From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Fri, 25 Aug 2006 17:40:27 +0200 Message-Id: <20060825154027.24271.43168.sendpatchset@twins> In-Reply-To: <20060825153946.24271.42758.sendpatchset@twins> References: <20060825153946.24271.42758.sendpatchset@twins> Subject: [PATCH 4/4] nfs: deadlock prevention for NFS Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Cc: Indan Zupancic , Peter Zijlstra , Evgeniy Polyakov , Daniel Phillips , Rik van Riel , David Miller List-ID: Provide a proper a_ops->swapfile() implementation for NFS. This will set the NFS socket to SOCK_VMIO and put the socket reconnection under PF_MEMALLOC (I hope this is enough, otherwise more work needs to be done). Signed-off-by: Peter Zijlstra --- fs/nfs/file.c | 21 ++++++++++++++++++++- include/linux/sunrpc/xprt.h | 4 +++- net/sunrpc/xprtsock.c | 16 ++++++++++++++++ 3 files changed, 39 insertions(+), 2 deletions(-) Index: linux-2.6/fs/nfs/file.c =================================================================== --- linux-2.6.orig/fs/nfs/file.c +++ linux-2.6/fs/nfs/file.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -317,7 +318,25 @@ static int nfs_release_page(struct page static int nfs_swapfile(struct address_space *mapping, int enable) { - return 0; + int err = -EINVAL; + struct rpc_clnt *client = NFS_CLIENT(mapping->host); + struct sock *sk = client->cl_xprt->inet; + + if (enable) { + client->cl_xprt->swapper = 1; + /* + * keep one extra sock reference so the reserve won't dip + * when the socket gets reconnected. + */ + sk_adjust_memalloc(1, 1); + err = sk_set_vmio(sk); + } else if (client->cl_xprt->swapper) { + client->cl_xprt->swapper = 0; + sk_adjust_memalloc(-1, -1); + err = sk_clear_vmio(sk); + } + + return err; } const struct address_space_operations nfs_file_aops = { Index: linux-2.6/net/sunrpc/xprtsock.c =================================================================== --- linux-2.6.orig/net/sunrpc/xprtsock.c +++ linux-2.6/net/sunrpc/xprtsock.c @@ -1014,6 +1014,7 @@ static void xs_udp_connect_worker(void * { struct rpc_xprt *xprt = (struct rpc_xprt *) args; struct socket *sock = xprt->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || xprt->addr.sin_port == 0) @@ -1021,6 +1022,9 @@ static void xs_udp_connect_worker(void * dprintk("RPC: xs_udp_connect_worker for xprt %p\n", xprt); + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + /* Start by resetting any existing state */ xs_close(xprt); @@ -1054,6 +1058,9 @@ static void xs_udp_connect_worker(void * xprt->sock = sock; xprt->inet = sk; + if (xprt->swapper) + sk_set_vmio(sk); + write_unlock_bh(&sk->sk_callback_lock); } xs_udp_do_set_buffer_size(xprt); @@ -1061,6 +1068,7 @@ static void xs_udp_connect_worker(void * out: xprt_wake_pending_tasks(xprt, status); xprt_clear_connecting(xprt); + current->flags = pflags; } /* @@ -1097,11 +1105,15 @@ static void xs_tcp_connect_worker(void * { struct rpc_xprt *xprt = (struct rpc_xprt *)args; struct socket *sock = xprt->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || xprt->addr.sin_port == 0) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + dprintk("RPC: xs_tcp_connect_worker for xprt %p\n", xprt); if (!xprt->sock) { @@ -1170,10 +1182,14 @@ static void xs_tcp_connect_worker(void * break; } } + + if (xprt->swapper) + sk_set_vmio(xprt->inet); out: xprt_wake_pending_tasks(xprt, status); out_clear: xprt_clear_connecting(xprt); + current->flags = pflags; } /** Index: linux-2.6/include/linux/sunrpc/xprt.h =================================================================== --- linux-2.6.orig/include/linux/sunrpc/xprt.h +++ linux-2.6/include/linux/sunrpc/xprt.h @@ -147,7 +147,9 @@ struct rpc_xprt { unsigned int max_reqs; /* total slots */ unsigned long state; /* transport state */ unsigned char shutdown : 1, /* being shut down */ - resvport : 1; /* use a reserved port */ + resvport : 1, /* use a reserved port */ + swapper : 1; /* we're swapping over this + transport */ /* * XID -- 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/ . Don't email: email@kvack.org