Provide an a_ops->swapfile() implementation for NFS. This will set the NFS socket to SOCK_MEMALLOC and run socket reconnect under PF_MEMALLOC as well as reset SOCK_MEMALLOC before engaging the protocol ->connect() method. PF_MEMALLOC should allow the allocation of struct socket and related objects and the early (re)setting of SOCK_MEMALLOC should allow us to receive the packets required for the TCP connection buildup. (swapping continues over a server reset during heavy network traffic) Signed-off-by: Peter Zijlstra --- fs/Kconfig | 18 ++++++++++++ fs/nfs/file.c | 10 ++++++ include/linux/sunrpc/xprt.h | 5 ++- net/sunrpc/sched.c | 9 ++++-- net/sunrpc/xprtsock.c | 63 ++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 102 insertions(+), 3 deletions(-) Index: linux-2.6/fs/nfs/file.c =================================================================== --- linux-2.6.orig/fs/nfs/file.c +++ linux-2.6/fs/nfs/file.c @@ -371,6 +371,13 @@ static int nfs_launder_page(struct page return nfs_wb_page(page_file_mapping(page)->host, page); } +#ifdef CONFIG_NFS_SWAP +static int nfs_swapfile(struct address_space *mapping, int enable) +{ + return xs_swapper(NFS_CLIENT(mapping->host)->cl_xprt, enable); +} +#endif + const struct address_space_operations nfs_file_aops = { .readpage = nfs_readpage, .readpages = nfs_readpages, @@ -385,6 +392,9 @@ const struct address_space_operations nf .direct_IO = nfs_direct_IO, #endif .launder_page = nfs_launder_page, +#ifdef CONFIG_NFS_SWAP + .swapfile = nfs_swapfile, +#endif }; static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page) 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 @@ -143,7 +143,9 @@ 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 */ unsigned int bind_index; /* bind function index */ /* @@ -246,6 +248,7 @@ struct rpc_rqst * xprt_lookup_rqst(struc void xprt_complete_rqst(struct rpc_task *task, int copied); void xprt_release_rqst_cong(struct rpc_task *task); void xprt_disconnect(struct rpc_xprt *xprt); +int xs_swapper(struct rpc_xprt *xprt, int enable); /* * Reserved bit positions in xprt->state Index: linux-2.6/net/sunrpc/sched.c =================================================================== --- linux-2.6.orig/net/sunrpc/sched.c +++ linux-2.6/net/sunrpc/sched.c @@ -761,7 +761,10 @@ struct rpc_buffer { void *rpc_malloc(struct rpc_task *task, size_t size) { struct rpc_buffer *buf; - gfp_t gfp = RPC_IS_SWAPPER(task) ? GFP_ATOMIC : GFP_NOWAIT; + gfp_t gfp = GFP_NOWAIT; + + if (RPC_IS_SWAPPER(task)) + gfp |= __GFP_MEMALLOC; size += sizeof(struct rpc_buffer); if (size <= RPC_BUFFER_MAXSIZE) @@ -817,6 +820,8 @@ void rpc_init_task(struct rpc_task *task atomic_set(&task->tk_count, 1); task->tk_client = clnt; task->tk_flags = flags; + if (clnt->cl_xprt->swapper) + task->tk_flags |= RPC_TASK_SWAPPER; task->tk_ops = tk_ops; if (tk_ops->rpc_call_prepare != NULL) task->tk_action = rpc_prepare_task; @@ -853,7 +858,7 @@ void rpc_init_task(struct rpc_task *task static struct rpc_task * rpc_alloc_task(void) { - return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOFS); + return (struct rpc_task *)mempool_alloc(rpc_task_mempool, GFP_NOIO); } static void rpc_free_task(struct rcu_head *rcu) Index: linux-2.6/net/sunrpc/xprtsock.c =================================================================== --- linux-2.6.orig/net/sunrpc/xprtsock.c +++ linux-2.6/net/sunrpc/xprtsock.c @@ -1397,6 +1397,9 @@ static void xs_udp_finish_connecting(str transport->sock = sock; transport->inet = sk; + if (xprt->swapper) + sk_set_memalloc(sk); + write_unlock_bh(&sk->sk_callback_lock); } xs_udp_do_set_buffer_size(xprt); @@ -1414,11 +1417,15 @@ static void xs_udp_connect_worker4(struc container_of(work, struct sock_xprt, connect_worker.work); struct rpc_xprt *xprt = &transport->xprt; struct socket *sock = transport->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || !xprt_bound(xprt)) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + /* Start by resetting any existing state */ xs_close(xprt); @@ -1441,6 +1448,7 @@ static void xs_udp_connect_worker4(struc out: xprt_wake_pending_tasks(xprt, status); xprt_clear_connecting(xprt); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /** @@ -1455,11 +1463,15 @@ static void xs_udp_connect_worker6(struc container_of(work, struct sock_xprt, connect_worker.work); struct rpc_xprt *xprt = &transport->xprt; struct socket *sock = transport->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || !xprt_bound(xprt)) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + /* Start by resetting any existing state */ xs_close(xprt); @@ -1482,6 +1494,7 @@ static void xs_udp_connect_worker6(struc out: xprt_wake_pending_tasks(xprt, status); xprt_clear_connecting(xprt); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /* @@ -1541,6 +1554,9 @@ static int xs_tcp_finish_connecting(stru write_unlock_bh(&sk->sk_callback_lock); } + if (xprt->swapper) + sk_set_memalloc(transport->inet); + /* Tell the socket layer to start connecting... */ xprt->stat.connect_count++; xprt->stat.connect_start = jiffies; @@ -1559,11 +1575,15 @@ static void xs_tcp_connect_worker4(struc container_of(work, struct sock_xprt, connect_worker.work); struct rpc_xprt *xprt = &transport->xprt; struct socket *sock = transport->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || !xprt_bound(xprt)) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + if (!sock) { /* start from scratch */ if ((err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) { @@ -1606,6 +1626,7 @@ out: xprt_wake_pending_tasks(xprt, status); out_clear: xprt_clear_connecting(xprt); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /** @@ -1620,11 +1641,15 @@ static void xs_tcp_connect_worker6(struc container_of(work, struct sock_xprt, connect_worker.work); struct rpc_xprt *xprt = &transport->xprt; struct socket *sock = transport->sock; + unsigned long pflags = current->flags; int err, status = -EIO; if (xprt->shutdown || !xprt_bound(xprt)) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + if (!sock) { /* start from scratch */ if ((err = sock_create_kern(PF_INET6, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) { @@ -1666,6 +1691,7 @@ out: xprt_wake_pending_tasks(xprt, status); out_clear: xprt_clear_connecting(xprt); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /** @@ -1985,6 +2011,43 @@ int init_socket_xprt(void) return 0; } +#ifdef CONFIG_SUNRPC_SWAP +#define RPC_BUF_RESERVE_PAGES \ + kestimate_single(sizeof(struct rpc_rqst), GFP_KERNEL, RPC_MAX_SLOT_TABLE) +#define RPC_RESERVE_PAGES (RPC_BUF_RESERVE_PAGES + TX_RESERVE_PAGES) + +/** + * xs_swapper - Tag this transport as being used for swap. + * @xprt: transport to tag + * @enable: enable/disable + * + */ +int xs_swapper(struct rpc_xprt *xprt, int enable) +{ + struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt); + int err = 0; + + if (enable) { + /* + * keep one extra sock reference so the reserve won't dip + * when the socket gets reconnected. + */ + err = sk_adjust_memalloc(1, RPC_RESERVE_PAGES); + if (!err) { + sk_set_memalloc(transport->inet); + xprt->swapper = 1; + } + } else if (xprt->swapper) { + xprt->swapper = 0; + sk_clear_memalloc(transport->inet); + sk_adjust_memalloc(-1, -RPC_RESERVE_PAGES); + } + + return err; +} +EXPORT_SYMBOL_GPL(xs_swapper); +#endif + /** * cleanup_socket_xprt - remove xprtsock's sysctls, unregister * Index: linux-2.6/fs/Kconfig =================================================================== --- linux-2.6.orig/fs/Kconfig +++ linux-2.6/fs/Kconfig @@ -1690,6 +1690,18 @@ config NFS_DIRECTIO causes open() to return EINVAL if a file residing in NFS is opened with the O_DIRECT flag. +config NFS_SWAP + bool "Provide swap over NFS support" + default n + depends on NFS_FS + select SUNRPC_SWAP + help + This option enables swapon to work on files located on NFS mounts. + + For more details, see Documentation/vm_deadlock.txt + + If unsure, say N. + config NFSD tristate "NFS server support" depends on INET @@ -1824,6 +1836,12 @@ config SUNRPC_BIND34 If unsure, say N to get traditional behavior (version 2 rpcbind requests only). +config SUNRPC_SWAP + def_bool n + depends on SUNRPC + select NETVM + select SWAP_FILE + config RPCSEC_GSS_KRB5 tristate "Secure RPC: Kerberos V mechanism (EXPERIMENTAL)" depends on SUNRPC && EXPERIMENTAL -- - 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/