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 7D55AEE49B3 for ; Mon, 21 Aug 2023 20:08:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230318AbjHUUIU (ORCPT ); Mon, 21 Aug 2023 16:08:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60178 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230333AbjHUUIQ (ORCPT ); Mon, 21 Aug 2023 16:08:16 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D6CCF131; Mon, 21 Aug 2023 13:08:14 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 7359F649EE; Mon, 21 Aug 2023 20:08:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C303CC433CB; Mon, 21 Aug 2023 20:08:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1692648493; bh=3i20pnBEinCK9ddZDRR6NoRQ8BsgF+99CG156P4J0Yg=; h=Date:To:From:Subject:From; b=CJVdbs0ZqLumnX4QeWRxevcj5kNOBso45ka78tEyBcGqOJZngoc5ocH2921CeWewG 7ZxdHaZV28H+l5tkTz0ocB9DHw7tiwYkYKHXnLno6WUZuOFYGLuve6Bac4VbBdsxkU AjQ19h65VjTAgkhjeN1B3jBFJqxxLk5oQq/q7CBk= Date: Mon, 21 Aug 2023 13:08:13 -0700 To: mm-commits@vger.kernel.org, yuzhao@google.com, stable@vger.kernel.org, tjmercier@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-multi-gen-lru-dont-spin-during-memcg-release.patch removed from -mm tree Message-Id: <20230821200813.C303CC433CB@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The quilt patch titled Subject: mm: multi-gen LRU: don't spin during memcg release has been removed from the -mm tree. Its filename was mm-multi-gen-lru-dont-spin-during-memcg-release.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: "T.J. Mercier" Subject: mm: multi-gen LRU: don't spin during memcg release Date: Mon, 14 Aug 2023 15:16:36 +0000 When a memcg is in the process of being released mem_cgroup_tryget will fail because its reference count has already reached 0. This can happen during reclaim if the memcg has already been offlined, and we reclaim all remaining pages attributed to the offlined memcg. shrink_many attempts to skip the empty memcg in this case, and continue reclaiming from the remaining memcgs in the old generation. If there is only one memcg remaining, or if all remaining memcgs are in the process of being released then shrink_many will spin until all memcgs have finished being released. The release occurs through a workqueue, so it can take a while before kswapd is able to make any further progress. This fix results in reductions in kswapd activity and direct reclaim in a test where 28 apps (working set size > total memory) are repeatedly launched in a random sequence: A B delta ratio(%) allocstall_movable 5962 3539 -2423 -40.64 allocstall_normal 2661 2417 -244 -9.17 kswapd_high_wmark_hit_quickly 53152 7594 -45558 -85.71 pageoutrun 57365 11750 -45615 -79.52 Link: https://lkml.kernel.org/r/20230814151636.1639123-1-tjmercier@google.com Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists") Signed-off-by: T.J. Mercier Acked-by: Yu Zhao Cc: Signed-off-by: Andrew Morton --- mm/vmscan.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) --- a/mm/vmscan.c~mm-multi-gen-lru-dont-spin-during-memcg-release +++ a/mm/vmscan.c @@ -4854,16 +4854,17 @@ void lru_gen_release_memcg(struct mem_cg spin_lock_irq(&pgdat->memcg_lru.lock); - VM_WARN_ON_ONCE(hlist_nulls_unhashed(&lruvec->lrugen.list)); + if (hlist_nulls_unhashed(&lruvec->lrugen.list)) + goto unlock; gen = lruvec->lrugen.gen; - hlist_nulls_del_rcu(&lruvec->lrugen.list); + hlist_nulls_del_init_rcu(&lruvec->lrugen.list); pgdat->memcg_lru.nr_memcgs[gen]--; if (!pgdat->memcg_lru.nr_memcgs[gen] && gen == get_memcg_gen(pgdat->memcg_lru.seq)) WRITE_ONCE(pgdat->memcg_lru.seq, pgdat->memcg_lru.seq + 1); - +unlock: spin_unlock_irq(&pgdat->memcg_lru.lock); } } @@ -5435,8 +5436,10 @@ restart: rcu_read_lock(); hlist_nulls_for_each_entry_rcu(lrugen, pos, &pgdat->memcg_lru.fifo[gen][bin], list) { - if (op) + if (op) { lru_gen_rotate_memcg(lruvec, op); + op = 0; + } mem_cgroup_put(memcg); @@ -5444,7 +5447,7 @@ restart: memcg = lruvec_memcg(lruvec); if (!mem_cgroup_tryget(memcg)) { - op = 0; + lru_gen_release_memcg(memcg); memcg = NULL; continue; } _ Patches currently in -mm which might be from tjmercier@google.com are