Provide an ops->swapfile() implementation for NFS. This will set the
NFS socket to SOCK_VMIO and run socket reconnect under PF_MEMALLOC as well
as reset SOCK_VMIO 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_VMIO 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 <[email protected]>
Cc: Trond Myklebust <[email protected]>
---
fs/Kconfig | 14 ++++++++++++
fs/nfs/file.c | 6 +++++
include/linux/sunrpc/xprt.h | 5 +++-
net/sunrpc/sched.c | 13 +++++++----
net/sunrpc/xprtsock.c | 49 ++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 81 insertions(+), 6 deletions(-)
Index: linux-2.6-git/fs/nfs/file.c
===================================================================
--- linux-2.6-git.orig/fs/nfs/file.c 2007-02-21 12:15:16.000000000 +0100
+++ linux-2.6-git/fs/nfs/file.c 2007-02-21 12:15:19.000000000 +0100
@@ -324,6 +324,11 @@ static int nfs_launder_page(struct page
return nfs_wb_page(page_file_mapping(page)->host, page);
}
+static int nfs_swapfile(struct address_space *mapping, int enable)
+{
+ return xs_swapper(NFS_CLIENT(mapping->host)->cl_xprt, enable);
+}
+
const struct address_space_operations nfs_file_aops = {
.readpage = nfs_readpage,
.readpages = nfs_readpages,
@@ -338,6 +343,7 @@ const struct address_space_operations nf
.direct_IO = nfs_direct_IO,
#endif
.launder_page = nfs_launder_page,
+ .swapfile = nfs_swapfile,
};
static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
Index: linux-2.6-git/include/linux/sunrpc/xprt.h
===================================================================
--- linux-2.6-git.orig/include/linux/sunrpc/xprt.h 2007-02-21 11:04:08.000000000 +0100
+++ linux-2.6-git/include/linux/sunrpc/xprt.h 2007-02-21 12:15:19.000000000 +0100
@@ -149,7 +149,9 @@ 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 */
/*
* Connection of transports
@@ -241,6 +243,7 @@ void xprt_disconnect(struct rpc_xprt *
*/
struct rpc_xprt * xs_setup_udp(struct sockaddr *addr, size_t addrlen, struct rpc_timeout *to);
struct rpc_xprt * xs_setup_tcp(struct sockaddr *addr, size_t addrlen, struct rpc_timeout *to);
+int xs_swapper(struct rpc_xprt *xprt, int enable);
/*
* Reserved bit positions in xprt->state
Index: linux-2.6-git/net/sunrpc/sched.c
===================================================================
--- linux-2.6-git.orig/net/sunrpc/sched.c 2007-02-21 11:04:08.000000000 +0100
+++ linux-2.6-git/net/sunrpc/sched.c 2007-02-21 12:15:19.000000000 +0100
@@ -751,10 +751,13 @@ void * rpc_malloc(struct rpc_task *task,
struct rpc_rqst *req = task->tk_rqstp;
gfp_t gfp;
- if (task->tk_flags & RPC_TASK_SWAPPER)
- gfp = GFP_ATOMIC;
- else
- gfp = GFP_NOFS;
+ /*
+ * this rcpio thread might be needed by reclaim, hence we cannot
+ * wait on a regular alloc to succeed.
+ */
+ gfp = GFP_ATOMIC;
+ if (RPC_IS_SWAPPER(task))
+ gfp |= __GFP_EMERGENCY;
if (size > RPC_BUFFER_MAXSIZE) {
req->rq_buffer = kmalloc(size, gfp);
@@ -834,7 +837,7 @@ 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-git/net/sunrpc/xprtsock.c
===================================================================
--- linux-2.6-git.orig/net/sunrpc/xprtsock.c 2007-02-21 11:04:08.000000000 +0100
+++ linux-2.6-git/net/sunrpc/xprtsock.c 2007-02-21 12:15:19.000000000 +0100
@@ -1215,11 +1215,15 @@ static void xs_udp_connect_worker(struct
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);
@@ -1257,6 +1261,9 @@ static void xs_udp_connect_worker(struct
transport->sock = sock;
transport->inet = sk;
+ if (xprt->swapper)
+ sk_set_vmio(sk);
+
write_unlock_bh(&sk->sk_callback_lock);
}
xs_udp_do_set_buffer_size(xprt);
@@ -1264,6 +1271,7 @@ static void xs_udp_connect_worker(struct
out:
xprt_wake_pending_tasks(xprt, status);
xprt_clear_connecting(xprt);
+ current->flags = pflags;
}
/*
@@ -1302,11 +1310,15 @@ static void xs_tcp_connect_worker(struct
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) {
@@ -1356,6 +1368,10 @@ static void xs_tcp_connect_worker(struct
write_unlock_bh(&sk->sk_callback_lock);
}
+
+ if (xprt->swapper)
+ sk_set_vmio(transport->inet);
+
/* Tell the socket layer to start connecting... */
xprt->stat.connect_count++;
xprt->stat.connect_start = jiffies;
@@ -1383,6 +1399,7 @@ out:
xprt_wake_pending_tasks(xprt, status);
out_clear:
xprt_clear_connecting(xprt);
+ current->flags = pflags;
}
/**
@@ -1642,6 +1659,38 @@ int init_socket_xprt(void)
return 0;
}
+#define RPC_BUF_RESERVE_PAGES (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.
+ */
+ sk_adjust_memalloc(1, RPC_RESERVE_PAGES);
+ sk_set_vmio(transport->inet);
+ xprt->swapper = 1;
+ } else if (xprt->swapper) {
+ xprt->swapper = 0;
+ sk_clear_vmio(transport->inet);
+ sk_adjust_memalloc(-1, -RPC_RESERVE_PAGES);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(xs_swapper);
+
/**
* cleanup_socket_xprt - remove xprtsock's sysctls
*
Index: linux-2.6-git/fs/Kconfig
===================================================================
--- linux-2.6-git.orig/fs/Kconfig 2007-02-21 11:04:08.000000000 +0100
+++ linux-2.6-git/fs/Kconfig 2007-02-21 12:15:19.000000000 +0100
@@ -1621,6 +1621,20 @@ 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 SLAB_FAIR
+ select NETVM
+ select SWAP_FILE
+ 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
--
-
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