Thread (16 messages) 16 messages, 2 authors, 2012-06-28

Re: [PATCH 10/12] nfs: enable swap on NFS

From: Jeff Layton <hidden>
Date: 2012-06-28 12:50:47
Also in: linux-mm, linux-nfs, lkml

On Thu, 28 Jun 2012 13:37:34 +0100
Mel Gorman [off-list ref] wrote:
quoted hunk ↗ jump to hunk
On Thu, Jun 28, 2012 at 08:27:25AM -0400, Jeff Layton wrote:
quoted
quoted
<SNIP>
@@ -2108,11 +2156,15 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 		container_of(work, struct sock_xprt, connect_worker.work);
 	struct socket *sock = transport->sock;
 	struct rpc_xprt *xprt = &transport->xprt;
+	unsigned long pflags = current->flags;
 	int status = -EIO;
 
 	if (xprt->shutdown)
 		goto out;
 
+	if (xprt->swapper)
+		current->flags |= PF_MEMALLOC;
+
 	if (!sock) {
 		clear_bit(XPRT_CONNECTION_ABORT, &xprt->state);
 		sock = xs_create_sock(xprt, transport,
@@ -2174,6 +2226,7 @@ out_eagain:
 out:
 	xprt_clear_connecting(xprt);
 	xprt_wake_pending_tasks(xprt, status);
+	tsk_restore_flags(current, pflags, PF_MEMALLOC);
 }
 
 /**
Apologies if this is fixed in another patch and I didn't see it...
No apologies necessary. Even if it was fixed in another patch, it would
still be wrong for bisection reasons and for being rude to reviewers.
quoted
There's a place in the above function that returns without going
through "out:". I think you also want to tsk_restore_flags() in that
spot too.
You're right. The case that it would trigger would be some corner case
but very nicely spotted.
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index b84df34..3d58b92 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2214,6 +2214,7 @@ static void xs_tcp_setup_socket(struct work_struct *work)
 	case -EINPROGRESS:
 	case -EALREADY:
 		xprt_clear_connecting(xprt);
+		tsk_restore_flags(current, pflags, PF_MEMALLOC);
 		return;
 	case -EINVAL:
 		/* Happens, for instance, if the user specified a link
That looks correct.

Actually it's not obvious in this function, but it turns out that this
is the common case. xs_tcp_finish_connecting calls kernel_connect with
O_NONBLOCK set, and that almost always immediately returns with
-EINPROGRESS.

Cheers,
-- 
Jeff Layton [off-list ref]

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