[PATCH -mmotm 26/30] nfs: enable swap on NFS
in [Kernel]
|
Prev: [PATCH -mmotm 24/30] nfs: teach the NFS client how to treat PG_swapcache pages
Next: [PATCH -mmotm 14/30] net: sk_allocation() - concentrate socket related allocations
From: Xiaotian Feng on 13 Jul 2010 06:30 From 61388a8872071bb5b0015b9f5e3183410a98d949 Mon Sep 17 00:00:00 2001 From: Xiaotian Feng <dfeng(a)redhat.com> Date: Tue, 13 Jul 2010 13:11:13 +0800 Subject: [PATCH 26/30] nfs: enable swap on NFS Implement all the new swapfile a_ops 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 <a.p.zijlstra(a)chello.nl> Signed-off-by: Suresh Jayaraman <sjayaraman(a)suse.de> Signed-off-by: Xiaotian Feng <dfeng(a)redhat.com> --- fs/nfs/Kconfig | 10 ++++++ fs/nfs/file.c | 18 +++++++++++ fs/nfs/write.c | 22 ++++++++++++++ include/linux/nfs_fs.h | 2 + include/linux/sunrpc/xprt.h | 5 ++- mm/page_io.c | 1 + net/sunrpc/Kconfig | 5 +++ net/sunrpc/sched.c | 9 ++++- net/sunrpc/xprtsock.c | 68 +++++++++++++++++++++++++++++++++++++++++++ 9 files changed, 137 insertions(+), 3 deletions(-) diff --git a/fs/nfs/Kconfig b/fs/nfs/Kconfig index a43d07e..b022858 100644 --- a/fs/nfs/Kconfig +++ b/fs/nfs/Kconfig @@ -74,6 +74,16 @@ config NFS_V4 If unsure, say N. +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/network-swap.txt + config NFS_V4_1 bool "NFS client support for NFSv4.1 (DEVELOPER ONLY)" depends on NFS_V4 && EXPERIMENTAL diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 8f066fe..319c2b3 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -524,6 +524,18 @@ static int nfs_launder_page(struct page *page) return nfs_wb_page(inode, page); } +#ifdef CONFIG_NFS_SWAP +static int nfs_swapon(struct file *file) +{ + return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 1); +} + +static int nfs_swapoff(struct file *file) +{ + return xs_swapper(NFS_CLIENT(file->f_mapping->host)->cl_xprt, 0); +} +#endif + const struct address_space_operations nfs_file_aops = { .readpage = nfs_readpage, .readpages = nfs_readpages, @@ -538,6 +550,12 @@ const struct address_space_operations nfs_file_aops = { .migratepage = nfs_migrate_page, .launder_page = nfs_launder_page, .error_remove_page = generic_error_remove_page, +#ifdef CONFIG_NFS_SWAP + .swapon = nfs_swapon, + .swapoff = nfs_swapoff, + .swap_out = nfs_swap_out, + .swap_in = nfs_readpage, +#endif }; /* diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 0d7ea95..5852b20 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -355,6 +355,28 @@ int nfs_writepage(struct page *page, struct writeback_control *wbc) return ret; } +static int nfs_writepage_setup(struct nfs_open_context *ctx, struct page *page, + unsigned int offset, unsigned int count); + +int nfs_swap_out(struct file *file, struct page *page, + struct writeback_control *wbc) +{ + struct nfs_open_context *ctx = nfs_file_open_context(file); + int status; + + status = nfs_writepage_setup(ctx, page, 0, nfs_page_length(page)); + if (status < 0) { + nfs_set_pageerror(page); + goto out; + } + + status = nfs_writepage_locked(page, wbc); + +out: + unlock_page(page); + return status; +} + static int nfs_writepages_callback(struct page *page, struct writeback_control *wbc, void *data) { int ret; diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 77c2ae5..fc1bbfb 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -484,6 +484,8 @@ extern int nfs_writepages(struct address_space *, struct writeback_control *); extern int nfs_flush_incompatible(struct file *file, struct page *page); extern int nfs_updatepage(struct file *, struct page *, unsigned int, unsigned int); extern int nfs_writeback_done(struct rpc_task *, struct nfs_write_data *); +extern int nfs_swap_out(struct file *file, struct page *page, + struct writeback_control *wbc); /* * Try to write back everything synchronously (but check the diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index b514703..ba2330d 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -171,7 +171,9 @@ 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 */ /* @@ -303,6 +305,7 @@ void xprt_release_rqst_cong(struct rpc_task *task); void xprt_disconnect_done(struct rpc_xprt *xprt); void xprt_force_disconnect(struct rpc_xprt *xprt); void xprt_conditional_disconnect(struct rpc_xprt *xprt, unsigned int cookie); +int xs_swapper(struct rpc_xprt *xprt, int enable); /* * Reserved bit positions in xprt->state diff --git a/mm/page_io.c b/mm/page_io.c index 012b9ef..c8d7d8d 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -94,6 +94,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) { struct bio *bio; int ret = 0, rw = WRITE; + struct swap_info_struct *sis = page_swap_info(page); if (try_to_free_swap(page)) { unlock_page(page); diff --git a/net/sunrpc/Kconfig b/net/sunrpc/Kconfig index 443c161..521eadb 100644 --- a/net/sunrpc/Kconfig +++ b/net/sunrpc/Kconfig @@ -17,6 +17,11 @@ config SUNRPC_XPRT_RDMA If unsure, say N. +config SUNRPC_SWAP + def_bool n + depends on SUNRPC + select NETVM + config RPCSEC_GSS_KRB5 tristate "Secure RPC: Kerberos V mechanism (EXPERIMENTAL)" depends on SUNRPC && EXPERIMENTAL diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 4a843b8..6a16dc0 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -742,7 +742,10 @@ static void rpc_async_schedule(struct work_struct *work) 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) @@ -813,6 +816,8 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta kref_get(&task->tk_client->cl_kref); if (task->tk_client->cl_softrtry) task->tk_flags |= RPC_TASK_SOFT; + if (task->tk_client->cl_xprt->swapper) + task->tk_flags |= RPC_TASK_SWAPPER; } if (task->tk_ops->rpc_call_prepare != NULL) @@ -838,7 +843,7 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta 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); } /* diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 49a62f0..5c8b918 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1631,6 +1631,55 @@ static inline void xs_reclassify_socket6(struct socket *sock) } #endif +#ifdef CONFIG_SUNRPC_SWAP +static void xs_set_memalloc(struct rpc_xprt *xprt) +{ + struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt); + + if (xprt->swapper) + sk_set_memalloc(transport->inet); +} + +#define RPC_BUF_RESERVE_PAGES \ + kmalloc_estimate_objs(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) { + xprt->swapper = 1; + xs_set_memalloc(xprt); + } + } 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); +#else +static void xs_set_memalloc(struct rpc_xprt *xprt) +{ +} +#endif + static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock) { struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt); @@ -1655,6 +1704,8 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock) transport->sock = sock; transport->inet = sk; + xs_set_memalloc(xprt); + write_unlock_bh(&sk->sk_callback_lock); } xs_udp_do_set_buffer_size(xprt); @@ -1672,11 +1723,15 @@ static void xs_udp_connect_worker4(struct work_struct *work) 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) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + /* Start by resetting any existing state */ xs_reset_transport(transport); @@ -1703,6 +1758,7 @@ static void xs_udp_connect_worker4(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /** @@ -1717,11 +1773,15 @@ static void xs_udp_connect_worker6(struct work_struct *work) 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) goto out; + if (xprt->swapper) + current->flags |= PF_MEMALLOC; + /* Start by resetting any existing state */ xs_reset_transport(transport); @@ -1748,6 +1808,7 @@ static void xs_udp_connect_worker6(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } /* @@ -1822,6 +1883,8 @@ static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock) if (!xprt_bound(xprt)) return -ENOTCONN; + xs_set_memalloc(xprt); + /* Tell the socket layer to start connecting... */ xprt->stat.connect_count++; xprt->stat.connect_start = jiffies; @@ -1842,11 +1905,15 @@ static void xs_tcp_setup_socket(struct rpc_xprt *xprt, struct sock_xprt *)) { struct socket *sock = transport->sock; + 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 = create_sock(xprt, transport); @@ -1907,6 +1974,7 @@ out_eagain: out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + tsk_restore_flags(current, pflags, PF_MEMALLOC); } static struct socket *xs_create_tcp_sock4(struct rpc_xprt *xprt, -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |