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 DE84DC433ED for ; Wed, 7 Apr 2021 01:45:36 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 89A51613A7 for ; Wed, 7 Apr 2021 01:45:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 89A51613A7 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 C75DB8E0002; Tue, 6 Apr 2021 21:45:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 64FFA6B0098; Tue, 6 Apr 2021 21:45:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D08668D000D; Tue, 6 Apr 2021 21:45:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0026.hostedemail.com [216.40.44.26]) by kanga.kvack.org (Postfix) with ESMTP id 3D0506B0083 for ; Tue, 6 Apr 2021 21:45:08 -0400 (EDT) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 075B562E8 for ; Wed, 7 Apr 2021 01:45:08 +0000 (UTC) X-FDA: 78003877896.11.618B51B Received: from server.lespinasse.org (server.lespinasse.org [63.205.204.226]) by imf01.hostedemail.com (Postfix) with ESMTP id 155AD5001528 for ; Wed, 7 Apr 2021 01:45:06 +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=Iko8U1DIjbSXvB60SArqfpM0eO/JE4XY/9ww0rF5/tY=; b=JVh6JjMxzNn89HcbkhtljBCgR0nVPb//5K8shZAbIxj2Lntf8NNBDz3YEx3UFhO1kxgKJ 5YqE9FEx0+LD369DQ== 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=Iko8U1DIjbSXvB60SArqfpM0eO/JE4XY/9ww0rF5/tY=; b=dQPZHYw1jXJV689ACtM7eUIebt/kBXCd1dvdwBsYusq7L0GLbnqv2wFVikzZALG4eQHo0 hoYZ698ZhW9JVnYeTvVtYzKqNbyqh3sPMi8zirwDBwYhqXnd3a1YM2zYR+HuhFYu7FhwnJk VxWIMqJfqNWERV00aB2/UL2n2xZ2W6Rk2nQIPywaAzkmH+w2K6j4UepxDlR4xyiX9KSqoF0 lAwEqlEnrdlUjWpgBD+rlPCDDg75oOc+D9ZigT09EvxvepHfigE3X9S5ubzIc+GPWGt8qAy nyTOnIaOpDbdhTh2qphkLIKriI8niYvWYpvqDBXm8jrwEDynAzF4+3+P9+LQ== Received: from zeus.lespinasse.org (zeus.lespinasse.org [10.0.0.150]) by server.lespinasse.org (Postfix) with ESMTPS id CE9BA1602D7; Tue, 6 Apr 2021 18:45:02 -0700 (PDT) Received: by zeus.lespinasse.org (Postfix, from userid 1000) id BE65319F31F; 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 15/37] mm: implement speculative handling in do_anonymous_page() Date: Tue, 6 Apr 2021 18:44:40 -0700 Message-Id: <20210407014502.24091-16-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-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 155AD5001528 X-Stat-Signature: cpdq5aa4ykf7apsc5f6pa3ryq9rj15xd Received-SPF: none (lespinasse.org>: No applicable sender policy available) receiver=imf01; identity=mailfrom; envelope-from=""; helo=server.lespinasse.org; client-ip=63.205.204.226 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1617759906-795460 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: Change do_anonymous_page() to handle the speculative case. This involves aborting speculative faults if they have to allocate a new anon_vma, and using pte_map_lock() instead of pte_offset_map_lock() to complete the page fault. Signed-off-by: Michel Lespinasse --- mm/memory.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index 3e192d5f89a6..fd84576f9c01 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3598,8 +3598,12 @@ static vm_fault_t do_anonymous_page(struct vm_faul= t *vmf) vma->vm_page_prot)); } else { /* Allocate our own private page. */ - if (unlikely(anon_vma_prepare(vma))) - goto oom; + if (unlikely(!vma->anon_vma)) { + if (vmf->flags & FAULT_FLAG_SPECULATIVE) + return VM_FAULT_RETRY; + if (__anon_vma_prepare(vma)) + goto oom; + } page =3D alloc_zeroed_user_highpage_movable(vma, vmf->address); if (!page) goto oom; @@ -3620,8 +3624,10 @@ static vm_fault_t do_anonymous_page(struct vm_faul= t *vmf) entry =3D pte_mkwrite(pte_mkdirty(entry)); } =20 - vmf->pte =3D pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, - &vmf->ptl); + if (!pte_map_lock(vmf)) { + ret =3D VM_FAULT_RETRY; + goto release; + } if (!pte_none(*vmf->pte)) { update_mmu_tlb(vma, vmf->address, vmf->pte); goto unlock; @@ -3636,6 +3642,8 @@ static vm_fault_t do_anonymous_page(struct vm_fault= *vmf) pte_unmap_unlock(vmf->pte, vmf->ptl); if (page) put_page(page); + if (vmf->flags & FAULT_FLAG_SPECULATIVE) + return VM_FAULT_RETRY; return handle_userfault(vmf, VM_UFFD_MISSING); } =20 @@ -3653,6 +3661,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault= *vmf) return 0; unlock: pte_unmap_unlock(vmf->pte, vmf->ptl); +release: if (page) put_page(page); return ret; --=20 2.20.1