From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-111.freemail.mail.aliyun.com (out30-111.freemail.mail.aliyun.com [115.124.30.111]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E72D748F856; Mon, 7 Sep 2026 11:01:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.111 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788778887; cv=none; b=C2TwOFm6UG5jdBYT5UsCjzaNZp4PximbXZRp2l/W4d2b5HVfXREdnPVIrpK8wgX0Z4vC/uxIfdYFbRKPCnDXMgfIDSOJgyYJScYY6Onvogdv0ogFs1xtNeQ2hpSVISPTvGGPm7RkOfawml73SVfZyQJKMaMWqy0NNQ5x8oTxD8U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788778887; c=relaxed/simple; bh=7Ftp8y+FQkkUlSbiO8cVb1oujNocCQyqrrp+m8m8p84=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=ThgCMNF197Yl3FgkJhEJEn8hTRVXAkTeP4OkJnckGPKvkl5Xqfp3hF09dQqcFsNCeFB3eZMJYr+d33HEgK4KMXQYl3FmhIiCvNxjxUZmnxReTdkhzUh+nYKdcAueaH5LqYJobkGrh9SryLycu+E0ZinTtqSGzfPIg/zzOfwfCFw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=Fo21JJN1; arc=none smtp.client-ip=115.124.30.111 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="Fo21JJN1" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1788778883; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; bh=/kTenwfhjwRZAsn2gE4kzIQoYtAxda9Qf9Jtbo1G+2k=; b=Fo21JJN17jWlrMqcmdmCYtrKIRurtFzI0FT3CbAtJ2JHEXQ6EGidRer/mbCwdbJvhkIzcZP1PfywKlao0ToevI4uTHJpWP1Y1Tyc5xiQSxU9uLGqcIQbYigYE5zcSEDaVUXx2JSYO//xbIdJ1gnXuiF4jWVud+frgqx73pVgCsI= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037026112;MF=qinyuntan@linux.alibaba.com;NM=1;PH=DS;RN=21;SR=0;TI=SMTPD_---0XATsw.a_1788778880; Received: from banye.tbsite.net(mailfrom:qinyuntan@linux.alibaba.com fp:SMTPD_---0XATsw.a_1788778880 cluster:ay36) by smtp.aliyun-inc.com; Mon, 07 Sep 2026 19:01:21 +0800 From: Qinyun Tan To: Andrew Morton Cc: Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Muchun Song , =?UTF-8?q?Michal=20Koutn=C3=BD?= , David Hildenbrand , Zi Yan , Baolin Wang , Usama Arif , Dave Chinner , Qi Zheng , Yosry Ahmed , Nhat Pham , Chengming Zhou , Xunlei Pang , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qinyun Tan Subject: [PATCH v2 4/4] mm: zswap: mark the zswap shrinker SHRINKER_NONSLAB Date: Mon, 7 Sep 2026 19:01:11 +0800 Message-ID: <20260907110111.2286932-5-qinyuntan@linux.alibaba.com> X-Mailer: git-send-email 2.43.7 In-Reply-To: <20260907110111.2286932-1-qinyuntan@linux.alibaba.com> References: <20260907110111.2286932-1-qinyuntan@linux.alibaba.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With kmem accounting disabled (cgroup.memory=nokmem), memcg reclaim never invokes the zswap shrinker: a cgroup under memory pressure does not write back its own zswapped pages to make room; they are only written back by global reclaim or once the global pool limit kicks in. The zswap shrinker is registered memcg-aware but without SHRINKER_NONSLAB, so under nokmem it is treated as a slab shrinker: before commit 03375203e1da ("mm: do not allocate shrinker info with cgroup.memory=nokmem") it was skipped by the !memcg_kmem_online() check in shrink_slab_memcg(); since that commit it is demoted to non-memcg-aware at registration. But the zswap shrinker is not a slab shrinker: it tracks zswap entries and resolves the owning memcg from the folio's objcg, independent of kmem accounting. This was noticed by Michal during review of the patch "mm/list_lru: don't copy stale shrinker id from non-memcg-aware shrinkers" [1]. Mark it SHRINKER_NONSLAB so it keeps its memcg awareness and runs under memcg reclaim with nokmem. [1] https://lore.kernel.org/lkml/697713c4-0857-485b-aba7-c74f37a3c8b4@linux.alibaba.com/ Fixes: b5ba474f3f51 ("zswap: shrink zswap pool based on memory pressure") Suggested-by: Michal Koutný Signed-off-by: Qinyun Tan Acked-by: Usama Arif --- mm/zswap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index f3ae3c81e48ea..032136942c172 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1252,8 +1252,8 @@ static struct shrinker *zswap_alloc_shrinker(void) { struct shrinker *shrinker; - shrinker = - shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE, "mm-zswap"); + shrinker = shrinker_alloc(SHRINKER_NUMA_AWARE | SHRINKER_MEMCG_AWARE | + SHRINKER_NONSLAB, "mm-zswap"); if (!shrinker) return NULL; -- 2.43.7