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authorJeff Layton <jlayton@poochiereds.net>2015-06-03 23:14:25 +0300
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-06-11 01:26:14 +0300
commit3c87ef6efb40f0e339d705c194b2224f854ec38e (patch)
tree2878ea261637cf6c85ab69b9cbde70a036b1e3a2 /include/linux/sunrpc
parent0d2a970d0ae55086520e1e58e572a7acd519429c (diff)
downloadlinux-3c87ef6efb40f0e339d705c194b2224f854ec38e.tar.xz
sunrpc: keep a count of swapfiles associated with the rpc_clnt
Jerome reported seeing a warning pop when working with a swapfile on NFS. The nfs_swap_activate can end up calling sk_set_memalloc while holding the rcu_read_lock and that function can sleep. To fix that, we need to take a reference to the xprt while holding the rcu_read_lock, set the socket up for swapping and then drop that reference. But, xprt_put is not exported and having NFS deal with the underlying xprt is a bit of layering violation anyway. Fix this by adding a set of activate/deactivate functions that take a rpc_clnt pointer instead of an rpc_xprt, and have nfs_swap_activate and nfs_swap_deactivate call those. Also, add a per-rpc_clnt atomic counter to keep track of the number of active swapfiles associated with it. When the counter does a 0->1 transition, we enable swapping on the xprt, when we do a 1->0 transition we disable swapping on it. This also allows us to be a bit more selective with the RPC_TASK_SWAPPER flag. If non-swapper and swapper clnts are sharing a xprt, then we only need to flag the tasks from the swapper clnt with that flag. Acked-by: Mel Gorman <mgorman@suse.de> Reported-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Reviewed-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'include/linux/sunrpc')
-rw-r--r--include/linux/sunrpc/clnt.h1
-rw-r--r--include/linux/sunrpc/sched.h16
2 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/sunrpc/clnt.h b/include/linux/sunrpc/clnt.h
index 598ba80ec30c..131032f15cc1 100644
--- a/include/linux/sunrpc/clnt.h
+++ b/include/linux/sunrpc/clnt.h
@@ -56,6 +56,7 @@ struct rpc_clnt {
struct rpc_rtt * cl_rtt; /* RTO estimator data */
const struct rpc_timeout *cl_timeout; /* Timeout strategy */
+ atomic_t cl_swapper; /* swapfile count */
int cl_nodelen; /* nodename length */
char cl_nodename[UNX_MAXNODENAME+1];
struct rpc_pipe_dir_head cl_pipedir_objects;
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 2aa68976a482..d703f0ef37d8 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -268,4 +268,20 @@ static inline void rpc_assign_waitqueue_name(struct rpc_wait_queue *q,
}
#endif
+#if IS_ENABLED(CONFIG_SUNRPC_SWAP)
+int rpc_clnt_swap_activate(struct rpc_clnt *clnt);
+void rpc_clnt_swap_deactivate(struct rpc_clnt *clnt);
+#else
+static inline int
+rpc_clnt_swap_activate(struct rpc_clnt *clnt)
+{
+ return -EINVAL;
+}
+
+static inline void
+rpc_clnt_swap_deactivate(struct rpc_clnt *clnt)
+{
+}
+#endif /* CONFIG_SUNRPC_SWAP */
+
#endif /* _LINUX_SUNRPC_SCHED_H_ */