From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Christie Subject: Re: [PATCH 00/17] Swap-over-NBD without deadlocking V10 Date: Thu, 10 May 2012 12:17:01 -0500 Message-ID: <4FABF80D.3040803@cs.wisc.edu> References: <1336657510-24378-1-git-send-email-mgorman@suse.de> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="------------020903070100040605000103" Cc: Andrew Morton , Linux-MM , Linux-Netdev , LKML , David Miller , Neil Brown , Peter Zijlstra , Eric B Munson To: Mel Gorman Return-path: In-Reply-To: <1336657510-24378-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-Id: netdev.vger.kernel.org This is a multi-part message in MIME format. --------------020903070100040605000103 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit On 05/10/2012 08:44 AM, Mel Gorman wrote: > When a user or administrator requires swap for their application, they > create a swap partition and file, format it with mkswap and activate it > with swapon. Swap over the network is considered as an option in diskless > systems. The two likely scenarios are when blade servers are used as part > of a cluster where the form factor or maintenance costs do not allow the > use of disks and thin clients. Thank you for working on this. I made the attached patch for software iscsi which has the same issue as nbd. I tested the patch here and did not notice any performance regressions or any other bugs. --------------020903070100040605000103 Content-Type: text/plain; charset=UTF-8; name="0001-iscsi-Set-SOCK_MEMALLOC-for-access-to-PFMEMALLOC-res.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename*0="0001-iscsi-Set-SOCK_MEMALLOC-for-access-to-PFMEMALLOC-res.pa"; filename*1="tch" >>From 917d53f16d1e26b12e90e5e15df76a7a8bee35e8 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Thu, 3 May 2012 12:36:18 -0500 Subject: [PATCH 1/1] iscsi: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Set SOCK_MEMALLOC on the iscsi socket to allow access to PFMEMALLOC reserves to prevent deadlock. Signed-off-by: Mike Christie --- drivers/scsi/iscsi_tcp.c | 18 +++++++++++++----- 1 files changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c index 453a740..7360f4c 100644 --- a/drivers/scsi/iscsi_tcp.c +++ b/drivers/scsi/iscsi_tcp.c @@ -370,17 +370,24 @@ static inline int iscsi_sw_tcp_xmit_qlen(struct iscsi_conn *conn) static int iscsi_sw_tcp_pdu_xmit(struct iscsi_task *task) { struct iscsi_conn *conn = task->conn; - int rc; + unsigned long pflags = current->flags; + int rc = 0; + + current->flags |= PF_MEMALLOC; while (iscsi_sw_tcp_xmit_qlen(conn)) { rc = iscsi_sw_tcp_xmit(conn); - if (rc == 0) - return -EAGAIN; + if (rc == 0) { + rc = -EAGAIN; + break; + } if (rc < 0) - return rc; + break; + rc = 0; } - return 0; + tsk_restore_flags(current, pflags, PF_MEMALLOC); + return rc; } /* @@ -665,6 +672,7 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session, sk->sk_reuse = 1; sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */ sk->sk_allocation = GFP_ATOMIC; + sk_set_memalloc(sk); iscsi_sw_tcp_conn_set_callbacks(conn); tcp_sw_conn->sendpage = tcp_sw_conn->sock->ops->sendpage; -- 1.7.7.6 --------------020903070100040605000103-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org