From patchwork Mon Jul 23 17:58:51 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jeff Layton X-Patchwork-Id: 1228451 Return-Path: X-Original-To: patchwork-linux-nfs@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 6BDD940D35 for ; Mon, 23 Jul 2012 17:59:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754543Ab2GWR7H (ORCPT ); Mon, 23 Jul 2012 13:59:07 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:42459 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753473Ab2GWR66 (ORCPT ); Mon, 23 Jul 2012 13:58:58 -0400 Received: by gglu4 with SMTP id u4so5754374ggl.19 for ; Mon, 23 Jul 2012 10:58:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer :x-gm-message-state; bh=pExdVNQusXynsAVi0tSVHqR7f7dEGW5611AA+rI6zw4=; b=JVX95k1iaaYaxNnIRf3NlWmCjs63G5ywMHm/Md4tYIgttwLaJn8pRLDWPfo9pWoIma cxFpiHvMLh+A0VnqnUqkbAOd7So9O2drTW8JNNgf/b0BuSILoMIyr0Ii+LDmHJAs7qxf 1eIVlGgonY9040g0AouPTIOLYGPRQ92ye96nEP66dioXWUFxSnrZopP+4yfJ4mpuRQz9 VMX9gswyxXSK+4yDg6taPyZ5DGwaKje+wxoqvarEGxHJA8j6jabOxZNt/h0aatSKcwNe H6VNSBxcH4CEv5zBe/Qh/Ge1v2p9tWnphxbkr4+A+BidmDOrSz3g7tXciQOQfAYFtbw+ gVgQ== Received: by 10.236.197.5 with SMTP id s5mr15323791yhn.114.1343066337329; Mon, 23 Jul 2012 10:58:57 -0700 (PDT) Received: from salusa.poochiereds.net (cpe-076-182-054-194.nc.res.rr.com. [76.182.54.194]) by mx.google.com with ESMTPS id y66sm26198287yhi.10.2012.07.23.10.58.55 (version=SSLv3 cipher=OTHER); Mon, 23 Jul 2012 10:58:55 -0700 (PDT) From: Jeff Layton To: trond.myklebust@netapp.com Cc: linux-nfs@vger.kernel.org Subject: [PATCH] nfs: skip commit in releasepage if we're freeing memory for fs-related reasons Date: Mon, 23 Jul 2012 13:58:51 -0400 Message-Id: <1343066331-26509-1-git-send-email-jlayton@redhat.com> X-Mailer: git-send-email 1.7.10.4 X-Gm-Message-State: ALoCoQnucOJbG1/UKsr7DUJB7+fFr/3H0cLlE1J3G9iv3D4xH6+8r5Tu8I4RmZwpF9OUO7iV4mr8 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org We've had some reports of a deadlock where rpciod ends up with a stack trace like this: PID: 2507 TASK: ffff88103691ab40 CPU: 14 COMMAND: "rpciod/14" #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9 #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs] #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8 #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs] #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs] #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670 #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271 #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638 #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942 #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9 #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808 #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6 #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7 #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc] #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc] #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0 #24 [ffff8810343bfee8] kthread at ffffffff8108dd96 #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca rpciod is trying to allocate memory for a new socket to talk to the server. The VM ends up calling ->releasepage to get more memory, and it tries to do a blocking commit. That commit can't succeed however without a connected socket, so we deadlock. Fix this by setting PF_FSTRANS on the workqueue task prior to doing the socket allocation, and having nfs_release_page check for that flag when deciding whether to do a commit call. Also, set PF_FSTRANS unconditionally in rpc_async_schedule since that function can also do allocations sometimes. Signed-off-by: Jeff Layton --- fs/nfs/file.c | 7 +++++-- net/sunrpc/sched.c | 2 ++ net/sunrpc/xprtrdma/transport.c | 3 ++- net/sunrpc/xprtsock.c | 10 ++++++++++ 4 files changed, 19 insertions(+), 3 deletions(-) diff --git a/fs/nfs/file.c b/fs/nfs/file.c index a6708e6b..9075769 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -459,8 +459,11 @@ static int nfs_release_page(struct page *page, gfp_t gfp) dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); - /* Only do I/O if gfp is a superset of GFP_KERNEL */ - if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL) { + /* Only do I/O if gfp is a superset of GFP_KERNEL, and we're not + * doing this memory reclaim for a fs-related allocation. + */ + if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL && + !(current->flags & PF_FSTRANS)) { int how = FLUSH_SYNC; /* Don't let kswapd deadlock waiting for OOM RPC calls */ diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 994cfea..eda32ae 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -790,7 +790,9 @@ void rpc_execute(struct rpc_task *task) static void rpc_async_schedule(struct work_struct *work) { + current->flags |= PF_FSTRANS; __rpc_execute(container_of(work, struct rpc_task, u.tk_work)); + current->flags &= ~PF_FSTRANS; } /** diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index b446e10..06cdbff 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -200,6 +200,7 @@ xprt_rdma_connect_worker(struct work_struct *work) int rc = 0; if (!xprt->shutdown) { + current->flags |= PF_FSTRANS; xprt_clear_connected(xprt); dprintk("RPC: %s: %sconnect\n", __func__, @@ -212,10 +213,10 @@ xprt_rdma_connect_worker(struct work_struct *work) out: xprt_wake_pending_tasks(xprt, rc); - out_clear: dprintk("RPC: %s: exit\n", __func__); xprt_clear_connecting(xprt); + current->flags &= ~PF_FSTRANS; } /* diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 890b03f..b88c6bf 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1895,6 +1895,8 @@ static void xs_local_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); status = __sock_create(xprt->xprt_net, AF_LOCAL, SOCK_STREAM, 0, &sock, 1); @@ -1928,6 +1930,7 @@ static void xs_local_setup_socket(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock) @@ -1970,6 +1973,8 @@ static void xs_udp_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + /* Start by resetting any existing state */ xs_reset_transport(transport); sock = xs_create_sock(xprt, transport, @@ -1988,6 +1993,7 @@ static void xs_udp_setup_socket(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } /* @@ -2113,6 +2119,8 @@ static void xs_tcp_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + if (!sock) { clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); sock = xs_create_sock(xprt, transport, @@ -2162,6 +2170,7 @@ static void xs_tcp_setup_socket(struct work_struct *work) case -EINPROGRESS: case -EALREADY: xprt_clear_connecting(xprt); + current->flags &= ~PF_FSTRANS; return; case -EINVAL: /* Happens, for instance, if the user specified a link @@ -2174,6 +2183,7 @@ out_eagain: out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } /**