From patchwork Thu Jul 12 06:40:30 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 170565 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 6627D2C0088 for ; Thu, 12 Jul 2012 16:47:24 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758730Ab2GLGrG (ORCPT ); Thu, 12 Jul 2012 02:47:06 -0400 Received: from cantor2.suse.de ([195.135.220.15]:39899 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758690Ab2GLGkx (ORCPT ); Thu, 12 Jul 2012 02:40:53 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id EAF3DA45F9; Thu, 12 Jul 2012 08:40:52 +0200 (CEST) From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Eric Dumazet , Sebastian Andrzej Siewior , Mel Gorman Subject: [PATCH 14/16] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Date: Thu, 12 Jul 2012 07:40:30 +0100 Message-Id: <1342075232-29267-15-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1342075232-29267-1-git-send-email-mgorman@suse.de> References: <1342075232-29267-1-git-send-email-mgorman@suse.de> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Set SOCK_MEMALLOC on the NBD socket to allow access to PFMEMALLOC reserves so pages backed by NBD, particularly if swap related, can be cleaned to prevent the machine being deadlocked. It is still possible that the PFMEMALLOC reserves get depleted resulting in deadlock but this can be resolved by the administrator by increasing min_free_kbytes. Signed-off-by: Mel Gorman --- drivers/block/nbd.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 061427a75d..76bc96f 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -154,6 +154,7 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, struct msghdr msg; struct kvec iov; sigset_t blocked, oldset; + unsigned long pflags = current->flags; if (unlikely(!sock)) { dev_err(disk_to_dev(nbd->disk), @@ -167,8 +168,9 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, siginitsetinv(&blocked, sigmask(SIGKILL)); sigprocmask(SIG_SETMASK, &blocked, &oldset); + current->flags |= PF_MEMALLOC; do { - sock->sk->sk_allocation = GFP_NOIO; + sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC; iov.iov_base = buf; iov.iov_len = size; msg.msg_name = NULL; @@ -214,6 +216,7 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size, } while (size > 0); sigprocmask(SIG_SETMASK, &oldset, NULL); + tsk_restore_flags(current, pflags, PF_MEMALLOC); return result; } @@ -405,6 +408,7 @@ static int nbd_do_it(struct nbd_device *nbd) BUG_ON(nbd->magic != NBD_MAGIC); + sk_set_memalloc(nbd->sock->sk); nbd->pid = task_pid_nr(current); ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr); if (ret) {