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 1EEDAC433C1 for ; Tue, 30 Mar 2021 10:23:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE83E619B1 for ; Tue, 30 Mar 2021 10:23:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231855AbhC3KW5 (ORCPT ); Tue, 30 Mar 2021 06:22:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230209AbhC3KWd (ORCPT ); Tue, 30 Mar 2021 06:22:33 -0400 Received: from mail-pl1-x632.google.com (mail-pl1-x632.google.com [IPv6:2607:f8b0:4864:20::632]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AD0C7C061574 for ; Tue, 30 Mar 2021 03:22:33 -0700 (PDT) Received: by mail-pl1-x632.google.com with SMTP id t20so5916481plr.13 for ; Tue, 30 Mar 2021 03:22:33 -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=35PJPimaboX0f0GU6NT304tFzSCBj6gk52k3CNbuEN0=; b=k0pCcjq+CZH6CkeB7OZseO3R0aoXsvjx6Oxds9wSe0FcNtTLNcBYwf/eApXmFxW3DE mq4oUwM8ddJlOXfU2bjf+jON7bXFz0ciEk/omi+H0Ge+W1gyu8H7gtDPNeWxqVk4kkax 8O9fmWu+ics5JjV26PspctzHvzQZvS67iRBvMSGw7sglb7RpAryMK5ZKC2OS148Ex75J HjHhEjEKzNLCT48TIWPJBwVXsktvFsRXXJ1l0T9dia74Xt0Whr06FVLmTNvC1tmZd3y/ LyowX64eomXd4tilg5Y+Lcv7QV/EJuKgOc6XLz3G7x6byAy+ULDiudYEZYWfJrNfGetW m1VQ== 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=35PJPimaboX0f0GU6NT304tFzSCBj6gk52k3CNbuEN0=; b=YJeOIGWI6s9S1FRwNDD+jwTdtYJH5gcoqZDc6ZHnsM2mCynYDNXJ54frw+5WnnRcKh 7H6j0xXDMIEmPOuM5SVQVQahBPs4ACtUpL9hdo4d7P84jNzLDXpdx89V80pb9vxlXmZR 3TTCbyutNhEY9EggpTFFf5BlAp8/7rc11FNhTMYxVd1tME9l+dUEzuEo2EJDvfQhoUJO QMy4Ux7x7Ejmvqjx72z0Ow57pQNeNBiadij2Eh69nqrQKsOLd0/zOIyDOhyQNia5aY1j JsS1+0XN3bKKn7hRgc/DRFHvWz9hdUUi/gWqjcw6UtAAdI+Z+gPElMv00C1VuWAK7t8W X9OQ== X-Gm-Message-State: AOAM5323nx3Fwbceo5j7i1eosL5MkXkCm8nnhFUeOAhUK9hm1VRXlW48 ffiN9B6GQ4NA+T+tt7PcJz1L/Q== X-Google-Smtp-Source: ABdhPJyrZ53j9C5rLFjTDQpQ/1eARR63PEdeQ3l5NphxlX8LYCZtDeAcNu6lfko9ahvLOeA5KbhfSA== X-Received: by 2002:a17:90a:f286:: with SMTP id fs6mr3663311pjb.183.1617099753361; Tue, 30 Mar 2021 03:22:33 -0700 (PDT) Received: from localhost.localdomain ([2408:8445:ad30:68d8:c87f:ca1b:dc00:4730]) by smtp.gmail.com with ESMTPSA id k10sm202259pfk.205.2021.03.30.03.22.22 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Tue, 30 Mar 2021 03:22:33 -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, Muchun Song Subject: [RFC PATCH 10/15] mm: thp: make deferred split queue lock safe when the LRU pages reparented Date: Tue, 30 Mar 2021 18:15:26 +0800 Message-Id: <20210330101531.82752-11-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) In-Reply-To: <20210330101531.82752-1-songmuchun@bytedance.com> References: <20210330101531.82752-1-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 | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 186dc11e8992..434cc7283a64 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -496,6 +496,8 @@ 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; @@ -503,6 +505,17 @@ 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; } @@ -512,6 +525,8 @@ 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; @@ -519,6 +534,17 @@ 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; + } + + /* + * Preemption is disabled in the internal of spin_lock, which can serve + * as RCU read-side critical sections. + */ + rcu_read_unlock(); + return queue; } #else -- 2.11.0