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 30DD5C001DF for ; Wed, 2 Aug 2023 02:56:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231616AbjHBC4d (ORCPT ); Tue, 1 Aug 2023 22:56:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231196AbjHBC4a (ORCPT ); Tue, 1 Aug 2023 22:56:30 -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 142E0273A for ; Tue, 1 Aug 2023 19:56:16 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-585f254c41aso48678347b3.1 for ; Tue, 01 Aug 2023 19:56:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1690944975; x=1691549775; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=aqehfJB+hF+Fne+AdGJurbsZIYsQCeOte57mRi2GAJw=; b=33TVVDzXg6eBl7/Vpt8F6zz+Hj/NOmdXdllc0HT3+fXbEBhkPYtEkaq37eNBBfQ//f huzyAhMvUorpNH56dDYRwA06JZVdYTEAbzfGjbqw3gBWiic0SbSYYIRLI7+dUO6KJeP/ QbLSh8xuVcrhWjh4oWX9BfGiIQ2WhcFjEVln6zdtkNbTrb8Vr/FaB0bbjGe719xWxqpC hL3EQTp/eSWIIOfcyzhoc5/BO66sBZZeI+o1Tma4ICZmtHB5eUiGscJSklwG5yeK8aOP pOTWKEoNcoXV0uOzF2WA7ODrKPaZuVgMaXvYUoulWRPVnXT17L+Vmq1QR0HZFgWxuJek tQWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690944975; x=1691549775; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=aqehfJB+hF+Fne+AdGJurbsZIYsQCeOte57mRi2GAJw=; b=ktUV9uNKEiJ4ZHirx5O0bbupTW3jow9+YcABcY/90FMTlkgKZY9VI/jMHyRmMwVQhx JBzI/JNlllloiyD3XoQqi9FIqv7d8NI8FDa+YPI3HXUQr8Z+lvByw9y1And3f9Sf9MFW PmfL/SpkJUZCB9ap+gjcJZ97w9SxqfWst7L+v5GHysQNda5SsayLKkgfjhCoJtI98g0Q CC5MHwe7YequIvkoUYlbz+rfA5+fV8GjGoyPZUibS1NXbxnrIAb0pXzJiEzivoE+wVDO ehz/U9ph4FvqWkhSrQCdliYWdkJ+eswL1bDCic3vxV9eDuSrEx6HD1vrFj3lObELUnNC KW4Q== X-Gm-Message-State: ABy/qLYm2oDy6nUaHT84s9umZVV0aG7X4rzIfoJRpccm6yDKRDK01y15 V9tm/nl8qbFF6zrfXKeCC6y7uEvQzEkJnIgK8A== X-Google-Smtp-Source: APBJJlGu4CGYprEhx9EAJQV2bkMTULOViWk9fNZltzmcAuDxS7zR2BS8SgTh3oU+2KBCXMRrlqL63XtCKu/qeEPcYg== X-Received: from kalesh.mtv.corp.google.com ([2620:15c:211:201:aa5f:ff75:318:255]) (user=kaleshsingh job=sendgmr) by 2002:a05:6902:100f:b0:cf9:3564:33cc with SMTP id w15-20020a056902100f00b00cf9356433ccmr116986ybt.13.1690944975112; Tue, 01 Aug 2023 19:56:15 -0700 (PDT) Date: Tue, 1 Aug 2023 19:56:02 -0700 Mime-Version: 1.0 X-Mailer: git-send-email 2.41.0.255.g8b1d071c50-goog Message-ID: <20230802025606.346758-1-kaleshsingh@google.com> Subject: [PATCH v2 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 , stable@vger.kernel.org, Charan Teja Kalla , Lecopzer Chen , Matthias Brugger , AngeloGioacchino Del Regno , Suleiman Souhlal , Oleksandr Natalenko , "Jan Alexander Steffens (heftig)" , Qi Zheng , Steven Barrett , Brian Geffon , Barry Song , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation") Cc: stable@vger.kernel.org Cc: Yu Zhao Cc: Andrew Morton Reported-by: Charan Teja Kalla Reported-by: Lecopzer Chen Signed-off-by: Kalesh Singh --- Changes in v2: - Add Fixes tag and cc stable 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); -- 2.41.0.255.g8b1d071c50-goog