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authorJeff Layton <jlayton@poochiereds.net>2015-03-20 20:15:14 +0100
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-04-23 20:38:07 +0200
commit5d05e54af3cdbb13cf19c557ff2184781b91a22c (patch)
treef67bf3bdb8ad1fd4cc61ec8d0e23dfafdcbd3f8b /fs/nfs/callback.c
parentNFS: Reduce time spent holding the i_mutex during fallocate() (diff)
downloadlinux-5d05e54af3cdbb13cf19c557ff2184781b91a22c.tar.xz
linux-5d05e54af3cdbb13cf19c557ff2184781b91a22c.zip
nfs: fix high load average due to callback thread sleeping
Chuck pointed out a problem that crept in with commit 6ffa30d3f734 (nfs: don't call blocking operations while !TASK_RUNNING). Linux counts tasks in uninterruptible sleep against the load average, so this caused the system's load average to be pinned at at least 1 when there was a NFSv4.1+ mount active. Not a huge problem, but it's probably worth fixing before we get too many complaints about it. This patch converts the code back to use TASK_INTERRUPTIBLE sleep, simply has it flush any signals on each loop iteration. In practice no one should really be signalling this thread at all, so I think this is reasonably safe. With this change, there's also no need to game the hung task watchdog so we can also convert the schedule_timeout call back to a normal schedule. Cc: <stable@vger.kernel.org> Reported-by: Chuck Lever <chuck.lever@oracle.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com> Tested-by: Chuck Lever <chuck.lever@oracle.com> Fixes: commit 6ffa30d3f734 (“nfs: don't call blocking . . .”) Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs/callback.c')
-rw-r--r--fs/nfs/callback.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 351be9205bf8..8d129bb7355a 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -128,7 +128,7 @@ nfs41_callback_svc(void *vrqstp)
if (try_to_freeze())
continue;
- prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_UNINTERRUPTIBLE);
+ prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_INTERRUPTIBLE);
spin_lock_bh(&serv->sv_cb_lock);
if (!list_empty(&serv->sv_cb_list)) {
req = list_first_entry(&serv->sv_cb_list,
@@ -142,10 +142,10 @@ nfs41_callback_svc(void *vrqstp)
error);
} else {
spin_unlock_bh(&serv->sv_cb_lock);
- /* schedule_timeout to game the hung task watchdog */
- schedule_timeout(60 * HZ);
+ schedule();
finish_wait(&serv->sv_cb_waitq, &wq);
}
+ flush_signals(current);
}
return 0;
}