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=ham 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 89366C43460 for ; Wed, 21 Apr 2021 07:01:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E9BF61424 for ; Wed, 21 Apr 2021 07:01:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236875AbhDUHCa (ORCPT ); Wed, 21 Apr 2021 03:02:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42920 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236264AbhDUHC0 (ORCPT ); Wed, 21 Apr 2021 03:02:26 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5433C06138B for ; Wed, 21 Apr 2021 00:01:52 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id o16so7493815plg.5 for ; Wed, 21 Apr 2021 00:01:52 -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=A5fl1hFUuv3DCtKbM5f1nutVnvGFt8a4G+iL+Kk5mXk=; b=cp0+p5CgXQjn3nK6FkTIdj6ffZFLcfA64UNFiG4+B9XxSa/L46Z8Ty47tZ5El5/VVX h4Q4furWaCjgJYFpAxrVKO1xvk/7ViBeOTY9IRV8MSSjGCKsaAsQFOjDH5IQD5jYc/BN JTUdIWgYPi71758YMJPrPD/Ugc6R5XXLxmnhkdzS/GFQ9Pr4cTFEzptduklI7LnHplis 6a4DwShMYQG/eEjE/uXqIrRM+KZIEQYZusvh6uwjLQNNu8KyubIIuR48Ead76z9Y8yFO nlGB0gaDQ99jOUajP3RwBXRRLZSqrePWGL6vU8IlN1ORjh9d0qXsJrB5pUNkurvCi9OP ZB4g== 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=A5fl1hFUuv3DCtKbM5f1nutVnvGFt8a4G+iL+Kk5mXk=; b=KwcX61tDzLeTHmJzYnuSiV1+WAhfRRO9iopVDEix7oaJSwPSfBysw8aJG04d6HLD6/ 9ctohkVcZXNOl+K59kIJvqhZCAASxSn/6m/sXdNW8Y99eAeazIWkRA53k5AiMJxneanM Mr1oRCjba9KCjU/dyoClFPWSS6UEY/ATVk5UwcjqpCLkIByY/U0bzwuHW8N8i87zrZPb qVzbPAOs5A+SN/c8i28SierQdwBPCX2MH6U+zeHsAhqfJdwMV2BvTz0g4veYXIQH3ZfD 2MwKxYyW0+CfLkvB6nDzk8jE2LopKfUv+czfnZPAKFct85vqZx1QQhJ44hUCehZW/36p TR4w== X-Gm-Message-State: AOAM533K3VjwRQDiZWfx+2t0Du2kvFL0D8H4caHJhM3s2at8aqd/Q8ig HB9xrYOAmDby9U8rwJ/LzQxC6A== X-Google-Smtp-Source: ABdhPJwjpIMC9vb5Pt4w8iw3nZk9uRy6IoD/4vdQEcqphO5TogxAIorC7KgeVY48PxyjM8VMRe3ZTg== X-Received: by 2002:a17:902:9a0a:b029:e6:bf00:8a36 with SMTP id v10-20020a1709029a0ab02900e6bf008a36mr32868861plp.51.1618988512434; Wed, 21 Apr 2021 00:01:52 -0700 (PDT) Received: from localhost.localdomain ([139.177.225.255]) by smtp.gmail.com with ESMTPSA id c4sm929842pfb.94.2021.04.21.00.01.46 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Apr 2021 00:01:52 -0700 (PDT) From: Muchun Song To: guro@fb.com, hannes@cmpxchg.org, mhocko@kernel.org, akpm@linux-foundation.org, shakeelb@google.com, vdavydov.dev@gmail.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, fam.zheng@bytedance.com, bsingharora@gmail.com, shy828301@gmail.com, alex.shi@linux.alibaba.com, Muchun Song Subject: [RFC PATCH v3 06/12] mm: thp: make deferred split queue lock safe when the LRU pages reparented Date: Wed, 21 Apr 2021 15:00:53 +0800 Message-Id: <20210421070059.69361-7-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210421070059.69361-1-songmuchun@bytedance.com> References: <20210421070059.69361-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Similar to lruvec lock, we use the same approach to make the lock safe when the LRU pages reparented. Signed-off-by: Muchun Song --- mm/huge_memory.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 05ef9e8f9af5..25025bf988f8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -497,6 +497,8 @@ static struct deferred_split *lock_split_queue(struct page *page) struct deferred_split *queue; struct mem_cgroup *memcg; + rcu_read_lock(); +retry: memcg = page_memcg(compound_head(page)); if (memcg) queue = &memcg->deferred_split_queue; @@ -504,6 +506,17 @@ static struct deferred_split *lock_split_queue(struct page *page) queue = &NODE_DATA(page_to_nid(page))->deferred_split_queue; spin_lock(&queue->split_queue_lock); + if (unlikely(memcg != page_memcg(page))) { + spin_unlock(&queue->split_queue_lock); + goto retry; + } + + /* + * Preemption is disabled in the internal of spin_lock, which can serve + * as RCU read-side critical sections. + */ + rcu_read_unlock(); + return queue; } @@ -513,6 +526,8 @@ static struct deferred_split *lock_split_queue_irqsave(struct page *page, struct deferred_split *queue; struct mem_cgroup *memcg; + rcu_read_lock(); +retry: memcg = page_memcg(compound_head(page)); if (memcg) queue = &memcg->deferred_split_queue; @@ -520,6 +535,14 @@ static struct deferred_split *lock_split_queue_irqsave(struct page *page, queue = &NODE_DATA(page_to_nid(page))->deferred_split_queue; spin_lock_irqsave(&queue->split_queue_lock, *flags); + if (unlikely(memcg != page_memcg(page))) { + spin_unlock_irqrestore(&queue->split_queue_lock, *flags); + goto retry; + } + + /* See the comments in lock_split_queue(). */ + rcu_read_unlock(); + return queue; } #else -- 2.11.0