From patchwork Wed Jun 28 10:48:50 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 13295555 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 72C38EB64DC for ; Wed, 28 Jun 2023 10:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230128AbjF1Ktx (ORCPT ); Wed, 28 Jun 2023 06:49:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:29666 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230413AbjF1Ktp (ORCPT ); Wed, 28 Jun 2023 06:49:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1687949338; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=+QydiwIjN9aTPx/xjudDhfoGuS6UX8G9SMmj+YNOpRA=; b=XN7JBBS6tT70q4G6SB6ZlZXVLgO9FsA4eFY1UMJamdstKs27vqvnyp7YWp8KmB1OnzVQZs G0nwVqpceYhXlHvmNTdjz/b82DwaKOvl3eNkactGATkQHf80xWBzKwfWpHi5MoWBUFMvcU 7ZHKCKXP+8t4pz+FS6fqdq9mqMRN9Pg= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-508-vLNGNocHNsqPW492eEhOXw-1; Wed, 28 Jun 2023 06:48:57 -0400 X-MC-Unique: vLNGNocHNsqPW492eEhOXw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C298E3810D42; Wed, 28 Jun 2023 10:48:56 +0000 (UTC) Received: from warthog.procyon.org.uk.com (unknown [10.42.28.4]) by smtp.corp.redhat.com (Postfix) with ESMTP id 25EC6200B677; Wed, 28 Jun 2023 10:48:55 +0000 (UTC) From: David Howells To: Andrew Morton Cc: David Howells , Matthew Wilcox , Linus Torvalds , Jeff Layton , Christoph Hellwig , linux-afs@lists.infradead.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, v9fs-developer@lists.sourceforge.net, linux-erofs@lists.ozlabs.org, linux-ext4@vger.kernel.org, linux-cachefs@redhat.com, linux-fsdevel@vger.kernel.org Subject: [PATCH v7 0/2] mm, netfs, fscache: Stop read optimisation when folio removed from pagecache Date: Wed, 28 Jun 2023 11:48:50 +0100 Message-ID: <20230628104852.3391651-1-dhowells@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: ceph-devel@vger.kernel.org Hi Andrew, Should this go through the mm tree? This fixes an optimisation in fscache whereby we don't read from the cache for a particular file until we know that there's data there that we don't have in the pagecache. The problem is that I'm no longer using PG_fscache (aka PG_private_2) to indicate that the page is cached and so I don't get a notification when a cached page is dropped from the pagecache. The first patch merges some folio_has_private() and filemap_release_folio() pairs and introduces a helper, folio_needs_release(), to indicate if a release is required. The second patch is the actual fix. Following Willy's suggestions[1], it adds an AS_RELEASE_ALWAYS flag to an address_space that will make filemap_release_folio() always call ->release_folio(), even if PG_private/PG_private_2 aren't set. folio_needs_release() is altered to add a check for this. David Changes: ======== ver #7) - Make NFS set AS_RELEASE_ALWAYS. ver #6) - Drop the third patch which removes a duplicate check in vmscan(). ver #5) - Rebased on linus/master. try_to_release_page() has now been entirely replaced by filemap_release_folio(), barring one comment. - Cleaned up some pairs in ext4. ver #4) - Split has_private/release call pairs into own patch. - Moved folio_needs_release() to mm/internal.h and removed open-coded version from filemap_release_folio(). - Don't need to clear AS_RELEASE_ALWAYS in ->evict_inode(). - Added experimental patch to reduce shrink_folio_list(). ver #3) - Fixed mapping_clear_release_always() to use clear_bit() not set_bit(). - Moved a '&&' to the correct line. ver #2) - Rewrote entirely according to Willy's suggestion[1]. Link: https://lore.kernel.org/r/Yk9V/03wgdYi65Lb@casper.infradead.org/ [1] Link: https://lore.kernel.org/r/164928630577.457102.8519251179327601178.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/166844174069.1124521.10890506360974169994.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/166869495238.3720468.4878151409085146764.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/1459152.1669208550@warthog.procyon.org.uk/ # v3 also Link: https://lore.kernel.org/r/166924370539.1772793.13730698360771821317.stgit@warthog.procyon.org.uk/ # v4 Link: https://lore.kernel.org/r/167172131368.2334525.8569808925687731937.stgit@warthog.procyon.org.uk/ # v5 Link: https://lore.kernel.org/r/20230216150701.3654894-1-dhowells@redhat.com/ # v6 David Howells (2): mm: Merge folio_has_private()/filemap_release_folio() call pairs mm, netfs, fscache: Stop read optimisation when folio removed from pagecache fs/9p/cache.c | 2 ++ fs/afs/internal.h | 2 ++ fs/cachefiles/namei.c | 2 ++ fs/ceph/cache.c | 2 ++ fs/ext4/move_extent.c | 12 ++++-------- fs/nfs/fscache.c | 3 +++ fs/smb/client/fscache.c | 2 ++ fs/splice.c | 3 +-- include/linux/pagemap.h | 16 ++++++++++++++++ mm/filemap.c | 2 ++ mm/huge_memory.c | 3 +-- mm/internal.h | 11 +++++++++++ mm/khugepaged.c | 3 +-- mm/memory-failure.c | 8 +++----- mm/migrate.c | 3 +-- mm/truncate.c | 6 ++---- mm/vmscan.c | 8 ++++---- 17 files changed, 59 insertions(+), 29 deletions(-)