Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762100Ab2EQOu6 (ORCPT ); Thu, 17 May 2012 10:50:58 -0400 Received: from cantor2.suse.de ([195.135.220.15]:33461 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762064Ab2EQOut (ORCPT ); Thu, 17 May 2012 10:50:49 -0400 From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Mike Christie , Eric B Munson , Mel Gorman Subject: [PATCH 15/17] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Date: Thu, 17 May 2012 15:50:29 +0100 Message-Id: <1337266231-8031-16-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1337266231-8031-1-git-send-email-mgorman@suse.de> References: <1337266231-8031-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2025 Lines: 59 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) { -- 1.7.9.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/