From patchwork Mon Jul 24 18:54:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 13325248 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 67A37C00528 for ; Mon, 24 Jul 2023 18:54:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229770AbjGXSyY (ORCPT ); Mon, 24 Jul 2023 14:54:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229562AbjGXSyU (ORCPT ); Mon, 24 Jul 2023 14:54:20 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0757DE55 for ; Mon, 24 Jul 2023 11:54:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=Q+DaNTNbIUG3q6eDPG2po4w54RCX1zIfiIR5STu1uiQ=; b=IfZBEC2bafAFTQbS89y7UijEBE RWmQ1Ds4r4Jychulds5YnYRb3I0od+yIzxGEjRBg/sMoaW8Sgo39q598ZbCrb8yFJjLhEXLbKGw2u m6ON7coI8Vkyui8eqwVD3MAAI4b1SEwfQnyn3FGv9SQx1ziGML5H3GK5zcH+sBTO4lmFkaq0PKQyx xzo+xp/C7beutQOsWwV77qUovD+qADlO+56E/Dwyj29cWGg4lg7hX6Mo01FXPuux0JJUirC3kWWWp PlgvLemMPnSu3miVyRvcWhE2qw/Nw7f8SnbiBBb69OcutacNlt/2UeeoQC1+cppK2G6+2AMHfS7AU qU4S7HIA==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1qO0hA-004iRJ-S7; Mon, 24 Jul 2023 18:54:12 +0000 From: "Matthew Wilcox (Oracle)" To: Andrew Morton Cc: "Matthew Wilcox (Oracle)" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Punit Agrawal Subject: [PATCH v3 10/10] mm: Handle faults that merely update the accessed bit under the VMA lock Date: Mon, 24 Jul 2023 19:54:10 +0100 Message-Id: <20230724185410.1124082-11-willy@infradead.org> X-Mailer: git-send-email 2.37.1 In-Reply-To: <20230724185410.1124082-1-willy@infradead.org> References: <20230724185410.1124082-1-willy@infradead.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Move FAULT_FLAG_VMA_LOCK check out of handle_pte_fault(). This should have a significant performance improvement for mmaped files. Write faults (on read-only shared pages) still take the mmap lock as we do not want to audit all the implementations of ->pfn_mkwrite() and ->page_mkwrite(). However write-faults on private mappings are handled under the VMA lock. Signed-off-by: Matthew Wilcox (Oracle) --- mm/memory.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/mm/memory.c b/mm/memory.c index ad77ac7f8c9b..20a2e9ed4aeb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3393,6 +3393,11 @@ static vm_fault_t wp_pfn_shared(struct vm_fault *vmf) vm_fault_t ret; pte_unmap_unlock(vmf->pte, vmf->ptl); + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + vma_end_read(vmf->vma); + return VM_FAULT_RETRY; + } + vmf->flags |= FAULT_FLAG_MKWRITE; ret = vma->vm_ops->pfn_mkwrite(vmf); if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)) @@ -3415,6 +3420,12 @@ static vm_fault_t wp_page_shared(struct vm_fault *vmf, struct folio *folio) vm_fault_t tmp; pte_unmap_unlock(vmf->pte, vmf->ptl); + if (vmf->flags & FAULT_FLAG_VMA_LOCK) { + folio_put(folio); + vma_end_read(vmf->vma); + return VM_FAULT_RETRY; + } + tmp = do_page_mkwrite(vmf, folio); if (unlikely(!tmp || (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { @@ -5113,12 +5124,6 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf) if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma)) return do_numa_page(vmf); - if ((vmf->flags & FAULT_FLAG_VMA_LOCK) && !vma_is_anonymous(vmf->vma)) { - pte_unmap(vmf->pte); - vma_end_read(vmf->vma); - return VM_FAULT_RETRY; - } - spin_lock(vmf->ptl); entry = vmf->orig_pte; if (unlikely(!pte_same(ptep_get(vmf->pte), entry))) {