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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v7-20020a170902b7c700b001bb9370760fsi9719455plz.90.2023.08.01.18.07.44; Tue, 01 Aug 2023 18:07:57 -0700 (PDT) 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=20221208 header.b=jrl7Ys0x; 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 S230031AbjHBAUC (ORCPT + 99 others); Tue, 1 Aug 2023 20:20:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231214AbjHBAT6 (ORCPT ); Tue, 1 Aug 2023 20:19:58 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AA6EA2113 for ; Tue, 1 Aug 2023 17:19:48 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-57320c10635so72638517b3.3 for ; Tue, 01 Aug 2023 17:19:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690935587; x=1691540387; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=DXVsJSb9QIFOr/Cp0N+IT34pRw+slorysgAR9VBW/lM=; b=jrl7Ys0xOyJWUU+1bY9AvYsLoVedsg9Qt+P5GRVgnRL82QJNvITpopMf6Y35+KiR6+ njcjAClUQ4TRB4Ew4iQEZOUMRde47mcLG3VaP/NoWN+aNNuff7bpgIyFSuKJqyCl/VaQ FNDSWcd3QRSOAYr30HQrFCbKb0BQVGZ020abfKKxfvpx7WxvVX/Cij4OvDiA073uU/1R 4MuJofEOPoOQ1o65LYZcA42/Azb4YnHyrF+DH4DjXL9KbQfuDKMm497mezw1N8ynoBCD EpKwsodi8TP5ivvB24NM8bKJWXIIaTAiPXyXwURLSlqVmPA4hdUzH630ElxNEypBuYbx EDNw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690935587; x=1691540387; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=DXVsJSb9QIFOr/Cp0N+IT34pRw+slorysgAR9VBW/lM=; b=G3vUU2IPtX6gXV+2AVgSN+M3l94zUupHClIg/wBFyEExyR8r5HuuAS48IPmxDCMsLt s7HoWp5yd2+WvvlT+1efxTMyaEjeeF4+yxflhjso/E5fbKvfKKIZsUC3cSXtFTg73cIH 9lnB7g6MMcnaL03Z0ZpjWYTrvKHMbyOCMcZTVdDDDJhrfRKCZBt5QlowSYs+RsOZpi/3 G0ovyc9obljlV4NPMqIFsud9C4MEFeNeih5kvRQ9FLL9xwVyr+iKkLSisSVTdoGYXg7Y s3rH50Yo0RZn46TC8x5KH7VvxC+U4GUJyow2S1d4TXeeNe43/7C3rft1bRzUx+7HCnA7 d02g== X-Gm-Message-State: ABy/qLZ71GOtbcco6DdziI4L6cDI04kAqSOeuBkdM2wmu/or0JsNN1Ye b7GZTfqFrdp/JSn0LznU83AY5DTqALypCk9bfA== X-Received: from kalesh.mtv.corp.google.com ([2620:15c:211:201:aa5f:ff75:318:255]) (user=kaleshsingh job=sendgmr) by 2002:a25:ab86:0:b0:d0d:a7bc:4040 with SMTP id v6-20020a25ab86000000b00d0da7bc4040mr103482ybi.0.1690935587776; Tue, 01 Aug 2023 17:19:47 -0700 (PDT) Date: Tue, 1 Aug 2023 17:19:35 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230802001938.3913174-1-kaleshsingh@google.com> Subject: [PATCH 1/3] mm-unstable: Multi-gen LRU: Fix per-zone reclaim From: Kalesh Singh To: yuzhao@google.com, akpm@linux-foundation.org Cc: surenb@google.com, android-mm@google.com, kernel-team@android.com, Kalesh Singh , Charan Teja Kalla , Lecopzer Chen , Matthias Brugger , AngeloGioacchino Del Regno , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org 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_BLOCKED,SPF_HELO_NONE,SPF_PASS,T_SCC_BODY_TEXT_LINE, 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: INBOX X-GMAIL-THRID: 1773077505451592722 X-GMAIL-MSGID: 1773077505451592722 MGLRU has a LRU list for each zone for each type (anon/file) in each generation: long nr_pages[MAX_NR_GENS][ANON_AND_FILE][MAX_NR_ZONES]; The min_seq (oldest generation) can progress independently for each type but the max_seq (youngest generation) is shared for both anon and file. This is to maintain a common frame of reference. In order for eviction to advance the min_seq of a type, all the per-zone lists in the oldest generation of that type must be empty. The eviction logic only considers pages from eligible zones for eviction or promotion. scan_folios() { ... for (zone = sc->reclaim_idx; zone >= 0; zone--) { ... sort_folio(); // Promote ... isolate_folio(); // Evict } ... } Consider the system has the movable zone configured and default 4 generations. The current state of the system is as shown below (only illustrating one type for simplicity): Type: ANON Zone DMA32 Normal Movable Device Gen 0 0 0 4GB 0 Gen 1 0 1GB 1MB 0 Gen 2 1MB 4GB 1MB 0 Gen 3 1MB 1MB 1MB 0 Now consider there is a GFP_KERNEL allocation request (eligible zone index <= Normal), evict_folios() will return without doing any work since there are no pages to scan in the eligible zones of the oldest generation. Reclaim won't make progress until triggered from a ZONE_MOVABLE allocation request; which may not happen soon if there is a lot of free memory in the movable zone. This can lead to OOM kills, although there is 1GB pages in the Normal zone of Gen 1 that we have not yet tried to reclaim. This issue is not seen in the conventional active/inactive LRU since there are no per-zone lists. If there are no (not enough) folios to scan in the eligible zones, move folios from ineligible zone (zone_index > reclaim_index) to the next generation. This allows for the progression of min_seq and reclaiming from the next generation (Gen 1). Qualcomm, Mediatek and raspberrypi [1] discovered this issue independently. [1] https://github.com/raspberrypi/linux/issues/5395 Cc: Yu Zhao Cc: Andrew Morton Reported-by: Charan Teja Kalla Reported-by: Lecopzer Chen Signed-off-by: Kalesh Singh --- mm/vmscan.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 4039620d30fe..489a4fc7d9b1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4889,7 +4889,8 @@ static int lru_gen_memcg_seg(struct lruvec *lruvec) * the eviction ******************************************************************************/ -static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx) +static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_control *sc, + int tier_idx) { bool success; int gen = folio_lru_gen(folio); @@ -4939,6 +4940,13 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, int tier_idx) return true; } + /* ineligible */ + if (zone > sc->reclaim_idx) { + gen = folio_inc_gen(lruvec, folio, false); + list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]); + return true; + } + /* waiting for writeback */ if (folio_test_locked(folio) || folio_test_writeback(folio) || (type == LRU_GEN_FILE && folio_test_dirty(folio))) { @@ -4987,7 +4995,8 @@ static bool isolate_folio(struct lruvec *lruvec, struct folio *folio, struct sca static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, int type, int tier, struct list_head *list) { - int gen, zone; + int i; + int gen; enum vm_event_item item; int sorted = 0; int scanned = 0; @@ -5003,9 +5012,10 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, gen = lru_gen_from_seq(lrugen->min_seq[type]); - for (zone = sc->reclaim_idx; zone >= 0; zone--) { + for (i = MAX_NR_ZONES; i > 0; i--) { LIST_HEAD(moved); int skipped = 0; + int zone = (sc->reclaim_idx + i) % MAX_NR_ZONES; struct list_head *head = &lrugen->folios[gen][type][zone]; while (!list_empty(head)) { @@ -5019,7 +5029,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, scanned += delta; - if (sort_folio(lruvec, folio, tier)) + if (sort_folio(lruvec, folio, sc, tier)) sorted += delta; else if (isolate_folio(lruvec, folio, sc)) { list_add(&folio->lru, list); From patchwork Wed Aug 2 00:19:36 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 129537 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:9f41:0:b0:3e4:2afc:c1 with SMTP id v1csp124265vqx; Tue, 1 Aug 2023 18:13:05 -0700 (PDT) X-Google-Smtp-Source: APBJJlHNGLDkINBa92ixrrFaFXWARAdZy3jdivrrQKgu6zYCg5GGFxkReL87XBmtjR6dOHMqi24e X-Received: by 2002:a05:6a20:a10e:b0:13d:b318:5c70 with SMTP id q14-20020a056a20a10e00b0013db3185c70mr9589383pzk.19.1690938785259; Tue, 01 Aug 2023 18:13:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690938785; cv=none; d=google.com; s=arc-20160816; b=ZlzeROGAEA1yiRawmhT3R3oaXDL7S6n+F4Yg97Bmm6jE7sLE5c+TxBK16Y9mK5peO1 qs/9JQ8CcoJf18ThWdeLGr6qUB0TK/NdAjHvGp3DYxCo2Ssuo2RvO7BfQ7Q3yo7Mjt6f +KRHDoMXnkO9AW/vdyVHRmUiTlnr6wT5XfQBouU4APQLYpMzEzJIa8mGVaki3hEUn4zh ApE5/ZUBEGKuV2OMQLei5HXm1VQBarP/qZ0NGlm+jXQfP5MU/iPvjyl8ewk3kxJ+7/rW lw/mwUvjHuM1r8NSpM3wTGlxwVznVjZUdBusr64RaCZWub26ZAO70KtKN3Nzv2gUrXHg Nk2w== 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=oILqqqD951CZa6vFO5lwCGBJV16jZziGq+aTih9CvRM=; fh=zc2UV82xgICD6dy9QxAUkQnV0/rkNP7ez3eDb9vzjmw=; b=kBVWoaUse2pR+g0ubXGQSgz/XF3a7c3PB+f8S3lg51bmuiwGzmqtLhye/tCWldsxOL XOe3yw6ozMYrdk0YNUbl8r/MDghtytObwIODtBgJ1zSJF9WTQnDgtkFxMeEAlCQqmHlQ H+/yNl83lyi2qJnPDe01JKnC7vKbASQ/T0ZVIuSwiP+mrLyR0NBIw4a/StbyQfk2z2TW JhT7UPbF4NrukE/rPgmR3dwZRbM9FA+t2YRaAtNN5ae3WQpokGYIfnaTZAJptrWHKDff T9E2KOza0JGkPBZZ43ykhB/NWE+CbI/ZAzvk2Nb/RG3FfMoFhdODnQrzJ7jnWsgOfi6D xhOw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b=liEq2TRJ; 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. 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This is because the generations are reused (the last oldest now empty generation will become the next youngest generation). inc_min_seq() is retried until successful, dropping the lru_lock and yielding the CPU on each failure, and retaking the lock before trying again: while (!inc_min_seq(lruvec, type, can_swap)) { spin_unlock_irq(&lruvec->lru_lock); cond_resched(); spin_lock_irq(&lruvec->lru_lock); } However, the initial condition that required incrementing the min_seq (nr_gens == MAX_NR_GENS) is not retested. This can change by another call to inc_max_seq() from run_aging() with force_scan=true from the debugfs interface. Since the eviction stalls when the nr_gens == MIN_NR_GENS, avoid unnecessarily incrementing the min_seq by rechecking the number of generations before each attempt. This issue was uncovered in previous discussion on the list by Yu Zhao and Aneesh Kumar [1]. [1] https://lore.kernel.org/linux-mm/CAOUHufbO7CaVm=xjEb1avDhHVvnC8pJmGyKcFf2iY_dpf+zR3w@mail.gmail.com/ Cc: Yu Zhao Cc: Aneesh Kumar K V Cc: Andrew Morton Signed-off-by: Kalesh Singh --- mm/vmscan.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 489a4fc7d9b1..6eecd291756c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4439,7 +4439,7 @@ static void inc_max_seq(struct lruvec *lruvec, bool can_swap, bool force_scan) int prev, next; int type, zone; struct lru_gen_folio *lrugen = &lruvec->lrugen; - +restart: spin_lock_irq(&lruvec->lru_lock); VM_WARN_ON_ONCE(!seq_is_valid(lruvec)); @@ -4450,11 +4450,12 @@ static void inc_max_seq(struct lruvec *lruvec, bool can_swap, bool force_scan) VM_WARN_ON_ONCE(!force_scan && (type == LRU_GEN_FILE || can_swap)); - while (!inc_min_seq(lruvec, type, can_swap)) { - spin_unlock_irq(&lruvec->lru_lock); - cond_resched(); - spin_lock_irq(&lruvec->lru_lock); - } + if (inc_min_seq(lruvec, type, can_swap)) + continue; + + spin_unlock_irq(&lruvec->lru_lock); + cond_resched(); + goto restart; } /* From patchwork Wed Aug 2 00:19:37 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kalesh Singh X-Patchwork-Id: 129544 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:9f41:0:b0:3e4:2afc:c1 with SMTP id v1csp132339vqx; Tue, 1 Aug 2023 18:31:29 -0700 (PDT) X-Google-Smtp-Source: APBJJlF0LcGbIgPZdEIlBeJWToyzwdedRGvTv7SwdtBRxwn1+0rU4RKEYnNSvJpZm1M8cC+v0y4+ X-Received: by 2002:ac2:58c8:0:b0:4fd:d6ba:73c2 with SMTP id u8-20020ac258c8000000b004fdd6ba73c2mr3274069lfo.54.1690939889575; Tue, 01 Aug 2023 18:31:29 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1690939889; cv=none; d=google.com; s=arc-20160816; b=EsWDSqWD5rUFwyq+/cDu3/OMZYY/gn+b0+6MhY1nh5asxfeMk6+w5/c/GTN3RTTlcn AyM4MZHrMDIlmi4uy9kBRTiexEDxxIUqTAD4R4DgPHazq1xS2tbhQwoecOrMz8Hz+R0q L8bz5YIKL9W0JLKhpzizAxu395n8KBvVshQPjMMyInhsG4IqW+AOrbzUTWeheeJDDA8s l3moIO4sCCpubtlWQ4bA4F55tJDHx+4YHTdgROICPle+KMHdkDyEbX+MrQGjNw8dTHtp godL7rYSCjmDkito9vwXRGecajh8i/jwVMOXlst7BTW4c0GvlZEJ120jNkIqd2f0hSOq n58g== 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=sQqMGlFvgvQ3yvXEv1c3TG8Zu+eyY93FF0SWidKY8Dg=; fh=F0WngjkdRCY/7Ywm8xfdYViEMLybP4AkpgUWgJdmerY=; b=SSR1nGGvvpWldrHIgKJ+U8s3rpO10OYu/I1RveLFWzymCLORWPCT64CssvHUWZcziJ +f4oK/fCqMJ1QmIRDEptSqr1kicRORZFiFoUxhPGBnRNkBfSMKZgEjjNMoQiRDRdMT7N c1G4uzmT4GRbvYiPZTLqnCRtdUGlO3huv7gBMRFmuBSXIl+aroKxiv1LEWs0nW8+HjAt cWDC+noVYonoo/wFzNjQbl23nHy+VxvTlrAEaWdLRgXvWAiaGm5YfOAK/IZzSRXops6S QEeOteBIop5WccE8/F+Xl+RZCf/POdE5N9rr1VCLUnc3iYXkg1M4Ud3etwsgjHglTZza bNXQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@google.com header.s=20221208 header.b="sjS9Sd/9"; 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. 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Instead deduce it from the folio type (anon/file). Cc: Yu Zhao Cc: Andrew Morton Signed-off-by: Kalesh Singh --- mm/vmscan.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 6eecd291756c..b4329f93a682 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4656,6 +4656,7 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) pte_t *pte = pvmw->pte; unsigned long addr = pvmw->address; struct folio *folio = pfn_folio(pvmw->pfn); + bool can_swap = !folio_is_file_lru(folio); struct mem_cgroup *memcg = folio_memcg(folio); struct pglist_data *pgdat = folio_pgdat(folio); struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat); @@ -4704,7 +4705,7 @@ void lru_gen_look_around(struct page_vma_mapped_walk *pvmw) if (!pte_young(ptent)) continue; - folio = get_pfn_folio(pfn, memcg, pgdat, !walk || walk->can_swap); + folio = get_pfn_folio(pfn, memcg, pgdat, can_swap); if (!folio) continue;