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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11D8FC433EF for ; Fri, 28 Jan 2022 13:20:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348517AbiA1NUR (ORCPT ); Fri, 28 Jan 2022 08:20:17 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348693AbiA1NTK (ORCPT ); Fri, 28 Jan 2022 08:19:10 -0500 Received: from server.lespinasse.org (server.lespinasse.org [IPv6:2001:470:82ab::100:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7B5E5C061751 for ; Fri, 28 Jan 2022 05:19:08 -0800 (PST) DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-52-ed; t=1643375407; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=s8IABzRzP3ySJUm3FAWGVRKOhNvfxqtE36yoL1LaJ64=; b=5YyiNFsYpzIQby2cs2RNO6bfzcHVJCc1OHBveg/UD65LrGPfoSpZ46OpZtGa2uzUYJVj/ 0CwrThBTUJzA/lPCg== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lespinasse.org; i=@lespinasse.org; q=dns/txt; s=srv-52-rsa; t=1643375407; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : from; bh=s8IABzRzP3ySJUm3FAWGVRKOhNvfxqtE36yoL1LaJ64=; b=RF2Qg4JiQv/B2GTmiJJJgrrzl0zjMUIsaOF/jROil5LtN55Hp11eOn04jBQmSOL/orKqR NcRlQHquDKLgJDhikMo0h99LT9sdFuGHryzYZBQV3gj29cL4fKU1FoleONoLfphsNbzACNp +k8D1ucVhjB6SzuVMWlasEAGRwzN5/c7KWRSEbagrLzMxcnrW4utpUEfsgs/27LchjqNmCH uQx9u9MHz2A/KB0Zi5EcmkAJJpctcV8quh6MV402l66mgoAP+hsmfuQihBBbN4MbgSGT2tN IyWX9f8J7LN5Lfo5PIc24TCTKikYUogJPRb0nG7pdVGXMUoZwg/WyIS7ZBbQ== Received: from zeus.lespinasse.org (zeus.lespinasse.org [IPv6:fd00::150:0]) by server.lespinasse.org (Postfix) with ESMTPS id 1D48E160AA0; Fri, 28 Jan 2022 05:10:07 -0800 (PST) Received: by zeus.lespinasse.org (Postfix, from userid 1000) id 00D4520557; Fri, 28 Jan 2022 05:10:07 -0800 (PST) From: Michel Lespinasse To: Linux-MM , linux-kernel@vger.kernel.org, Andrew Morton Cc: kernel-team@fb.com, Laurent Dufour , Jerome Glisse , Peter Zijlstra , Michal Hocko , Vlastimil Babka , Davidlohr Bueso , Matthew Wilcox , Liam Howlett , Rik van Riel , Paul McKenney , Song Liu , Suren Baghdasaryan , Minchan Kim , Joel Fernandes , David Rientjes , Axel Rasmussen , Andy Lutomirski , Michel Lespinasse Subject: [PATCH v2 19/35] mm: enable speculative fault handling through do_anonymous_page() Date: Fri, 28 Jan 2022 05:09:50 -0800 Message-Id: <20220128131006.67712-20-michel@lespinasse.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20220128131006.67712-1-michel@lespinasse.org> References: <20220128131006.67712-1-michel@lespinasse.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org in x86 fault handler, only attempt spf if the vma is anonymous. In do_handle_mm_fault(), let speculative page faults proceed as long as they fall into anonymous vmas. This enables the speculative handling code in __handle_mm_fault() and do_anonymous_page(). In handle_pte_fault(), if vmf->pte is set (the original pte was not pte_none), catch speculative faults and return VM_FAULT_RETRY as those cases are not implemented yet. Also assert that do_fault() is not reached in the speculative case. Signed-off-by: Michel Lespinasse --- arch/x86/mm/fault.c | 2 +- mm/memory.c | 16 ++++++++++++---- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 99b0a358154e..6ba109413396 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -1334,7 +1334,7 @@ void do_user_addr_fault(struct pt_regs *regs, goto spf_abort; rcu_read_lock(); vma = __find_vma(mm, address); - if (!vma || vma->vm_start > address) { + if (!vma || vma->vm_start > address || !vma_is_anonymous(vma)) { rcu_read_unlock(); goto spf_abort; } diff --git a/mm/memory.c b/mm/memory.c index 8d036140634d..74b51aae8166 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4365,6 +4365,8 @@ static vm_fault_t do_fault(struct vm_fault *vmf) struct mm_struct *vm_mm = vma->vm_mm; vm_fault_t ret; + VM_BUG_ON(vmf->flags & FAULT_FLAG_SPECULATIVE); + /* * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */ @@ -4609,6 +4611,11 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) return do_fault(vmf); } + if (vmf->flags & FAULT_FLAG_SPECULATIVE) { + pte_unmap(vmf->pte); + return VM_FAULT_RETRY; + } + if (!pte_present(vmf->orig_pte)) return do_swap_page(vmf); @@ -4937,8 +4944,7 @@ vm_fault_t do_handle_mm_fault(struct vm_area_struct *vma, { vm_fault_t ret; - if (flags & FAULT_FLAG_SPECULATIVE) - return VM_FAULT_RETRY; + VM_BUG_ON((flags & FAULT_FLAG_SPECULATIVE) && !vma_is_anonymous(vma)); __set_current_state(TASK_RUNNING); @@ -4960,10 +4966,12 @@ vm_fault_t do_handle_mm_fault(struct vm_area_struct *vma, if (flags & FAULT_FLAG_USER) mem_cgroup_enter_user_fault(); - if (unlikely(is_vm_hugetlb_page(vma))) + if (unlikely(is_vm_hugetlb_page(vma))) { + VM_BUG_ON(flags & FAULT_FLAG_SPECULATIVE); ret = hugetlb_fault(vma->vm_mm, vma, address, flags); - else + } else { ret = __handle_mm_fault(vma, address, flags, seq); + } if (flags & FAULT_FLAG_USER) { mem_cgroup_exit_user_fault(); -- 2.20.1