From patchwork Thu Dec 16 23:48:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 12683091 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 26B55C433F5 for ; Thu, 16 Dec 2021 23:52:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96B4C6B0071; Thu, 16 Dec 2021 18:52:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8F46C6B0073; Thu, 16 Dec 2021 18:52:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 76D706B0074; Thu, 16 Dec 2021 18:52:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0230.hostedemail.com [216.40.44.230]) by kanga.kvack.org (Postfix) with ESMTP id 61FF96B0071 for ; Thu, 16 Dec 2021 18:52:25 -0500 (EST) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 2267D181AEF09 for ; Thu, 16 Dec 2021 23:52:15 +0000 (UTC) X-FDA: 78925308630.30.7D504E5 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf25.hostedemail.com (Postfix) with ESMTP id 3EACCA0008 for ; Thu, 16 Dec 2021 23:52:09 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 23A2C1F37E; Thu, 16 Dec 2021 23:52:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1639698733; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=BrMW3JyWaNdMJ0Haf3gWky2KOkmwQPIMXLocO6ojo8o=; b=DfXO/ARWHnOSgkR04rVeYWiJ00Np51WduldO55NRZGcnXX65SMlD74kOss6zNofHODwDgA 9lvaiLCv9vqHR8B9coVRJmVsJV4hrpsvFAI+ZRD8oySU+GPGwFbk2Sfi3fjxe611RZX2sy JJ58RW5XYx5L6c36qlay8m26Fik9QZg= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1639698733; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=BrMW3JyWaNdMJ0Haf3gWky2KOkmwQPIMXLocO6ojo8o=; b=6hWDofoY++geU4rja8Ev6OXOahSMjRP23VYgJmDPJZuctOB7qpBjTDQv6xmt0cSPnEqJjA nJp1F5+SG8xxooBw== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id F1B5113EFD; Thu, 16 Dec 2021 23:52:09 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id XNGLKSnRu2EvWwAAMHmgww (envelope-from ); Thu, 16 Dec 2021 23:52:09 +0000 Subject: [PATCH 00/18 V2] Repair SWAP-over-NFS From: NeilBrown To: Trond Myklebust , Anna Schumaker , Chuck Lever , Andrew Morton , Mel Gorman , Christoph Hellwig , David Howells Cc: linux-nfs@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Fri, 17 Dec 2021 10:48:22 +1100 Message-ID: <163969801519.20885.3977673503103544412.stgit@noble.brown> User-Agent: StGit/0.23 MIME-Version: 1.0 X-Rspamd-Queue-Id: 3EACCA0008 X-Stat-Signature: cdo5hq58t5dfr7o5bfa5w8k8huoxb6sm Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=suse.de header.s=susede2_rsa header.b="DfXO/ARW"; dkim=pass header.d=suse.de header.s=susede2_ed25519 header.b=6hWDofoY; dmarc=pass (policy=none) header.from=suse.de; spf=pass (imf25.hostedemail.com: domain of neilb@suse.de designates 195.135.220.29 as permitted sender) smtp.mailfrom=neilb@suse.de X-Rspamd-Server: rspam11 X-HE-Tag: 1639698729-288475 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: swap-over-NFS currently has a variety of problems. swap writes call generic_write_checks(), which always fails on a swap file, so it completely fails. Even without this, various deadlocks are possible - largely due to improvements in NFS memory allocation (using NOFS instead of ATOMIC) which weren't tested against swap-out. NFS is the only filesystem that has supported fs-based swap IO, and it hasn't worked for several releases, so now is a convenient time to clean up the swap-via-filesystem interfaces - we cannot break anything ! So the first few patches here clean up and improve various parts of the swap-via-filesystem code. ->activate_swap() is given a cleaner interface, a new ->swap_rw is introduced instead of burdening ->direct_IO, etc. Current swap-to-filesystem code only ever submits single-page reads and writes. These patches change that to allow multi-page IO when adjacent requests are submitted. Writes are also changed to be async rather than sync. This substantially speeds up write throughput for swap-over-NFS. Some of the NFS patches can land independently of the MM patches. A few require the MM patches to land first. Thanks, NeilBrown --- NeilBrown (18): Structural cleanup for filesystem-based swap MM: create new mm/swap.h header file. MM: use ->swap_rw for reads from SWP_FS_OPS swap-space MM: perform async writes to SWP_FS_OPS swap-space MM: reclaim mustn't enter FS for SWP_FS_OPS swap-space MM: submit multipage reads for SWP_FS_OPS swap-space MM: submit multipage write for SWP_FS_OPS swap-space MM: Add AS_CAN_DIO mapping flag NFS: rename nfs_direct_IO and use as ->swap_rw NFS: swap IO handling is slightly different for O_DIRECT IO SUNRPC/call_alloc: async tasks mustn't block waiting for memory SUNRPC/auth: async tasks mustn't block waiting for memory SUNRPC/xprt: async tasks mustn't block waiting for memory SUNRPC: remove scheduling boost for "SWAPPER" tasks. NFS: discard NFS_RPC_SWAPFLAGS and RPC_TASK_ROOTCREDS SUNRPC: improve 'swap' handling: scheduling and PF_MEMALLOC NFSv4: keep state manager thread active if swap is enabled NFS: swap-out must always use STABLE writes. drivers/block/loop.c | 4 +- fs/fcntl.c | 5 +- fs/inode.c | 3 + fs/nfs/direct.c | 56 ++++++---- fs/nfs/file.c | 25 +++-- fs/nfs/inode.c | 1 + fs/nfs/nfs4_fs.h | 1 + fs/nfs/nfs4proc.c | 20 ++++ fs/nfs/nfs4state.c | 39 ++++++- fs/nfs/read.c | 4 - fs/nfs/write.c | 2 + fs/open.c | 2 +- fs/overlayfs/file.c | 10 +- include/linux/fs.h | 2 +- include/linux/nfs_fs.h | 11 +- include/linux/nfs_xdr.h | 2 + include/linux/pagemap.h | 3 +- include/linux/sunrpc/auth.h | 1 + include/linux/sunrpc/sched.h | 1 - include/linux/swap.h | 121 -------------------- include/linux/writeback.h | 7 ++ include/trace/events/sunrpc.h | 1 - mm/madvise.c | 9 +- mm/memory.c | 3 +- mm/mincore.c | 1 + mm/page_alloc.c | 1 + mm/page_io.c | 189 ++++++++++++++++++++++++++------ mm/shmem.c | 1 + mm/swap.h | 140 +++++++++++++++++++++++ mm/swap_state.c | 32 ++++-- mm/swapfile.c | 6 + mm/util.c | 1 + mm/vmscan.c | 31 +++++- net/sunrpc/auth.c | 8 +- net/sunrpc/auth_gss/auth_gss.c | 6 +- net/sunrpc/auth_unix.c | 10 +- net/sunrpc/clnt.c | 7 +- net/sunrpc/sched.c | 29 +++-- net/sunrpc/xprt.c | 19 ++-- net/sunrpc/xprtrdma/transport.c | 10 +- net/sunrpc/xprtsock.c | 8 ++ 41 files changed, 558 insertions(+), 274 deletions(-) create mode 100644 mm/swap.h -- Signature