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authorDai Ngo <dai.ngo@oracle.com>2024-01-30 11:38:25 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-04-13 12:59:48 +0200
commit4b676584d02e4c3d620196b26039063adeb0800c (patch)
tree0e7748132380760fe502d478d7984d4dc8067418
parent0b5668a87caa6e5a98c78168fb0d9f02f6b7794f (diff)
downloadchromeos-4b676584d02e4c3d620196b26039063adeb0800c.tar.gz
SUNRPC: increase size of rpc_wait_queue.qlen from unsigned short to unsigned int
[ Upstream commit 2c35f43b5a4b9cdfaa6fdd946f5a212615dac8eb ] When the NFS client is under extreme load the rpc_wait_queue.qlen counter can be overflowed. Here is an instant of the backlog queue overflow in a real world environment shown by drgn helper: rpc_task_stats(rpc_clnt): ------------------------- rpc_clnt: 0xffff92b65d2bae00 rpc_xprt: 0xffff9275db64f000 Queue: sending[64887] pending[524] backlog[30441] binding[0] XMIT task: 0xffff925c6b1d8e98 WRITE: 750654 __dta_call_status_580: 65463 __dta_call_transmit_status_579: 1 call_reserveresult: 685189 nfs_client_init_is_complete: 1 COMMIT: 584 call_reserveresult: 573 __dta_call_status_580: 11 ACCESS: 1 __dta_call_status_580: 1 GETATTR: 10 __dta_call_status_580: 4 call_reserveresult: 6 751249 tasks for server 111.222.333.444 Total tasks: 751249 count_rpc_wait_queues(xprt): ---------------------------- **** rpc_xprt: 0xffff9275db64f000 num_reqs: 65511 wait_queue: xprt_binding[0] cnt: 0 wait_queue: xprt_binding[1] cnt: 0 wait_queue: xprt_binding[2] cnt: 0 wait_queue: xprt_binding[3] cnt: 0 rpc_wait_queue[xprt_binding].qlen: 0 maxpriority: 0 wait_queue: xprt_sending[0] cnt: 0 wait_queue: xprt_sending[1] cnt: 64887 wait_queue: xprt_sending[2] cnt: 0 wait_queue: xprt_sending[3] cnt: 0 rpc_wait_queue[xprt_sending].qlen: 64887 maxpriority: 3 wait_queue: xprt_pending[0] cnt: 524 wait_queue: xprt_pending[1] cnt: 0 wait_queue: xprt_pending[2] cnt: 0 wait_queue: xprt_pending[3] cnt: 0 rpc_wait_queue[xprt_pending].qlen: 524 maxpriority: 0 wait_queue: xprt_backlog[0] cnt: 0 wait_queue: xprt_backlog[1] cnt: 685801 wait_queue: xprt_backlog[2] cnt: 0 wait_queue: xprt_backlog[3] cnt: 0 rpc_wait_queue[xprt_backlog].qlen: 30441 maxpriority: 3 [task cnt mismatch] There is no effect on operations when this overflow occurs. However it causes confusion when trying to diagnose the performance problem. Signed-off-by: Dai Ngo <dai.ngo@oracle.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--include/linux/sunrpc/sched.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 256dff36cf7207..0527a4bc9a36f4 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -197,7 +197,7 @@ struct rpc_wait_queue {
unsigned char maxpriority; /* maximum priority (0 if queue is not a priority queue) */
unsigned char priority; /* current priority */
unsigned char nr; /* # tasks remaining for cookie */
- unsigned short qlen; /* total # tasks waiting in queue */
+ unsigned int qlen; /* total # tasks waiting in queue */
struct rpc_timer timer_list;
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG) || IS_ENABLED(CONFIG_TRACEPOINTS)
const char * name;