[PATCH 4/4] nfs: deadlock prevention for NFS
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 [EMAIL PROTECTED]
---
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 linux/slab.h
#include linux/pagemap.h
#include linux/smp_lock.h
+#include net/sock.h
#include asm/uaccess.h
#include asm/system.h
@@ -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 intmax_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
-
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Re: [PATCH 4/4] nfs: deadlock prevention for NFS
On Fri, 2006-08-25 at 16:14 -0400, Trond Myklebust wrote:
Grumble... If your patches are targetting NFS, could you please at the
very least Cc [EMAIL PROTECTED] and/or myself.
Sorry, will make sure you're on the CC list next round.
On Fri, 2006-08-25 at 17:40 +0200, Peter Zijlstra wrote:
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 [EMAIL PROTECTED]
---
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 linux/slab.h
#include linux/pagemap.h
#include linux/smp_lock.h
+#include net/sock.h
#include asm/uaccess.h
#include asm/system.h
@@ -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;
}
This all belongs in net/sunrpc/xprtsock.c. The NFS code has no business
screwing around with the internals of the sunrpc transport.
Ok, I'll make a function there, and call that.
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;
}
How does this guarantee that the socket reconnection won't fail?
I was afraid this might not be enough, I really have to go through the
network code.
Also, what about the case of rpc_malloc()? Can't that cause rpciod to
deadlock when you add NFS swap into the equation?
I will have to plead ignorance for now, I'll look into this on monday.
On first glance it looks like rpc_malloc could use an |__GFP_EMERG for
RPC_TASK_SWAPPER.
-
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Re: [PATCH 4/4] nfs: deadlock prevention for NFS
Grumble... If your patches are targetting NFS, could you please at the
very least Cc [EMAIL PROTECTED] and/or myself.
On Fri, 2006-08-25 at 17:40 +0200, Peter Zijlstra wrote:
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 [EMAIL PROTECTED]
---
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 linux/slab.h
#include linux/pagemap.h
#include linux/smp_lock.h
+#include net/sock.h
#include asm/uaccess.h
#include asm/system.h
@@ -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;
}
This all belongs in net/sunrpc/xprtsock.c. The NFS code has no business
screwing around with the internals of the sunrpc transport.
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;
}
How does this guarantee that the socket reconnection won't fail?
Also, what about the case of rpc_malloc()? Can't that cause rpciod to
deadlock when you add NFS swap into the equation?
Cheers,
Trond
-
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Re: [PATCH 4/4] nfs: deadlock prevention for NFS
/* Check if this were the first socks: */ if (nr_socks - socks == 0) reserve += RX_RESERVE_PAGES; Can of course be: if (nr_socks == socks) reserve += RX_RESERVE_PAGES; Grumble, Indan - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
