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 2C6D3EEB572 for ; Sat, 9 Sep 2023 13:04:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232665AbjIINEH (ORCPT ); Sat, 9 Sep 2023 09:04:07 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52296 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232018AbjIINEH (ORCPT ); Sat, 9 Sep 2023 09:04:07 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 38E609C for ; Sat, 9 Sep 2023 06:04:03 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 50820C433C7; Sat, 9 Sep 2023 13:04:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1694264642; bh=hArHBTDzt1KASVs4qhnpUrQsPKXls1OmNwkGJn5e66U=; h=Subject:To:Cc:From:Date:From; b=dxKMH0Qq+waYfaFGBZAN6FF2JVjXI8hLacGaZlEh57DpQ277U8k+TGsVp/Fabgr4f HZpf53jywJ+xCULR9k5F+J2bDT+SI1iUojWTTma1in7O/5N3aj6+qQ4dPuL2OSSBiw xqeLTs5mjM7qnzwCYKkeXX+k7UtPRdz3v16wn5Z0= Subject: FAILED: patch "[PATCH] Multi-gen LRU: fix per-zone reclaim" failed to apply to 6.1-stable tree To: kaleshsingh@google.com, akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, angelogioacchino.delregno@collabora.com, baohua@kernel.org, bgeffon@google.com, heftig@archlinux.org, lecopzer.chen@mediatek.com, matthias.bgg@gmail.com, oleksandr@natalenko.name, quic_charante@quicinc.com, stable@vger.kernel.org, steven@liquorix.net, suleiman@google.com, surenb@google.com, yuzhao@google.com, zhengqi.arch@bytedance.com Cc: From: Date: Sat, 09 Sep 2023 14:04:00 +0100 Message-ID: <2023090959-mothproof-scarf-6195@gregkh> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 669281ee7ef731fb5204df9d948669bf32a5e68d # git commit -s git send-email --to '' --in-reply-to '2023090959-mothproof-scarf-6195@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 669281ee7ef7 ("Multi-gen LRU: fix per-zone reclaim") 6df1b2212950 ("mm: multi-gen LRU: rename lrugen->lists[] to lrugen->folios[]") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 669281ee7ef731fb5204df9d948669bf32a5e68d Mon Sep 17 00:00:00 2001 From: Kalesh Singh Date: Tue, 1 Aug 2023 19:56:02 -0700 Subject: [PATCH] Multi-gen LRU: fix per-zone reclaim 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 Link: https://lkml.kernel.org/r/20230802025606.346758-1-kaleshsingh@google.com Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation") Signed-off-by: Kalesh Singh Reported-by: Charan Teja Kalla Reported-by: Lecopzer Chen Tested-by: AngeloGioacchino Del Regno [mediatek] Tested-by: Charan Teja Kalla Cc: Yu Zhao Cc: Barry Song Cc: Brian Geffon Cc: Jan Alexander Steffens (heftig) Cc: Matthias Brugger Cc: Oleksandr Natalenko Cc: Qi Zheng Cc: Steven Barrett Cc: Suleiman Souhlal Cc: Suren Baghdasaryan Cc: Aneesh Kumar K V Cc: Signed-off-by: Andrew Morton 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);