3.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ilya Dryomov <[email protected]> commit 6d7fdb0ab351b33d4c12d53fe44be030b90fc9d4 upstream. This reverts commit 89baaa570ab0b476db09408d209578cfed700e9f. Dirty page throttling should be sufficient for us in the general case so there is no need to use __GFP_MEMALLOC - it would be needed only in the swap-over-rbd case, which we currently don't support. (It would probably take approximately the commit that is being reverted to add that support, but we would also need the "swap" option to distinguish from the general case and make sure swap ceph_client-s aren't shared with anything else.) See ceph-devel threads [1] and [2] for the details of why enabling pfmemalloc reserves for all cases is a bad thing. On top of potential system lockups related to drained emergency reserves, this turned out to cause ceph lockups in case peers are on the same host and communicating via loopback due to sk_filter() dropping pfmemalloc skbs on the receiving side because the receiving loopback socket is not tagged with SOCK_MEMALLOC. [1] "SOCK_MEMALLOC vs loopback" http://www.spinics.net/lists/ceph-devel/msg22998.html [2] "[PATCH] libceph: don't set memalloc flags in loopback case" http://www.spinics.net/lists/ceph-devel/msg23392.html Conflicts: net/ceph/messenger.c [ context: tcp_nodelay option ] Cc: Mike Christie <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Sage Weil <[email protected]> Signed-off-by: Ilya Dryomov <[email protected]> Acked-by: Mike Christie <[email protected]> Acked-by: Mel Gorman <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/ceph/messenger.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -484,7 +484,7 @@ static int ceph_tcp_connect(struct ceph_ IPPROTO_TCP, &sock); if (ret) return ret; - sock->sk->sk_allocation = GFP_NOFS | __GFP_MEMALLOC; + sock->sk->sk_allocation = GFP_NOFS; #ifdef CONFIG_LOCKDEP lockdep_set_class(&sock->sk->sk_lock, &socket_class); @@ -510,8 +510,6 @@ static int ceph_tcp_connect(struct ceph_ return ret; } - sk_set_memalloc(sock->sk); - con->sock = sock; return 0; } @@ -2798,11 +2796,8 @@ static void con_work(struct work_struct { struct ceph_connection *con = container_of(work, struct ceph_connection, work.work); - unsigned long pflags = current->flags; bool fault; - current->flags |= PF_MEMALLOC; - mutex_lock(&con->mutex); while (true) { int ret; @@ -2856,8 +2851,6 @@ static void con_work(struct work_struct con_fault_finish(con); con->ops->put(con); - - tsk_restore_flags(current, pflags, PF_MEMALLOC); } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
