From patchwork Wed May 5 01:36:26 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12238883 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C864CC433B4 for ; Wed, 5 May 2021 01:36:29 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7C1F56141D for ; Wed, 5 May 2021 01:36:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7C1F56141D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 196C78D0056; Tue, 4 May 2021 21:36:29 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 16DC48D003B; Tue, 4 May 2021 21:36:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0352C8D0056; Tue, 4 May 2021 21:36:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0055.hostedemail.com [216.40.44.55]) by kanga.kvack.org (Postfix) with ESMTP id D8D938D003B for ; Tue, 4 May 2021 21:36:28 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id A7752989D for ; Wed, 5 May 2021 01:36:28 +0000 (UTC) X-FDA: 78105462456.21.D3A76F6 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf04.hostedemail.com (Postfix) with ESMTP id 4839D135 for ; Wed, 5 May 2021 01:36:23 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 34E7961413; Wed, 5 May 2021 01:36:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1620178587; bh=RH8GCwoa5L8qST8JR6UatsdfdsLj4n/wEEvkS/mnb7w=; h=Date:From:To:Subject:In-Reply-To:From; b=1CdYn8WVwyhmRUrn1Et+zAaWMgp4VGw/sF0U3jr3xaOVAeURYQJds7iXytHOH1kAf 8NFTkIASCQiC+2hTt5IuYLO4vhGWVAIvXlDoKXtKMlDnB3nKBUaD1fBlKSnugIT9qN PbrIhecv1JVkPbqV8zuhxKE5s0W9gZLPy3hoC7+w= Date: Tue, 04 May 2021 18:36:26 -0700 From: Andrew Morton To: akpm@linux-foundation.org, david@fromorbit.com, guro@fb.com, hannes@cmpxchg.org, ktkhai@virtuozzo.com, linux-mm@kvack.org, mhocko@suse.com, mm-commits@vger.kernel.org, shakeelb@google.com, shy828301@gmail.com, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 068/143] mm: vmscan: add shrinker_info_protected() helper Message-ID: <20210505013626.d8b6W0KtG%akpm@linux-foundation.org> In-Reply-To: <20210504183219.a3cc46aee4013d77402276c5@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=1CdYn8WV; dmarc=none; spf=pass (imf04.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org X-Stat-Signature: qkr8kz183wybmc3d49b9sjfjnyt8yfzf X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 4839D135 Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf04; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1620178583-599840 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Yang Shi Subject: mm: vmscan: add shrinker_info_protected() helper The shrinker_info is dereferenced in a couple of places via rcu_dereference_protected with different calling conventions, for example, using mem_cgroup_nodeinfo helper or dereferencing memcg->nodeinfo[nid]->shrinker_info. And the later patch will add more dereference places. So extract the dereference into a helper to make the code more readable. No functional change. [akpm@linux-foundation.org: retain rcu_dereference_protected() in free_shrinker_info(), per Hugh] Link: https://lkml.kernel.org/r/20210311190845.9708-8-shy828301@gmail.com Signed-off-by: Yang Shi Acked-by: Roman Gushchin Acked-by: Kirill Tkhai Acked-by: Vlastimil Babka Reviewed-by: Shakeel Butt Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Signed-off-by: Andrew Morton --- mm/vmscan.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) --- a/mm/vmscan.c~mm-vmscan-add-shrinker_info_protected-helper +++ a/mm/vmscan.c @@ -192,6 +192,13 @@ static inline int shrinker_map_size(int return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long)); } +static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg, + int nid) +{ + return rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, + lockdep_is_held(&shrinker_rwsem)); +} + static int expand_one_shrinker_info(struct mem_cgroup *memcg, int size, int old_size) { @@ -201,7 +208,7 @@ static int expand_one_shrinker_info(stru for_each_node(nid) { pn = memcg->nodeinfo[nid]; - old = rcu_dereference_protected(pn->shrinker_info, true); + old = shrinker_info_protected(memcg, nid); /* Not yet online memcg */ if (!old) return 0; @@ -675,8 +682,7 @@ static unsigned long shrink_slab_memcg(g if (!down_read_trylock(&shrinker_rwsem)) return 0; - info = rcu_dereference_protected(memcg->nodeinfo[nid]->shrinker_info, - true); + info = shrinker_info_protected(memcg, nid); if (unlikely(!info)) goto unlock;