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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 5BCD5C433ED for ; Fri, 30 Apr 2021 19:54:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CD2B613F8 for ; Fri, 30 Apr 2021 19:54:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233877AbhD3Ty5 (ORCPT ); Fri, 30 Apr 2021 15:54:57 -0400 Received: from server.lespinasse.org ([63.205.204.226]:59481 "EHLO server.lespinasse.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232414AbhD3Txg (ORCPT ); Fri, 30 Apr 2021 15:53:36 -0400 DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-14-ed; t=1619812353; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=3M8/87TWLrXUkV85tkfyDqeQTIij8rhB4JQYDhsc088=; b=IZjIOz6DZDI+XBf2HUWjGljUENDtk9JZDSEfDvngxRCnnk8zbadfNKvDaZKujidNQsLue opWTz5oBYI1wlRSCg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-14-rsa; t=1619812353; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=3M8/87TWLrXUkV85tkfyDqeQTIij8rhB4JQYDhsc088=; b=t7R2CPkdcuf0Gtgd++7LItWfcxuIgKHJzCb7pW1eIcDGF66HMlZ+vKl1dmodbHzkmn4XY uX99g0LXMoO9BY+cYVTdhCe9dOIoWjm4OGn76klITLZI9OtrTr1DJoh6yK+j7cnmDPs/vvy 6OKuko1PQapizZu+rs42+H1clr6su6rn0M5EzzUzjdUobY6IJjfrB1fAKROAhpKnpPq1bpx M2YUFn1HRw+hrmrfnCXrbuAqU8qOxZX1Aw37EwxS2pZmyFalbAe0npuqcutQrKKDWM+a6pJ PEhvvDkTl8iSpJKt6TuzvJhxnrZfVOQCo3/r4QjS7G+AjVIoAnj2vUiMTmEg== Received: from zeus.lespinasse.org (zeus.lespinasse.org [10.0.0.150]) by server.lespinasse.org (Postfix) with ESMTPS id 7F1CD16032A; Fri, 30 Apr 2021 12:52:33 -0700 (PDT) Received: by zeus.lespinasse.org (Postfix, from userid 1000) id 6F2ED19F522; Fri, 30 Apr 2021 12:52:33 -0700 (PDT) From: Michel Lespinasse To: Linux-MM , Linux-Kernel Cc: Laurent Dufour , Peter Zijlstra , Michal Hocko , Matthew Wilcox , Rik van Riel , Paul McKenney , Andrew Morton , Suren Baghdasaryan , Joel Fernandes , Andy Lutomirski , Michel Lespinasse Subject: [PATCH 17/29] mm: implement speculative handling in do_anonymous_page() Date: Fri, 30 Apr 2021 12:52:18 -0700 Message-Id: <20210430195232.30491-18-michel@lespinasse.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210430195232.30491-1-michel@lespinasse.org> References: <20210430195232.30491-1-michel@lespinasse.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 e2f9e4c096dd..d95826c48f1d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3615,8 +3615,12 @@ static vm_fault_t do_anonymous_page(struct vm_fault *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 = alloc_zeroed_user_highpage_movable(vma, vmf->address); if (!page) goto oom; @@ -3637,8 +3641,10 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) entry = pte_mkwrite(pte_mkdirty(entry)); } - vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, - &vmf->ptl); + if (!pte_map_lock(vmf)) { + ret = VM_FAULT_RETRY; + goto release; + } if (!pte_none(*vmf->pte)) { update_mmu_tlb(vma, vmf->address, vmf->pte); goto unlock; @@ -3653,6 +3659,8 @@ 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); } @@ -3670,6 +3678,7 @@ 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; -- 2.20.1