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authorMel Gorman <mgorman@suse.de>2012-07-31 23:44:32 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2012-08-01 01:42:46 (GMT)
commit7f338fe4540b1d0600b02314c7d885fd358e9eca (patch)
treedbd0fe3c3d874ae622980dae4b15605bb9e2052a /drivers
parent381760eadc393bcb1bb328510ad75cf13431806d (diff)
downloadlinux-7f338fe4540b1d0600b02314c7d885fd358e9eca.tar.xz
nbd: set SOCK_MEMALLOC for access to PFMEMALLOC reserves
Set SOCK_MEMALLOC on the NBD socket to allow access to PFMEMALLOC reserves so pages backed by NBD, particularly if swap related, can be cleaned to prevent the machine being deadlocked. It is still possible that the PFMEMALLOC reserves get depleted resulting in deadlock but this can be resolved by the administrator by increasing min_free_kbytes. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/nbd.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 061427a..76bc96f 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -154,6 +154,7 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
struct msghdr msg;
struct kvec iov;
sigset_t blocked, oldset;
+ unsigned long pflags = current->flags;
if (unlikely(!sock)) {
dev_err(disk_to_dev(nbd->disk),
@@ -167,8 +168,9 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
siginitsetinv(&blocked, sigmask(SIGKILL));
sigprocmask(SIG_SETMASK, &blocked, &oldset);
+ current->flags |= PF_MEMALLOC;
do {
- sock->sk->sk_allocation = GFP_NOIO;
+ sock->sk->sk_allocation = GFP_NOIO | __GFP_MEMALLOC;
iov.iov_base = buf;
iov.iov_len = size;
msg.msg_name = NULL;
@@ -214,6 +216,7 @@ static int sock_xmit(struct nbd_device *nbd, int send, void *buf, int size,
} while (size > 0);
sigprocmask(SIG_SETMASK, &oldset, NULL);
+ tsk_restore_flags(current, pflags, PF_MEMALLOC);
return result;
}
@@ -405,6 +408,7 @@ static int nbd_do_it(struct nbd_device *nbd)
BUG_ON(nbd->magic != NBD_MAGIC);
+ sk_set_memalloc(nbd->sock->sk);
nbd->pid = task_pid_nr(current);
ret = device_create_file(disk_to_dev(nbd->disk), &pid_attr);
if (ret) {