From patchwork Fri Jun 29 13:32:45 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mel Gorman X-Patchwork-Id: 168093 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 4051CB6FA3 for ; Fri, 29 Jun 2012 23:39:30 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932224Ab2F2Niz (ORCPT ); Fri, 29 Jun 2012 09:38:55 -0400 Received: from cantor2.suse.de ([195.135.220.15]:45534 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755112Ab2F2NdH (ORCPT ); Fri, 29 Jun 2012 09:33:07 -0400 Received: from relay2.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 7FABBA4E82; Fri, 29 Jun 2012 15:33:06 +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: Fri, 29 Jun 2012 14:32:45 +0100 Message-Id: <1340976767-5737-15-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1340976767-5737-1-git-send-email-mgorman@suse.de> References: <1340976767-5737-1-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) {