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=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 11A43C433ED for ; Wed, 7 Apr 2021 01:45:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A556B61165 for ; Wed, 7 Apr 2021 01:45:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A556B61165 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=lespinasse.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5998E6B0082; Tue, 6 Apr 2021 21:45:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0F5768E0003; Tue, 6 Apr 2021 21:45:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A465B8D0001; Tue, 6 Apr 2021 21:45:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0242.hostedemail.com [216.40.44.242]) by kanga.kvack.org (Postfix) with ESMTP id 484756B0087 for ; Tue, 6 Apr 2021 21:45:07 -0400 (EDT) Received: from smtpin34.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 090CE824999B for ; Wed, 7 Apr 2021 01:45:07 +0000 (UTC) X-FDA: 78003877854.34.3BDAC23 Received: from server.lespinasse.org (server.lespinasse.org [63.205.204.226]) by imf21.hostedemail.com (Postfix) with ESMTP id F2B68E000107 for ; Wed, 7 Apr 2021 01:45:05 +0000 (UTC) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-11-ed; t=1617759902; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=6AcV49LGNOIZDA+U0gUwsONW88L3iArajwLBo0wi7SM=; b=F/JpeEdbZWigeVCVPTTSdqZJ3RmaCAHjRMzqvo/hTl26Yo6cwAedoClDxm9iWkPyKyi+O VKNDqSGQWJJeSSUAQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-11-rsa; t=1617759902; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=6AcV49LGNOIZDA+U0gUwsONW88L3iArajwLBo0wi7SM=; b=lOJnzzUAMXbVIAnQXUc17f7ODQpWkTLCGso6d9sNX2p5sFxA+RybJ/ZRVZnHdHU7FaNJg IfHJX/dxb0wlOIz+fQZs0lG8Q9BG/eQdeBCAUqG6kQFusXFdR0h6ztBi4yUyVGGFAS2m9+K xtdu6TgWjUuI5s4nYBdpYef3SiHwztecJhR9uDtW/78irlsStfiyMLvBZvGtXNjQMxIbSDt yOGmSHGUhrGfKyAsFTWwFk5iUlb6h3VqlVEtQIshhVrGvkzY2JJSac4ItU9CtuSUucZJQBB 7A+n6k5oyhzd11dcLHzh+Q/ozbJrXboZhwyKnbNg4U+8azA7seHZbHbxF9nQ== Received: from zeus.lespinasse.org (zeus.lespinasse.org [IPv6:fd00::150:0]) by server.lespinasse.org (Postfix) with ESMTPS id AA2801602A5; Tue, 6 Apr 2021 18:45:02 -0700 (PDT) Received: by zeus.lespinasse.org (Postfix, from userid 1000) id 9A4F419F31E; Tue, 6 Apr 2021 18:45:02 -0700 (PDT) From: Michel Lespinasse To: Linux-MM Cc: Laurent Dufour , Peter Zijlstra , Michal Hocko , Matthew Wilcox , Rik van Riel , Paul McKenney , Andrew Morton , Suren Baghdasaryan , Joel Fernandes , Rom Lemarchand , Linux-Kernel , Michel Lespinasse Subject: [RFC PATCH 10/37] mm: rcu safe vma freeing Date: Tue, 6 Apr 2021 18:44:35 -0700 Message-Id: <20210407014502.24091-11-michel@lespinasse.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210407014502.24091-1-michel@lespinasse.org> References: <20210407014502.24091-1-michel@lespinasse.org> MIME-Version: 1.0 X-Stat-Signature: y4kgijnwqg7onsxid8n8rkxyysw3mbjk X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: F2B68E000107 Received-SPF: none (lespinasse.org>: No applicable sender policy available) receiver=imf21; identity=mailfrom; envelope-from=""; helo=server.lespinasse.org; client-ip=63.205.204.226 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617759905-372120 Content-Transfer-Encoding: quoted-printable 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: This prepares for speculative page faults looking up and copying vmas under protection of an rcu read lock, instead of the usual mmap read lock= . Signed-off-by: Michel Lespinasse --- include/linux/mm_types.h | 16 +++++++++++----- kernel/fork.c | 11 ++++++++++- 2 files changed, 21 insertions(+), 6 deletions(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 70882e628908..024970635921 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -304,12 +304,18 @@ struct vm_userfaultfd_ctx {}; 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, vm_end; =20 - /* linked list of VM areas per task, sorted by address */ - struct vm_area_struct *vm_next, *vm_prev; + /* linked list of VMAs per task, sorted by address */ + struct vm_area_struct *vm_next, *vm_prev; + }; +#ifdef CONFIG_SPECULATIVE_PAGE_FAULT + struct rcu_head vm_rcu; /* Used for deferred freeing. */ +#endif + }; =20 struct rb_node vm_rb; =20 diff --git a/kernel/fork.c b/kernel/fork.c index 426cd0c51f9e..b6078e546114 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -369,11 +369,20 @@ struct vm_area_struct *vm_area_dup(struct vm_area_s= truct *orig) return new; } =20 -void vm_area_free(struct vm_area_struct *vma) +#ifdef CONFIG_SPECULATIVE_PAGE_FAULT +static void __vm_area_free(struct rcu_head *head) { + struct vm_area_struct *vma =3D container_of(head, struct vm_area_struct= , + vm_rcu); kmem_cache_free(vm_area_cachep, vma); } =20 +void vm_area_free(struct vm_area_struct *vma) +{ + call_rcu(&vma->vm_rcu, __vm_area_free); +} +#endif /* CONFIG_SPECULATIVE_PAGE_FAULT */ + static void account_kernel_stack(struct task_struct *tsk, int account) { void *stack =3D task_stack_page(tsk); --=20 2.20.1