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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 61313C282CB for ; Tue, 5 Feb 2019 10:23:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 34AAC2083B for ; Tue, 5 Feb 2019 10:23:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728117AbfBEKXM (ORCPT ); Tue, 5 Feb 2019 05:23:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51028 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727652AbfBEKXM (ORCPT ); Tue, 5 Feb 2019 05:23:12 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 3DACD3C2CCF; Tue, 5 Feb 2019 10:23:12 +0000 (UTC) Received: from [172.16.176.1] (ovpn-112-2.rdu2.redhat.com [10.10.112.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4A4C060F8A; Tue, 5 Feb 2019 10:23:10 +0000 (UTC) From: "Benjamin Coddington" To: "Trond Myklebust" Cc: anna.schumaker@netapp.com, linux-nfs@vger.kernel.org Subject: Re: [PATCH] NFS: Don't use page_file_mapping after removing the page Date: Tue, 05 Feb 2019 05:23:08 -0500 Message-ID: In-Reply-To: <602aa0cc867676254cf09d6e329eb6a8f7345920.camel@hammerspace.com> References: <22D43CDC-BB14-4C8F-A10E-DF7816EBF0B0@redhat.com> <9857F7D4-FA2E-43D0-8D4B-4C753A81687C@redhat.com> <628931F4-B625-4430-96FF-268CF926934A@redhat.com> <602aa0cc867676254cf09d6e329eb6a8f7345920.camel@hammerspace.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Tue, 05 Feb 2019 10:23:12 +0000 (UTC) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org On 4 Feb 2019, at 16:40, Trond Myklebust wrote: > What about the case when the page is in the swap cache? Is that also > safe? I think the case you'd like me to consider is when a file on NFS has its mapping backed by pages that are in swap. In that case, it makes no sense to check the count of pages in the swap file's mapping to determine whether to set NFS_INO_INVALID_DATA. We actually want to optimize away the revalidation if the NFS file lacks mapped pages. Ben