From nobody Sun Sep 14 01:46:12 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37548C54EAA for ; Fri, 27 Jan 2023 19:43:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232199AbjA0Tn2 (ORCPT ); Fri, 27 Jan 2023 14:43:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50774 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231846AbjA0TnA (ORCPT ); Fri, 27 Jan 2023 14:43:00 -0500 Received: from mail-yw1-x114a.google.com (mail-yw1-x114a.google.com [IPv6:2607:f8b0:4864:20::114a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C453F82432 for ; Fri, 27 Jan 2023 11:42:36 -0800 (PST) Received: by mail-yw1-x114a.google.com with SMTP id 00721157ae682-4ff7c6679f2so65753727b3.12 for ; Fri, 27 Jan 2023 11:42:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=Nu9/mdu38G6WtBjXb6Do7xpUyt6CdrDbmAUDhoyp47k=; b=oFyOjlhEa6jPD1d+pKzu8xqMu9sShcBJM0zkcdXAO9bWZHfs5hDegJ8sEKWFr4AQNl iGPCIH7iC8aR5RiIjRoH9W2KUncZPWl0b5vsJXQEB2UE60mYiP5ldYuNlEW3dM96CgJp +2KdvoCyVN7G6APzAMKWAfXHTUhAA+JaJZhJgfnGwlr68Zr0GLZrYj2YnOQkKo96sWGj Ng0DOWnRANnP+XQns5edhVeWyYl+9EdfDgkHbYKOkVF++Ku/0IaWanDTI7HqCQuL/w5R edw8ZGqmSQJCCmVgs5lV30HhGrOZqx2K3qMJgNbHCqjkT1CdH2dJNnKk0QEKLZZ9jCPS y7/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Nu9/mdu38G6WtBjXb6Do7xpUyt6CdrDbmAUDhoyp47k=; b=h3TEow3zRjG0lfCe5mvSQw5za2RRH4bDNJ2uFc8FE1Vk4O+/vca4y+1MhzhifpHZjF E8iCbuMu3k8njZgssRUSPH0Nd28ho8ZoHuDe/DrMao42v5gYamGAagDmFjMhhxzkzSY/ UGAvLWHmSvZ2kK07e9pNJDPSV5292hZDRv7kt29SfJpizclfJMrE8MiPfp73a38gqvcr 080uEza2rx7zqJmrUmIfF78T30hK+psCMEuX2cREmAgIXE1DQKox+FzA2kkBRXYBECRL BwOusTDNLykSbKbiuSxxKy9DNyBUFR0jTkCS2UlXO7udGjoxuP6PcHGuE+YDWaAhj8Q2 ZRHw== X-Gm-Message-State: AFqh2krEdkqLw+u/U5/61Hh8v+Wvx4W99aaUMVbiwxIw9pXjUSRW9QFK ek0PN/SUSzJ9s7kXfSjfZQEDIW8k5cQ= X-Google-Smtp-Source: AMrXdXtMMT5r56SGjlxKGvDbQirEmfUIu1ilIQcv1/3wi/4TSk/ascWeVtYTcuwkoFwuriGWfFUnQoKWHlg= X-Received: from surenb-desktop.mtv.corp.google.com ([2620:15c:211:200:4e19:be9:c5d0:8483]) (user=surenb job=sendgmr) by 2002:a0d:cdc7:0:b0:4df:f712:5d57 with SMTP id p190-20020a0dcdc7000000b004dff7125d57mr3818080ywd.303.1674848495850; Fri, 27 Jan 2023 11:41:35 -0800 (PST) Date: Fri, 27 Jan 2023 11:40:46 -0800 In-Reply-To: <20230127194110.533103-1-surenb@google.com> Mime-Version: 1.0 References: <20230127194110.533103-1-surenb@google.com> X-Mailer: git-send-email 2.39.1.456.gfc5497dd1b-goog Message-ID: <20230127194110.533103-10-surenb@google.com> Subject: [PATCH v2 09/33] mm: rcu safe VMA freeing From: Suren Baghdasaryan To: akpm@linux-foundation.org Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, rppt@kernel.org, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com, surenb@google.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Michel Lespinasse This prepares for page faults handling under VMA lock, looking up VMAs under protection of an rcu read lock, instead of the usual mmap read lock. Signed-off-by: Michel Lespinasse Signed-off-by: Suren Baghdasaryan --- include/linux/mm_types.h | 13 ++++++++++--- kernel/fork.c | 20 +++++++++++++++++++- 2 files changed, 29 insertions(+), 4 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 8410c3052148..62e413f84011 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -480,9 +480,16 @@ struct anon_vma_name { struct vm_area_struct { /* The first cache line has the info for VMA tree walking. */ =20 - unsigned long vm_start; /* Our start address within vm_mm. */ - unsigned long vm_end; /* The first byte after our end address - within vm_mm. */ + union { + struct { + /* VMA covers [vm_start; vm_end) addresses within mm */ + unsigned long vm_start; + unsigned long vm_end; + }; +#ifdef CONFIG_PER_VMA_LOCK + struct rcu_head vm_rcu; /* Used for deferred freeing. */ +#endif + }; =20 struct mm_struct *vm_mm; /* The address space we belong to. */ =20 diff --git a/kernel/fork.c b/kernel/fork.c index 5f23d5e03362..314d51eb91da 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -479,12 +479,30 @@ struct vm_area_struct *vm_area_dup(struct vm_area_str= uct *orig) return new; } =20 -void vm_area_free(struct vm_area_struct *vma) +static void __vm_area_free(struct vm_area_struct *vma) { free_anon_vma_name(vma); kmem_cache_free(vm_area_cachep, vma); } =20 +#ifdef CONFIG_PER_VMA_LOCK +static void vm_area_free_rcu_cb(struct rcu_head *head) +{ + struct vm_area_struct *vma =3D container_of(head, struct vm_area_struct, + vm_rcu); + __vm_area_free(vma); +} +#endif + +void vm_area_free(struct vm_area_struct *vma) +{ +#ifdef CONFIG_PER_VMA_LOCK + call_rcu(&vma->vm_rcu, vm_area_free_rcu_cb); +#else + __vm_area_free(vma); +#endif +} + static void account_kernel_stack(struct task_struct *tsk, int account) { if (IS_ENABLED(CONFIG_VMAP_STACK)) { --=20 2.39.1