page could have had only a single object charged to the memcg + * under reclaim. Also, populated inodes are not on shrinker LRUs + * anymore except on highmem systems. + * + * Instead of over-reporting the reclaimed pages in a memcg reclaim, + * only count such pages in system-wide reclaim. This prevents + * unnecessary retries during memcg charging and false positive from + * proactive reclaim (memory.reclaim). + * + * For uncommon cases were the freed pages were actually significantly + * charged to the memcg under reclaim, and we end up under-reporting, it + * should be fine. The freed pages will be uncharged anyway, even if + * they are not reported properly, and we will be able to make forward + * progress in charging (which is usually in a retry loop). + * + * We can go one step further, and report the uncharged objcg pages in + * memcg reclaim, to make reporting more accurate and reduce + * under-reporting, but it's probably not worth the complexity for now. + */ + if (rs && !cgroup_reclaim(sc)) { sc->nr_reclaimed += rs->reclaimed; rs->reclaimed = 0; } @@ -463,16 +501,6 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) up_read(&shrinker_rwsem); } -static bool cgroup_reclaim(struct scan_control *sc) -{ - return sc->target_mem_cgroup; -} - -static bool global_reclaim(struct scan_control *sc) -{ - return !sc->target_mem_cgroup || mem_cgroup_is_root(sc->target_mem_cgroup); -} - /** * writeback_throttling_sane - is the usual dirty throttling mechanism available? * @sc: scan_control in question