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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 542D5C433ED for ; Tue, 11 May 2021 10:51:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EC3A61152 for ; Tue, 11 May 2021 10:51:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231477AbhEKKxA (ORCPT ); Tue, 11 May 2021 06:53:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55824 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231465AbhEKKw6 (ORCPT ); Tue, 11 May 2021 06:52:58 -0400 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AF822C06174A for ; Tue, 11 May 2021 03:51:52 -0700 (PDT) Received: by mail-pj1-x1031.google.com with SMTP id p17so11466711pjz.3 for ; Tue, 11 May 2021 03:51:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=XKsKB4GYgRd6f8D/mWUIDZKZ0++0gc+VH9lM9TpP6RU=; b=VVp+A4ZecBFGFSRbIs1i2QqI6JPeI905+XDW/+4NUVYBpfJKdo2mbnRAZqBaYDT4fj 4z4sAgYuQMO2Gzd88guaqjzr7QsSzWk0M6u3aSFhwuIAnhT5BWQL/0cgKQPTOI5FsaUz /gzItuJCZ+WqT7RPthjOskKDSNBtyhJ8fagVIok9ix6HJrCNF0IioVjIH4hIUBZQtzQP +jY9uc0H9L0xxB0RWb1XZatZrdQmzbCtqEVPUBVor82Q9kSw1DprU++yxJg4Ht9CyskU T1sCsNzpcnN61qhYTe6qncS6dSI8vpgLFlRmEJ5qpeRyJ1pQjYp/3sFEKP5R1+o1JB57 mjxw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=XKsKB4GYgRd6f8D/mWUIDZKZ0++0gc+VH9lM9TpP6RU=; b=qXFOwRgIXXnE1ea/9DXg65jwNoLCiZh7WZT3VxXiE8M91AmCVVYFmzkft13uZWd9Q5 k79MDHMf7d2ezGqaaShQFBWWo0ZCfL6WTSm2rbTH9KYyqmWK9eNiH8GHog7ipAB59OG8 f8fbFG/sLrZsm/4GNxFbz3lO3IjAiB+z3dD8+ddL+ZmLkz//RxHsW+cW7taOsEurksYN hFvXSOFiE6x4GEERsNN64MannDQAgB7D7N/8hXbU41yr4CnF6zQvCqCCaB+tPF974jEz h0mHsCbhYWkcAjwOXlSOkEBL7eLzJ8WmnMFsYYXhTa5v/+ZCMFlxtLMTlaap74v61yVB XZ5g== X-Gm-Message-State: AOAM53338L0mdKcFXeD+C5wbmgGEIrJ++yGE/qvcNr87G8JskEwia+y+ aFDTWzNmX8tcy95qSe780JZH1w== X-Google-Smtp-Source: ABdhPJydRosyrrbHMxbhHLsJ0w0mphTejG9nrk4d+o8QXBnZoaP/o2HTRqwJkBfCPH2wNNO8V3cQCg== X-Received: by 2002:a17:902:e8cb:b029:ee:f963:4fd8 with SMTP id v11-20020a170902e8cbb02900eef9634fd8mr28864251plg.40.1620730312287; Tue, 11 May 2021 03:51:52 -0700 (PDT) Received: from localhost.localdomain ([139.177.225.240]) by smtp.gmail.com with ESMTPSA id n18sm13501952pgj.71.2021.05.11.03.51.45 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 11 May 2021 03:51:51 -0700 (PDT) From: Muchun Song To: willy@infradead.org, akpm@linux-foundation.org, hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, shakeelb@google.com, guro@fb.com, shy828301@gmail.com, alexs@kernel.org, richard.weiyang@gmail.com, david@fromorbit.com, trond.myklebust@hammerspace.com, anna.schumaker@netapp.com Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org, zhengqi.arch@bytedance.com, duanxiongchun@bytedance.com, fam.zheng@bytedance.com, Muchun Song Subject: [PATCH 05/17] mm: list_lru: remove holding lru node lock Date: Tue, 11 May 2021 18:46:35 +0800 Message-Id: <20210511104647.604-6-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210511104647.604-1-songmuchun@bytedance.com> References: <20210511104647.604-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since commit e5bc3af7734f ("rcu: Consolidate PREEMPT and !PREEMPT synchronize_rcu()"), the critical section of spinlock can serve as RCU read-side critical section. So we can remove redundant locking from memcg_update_list_lru_node(). Signed-off-by: Muchun Song --- mm/list_lru.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 4962d48d4410..e86d4d055d3c 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -403,18 +403,9 @@ static int memcg_update_list_lru_node(struct list_lru_node *nlru, memcpy(&new->lru, &old->lru, old_size * sizeof(void *)); - /* - * The locking below allows readers that hold nlru->lock avoid taking - * rcu_read_lock (see list_lru_from_memcg_idx). - * - * Since list_lru_{add,del} may be called under an IRQ-safe lock, - * we have to use IRQ-safe primitives here to avoid deadlock. - */ - spin_lock_irq(&nlru->lock); rcu_assign_pointer(nlru->memcg_lrus, new); - spin_unlock_irq(&nlru->lock); - kvfree_rcu(old, rcu); + return 0; } -- 2.11.0