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| author | Jeff Layton <jlayton@poochiereds.net> | 2015-03-20 15:15:14 -0400 |
|---|---|---|
| committer | Zefan Li <lizefan@huawei.com> | 2015-09-18 09:20:32 +0800 |
| commit | 20db578815361ac06fca1c03ef555324f00111d0 (patch) | |
| tree | dc6db94746a925528935d0767ecc011f50d40b4d | |
| parent | c9e5b3b7e731d070f5a95362281ea49718eb434d (diff) | |
| download | lwn-20db578815361ac06fca1c03ef555324f00111d0.tar.gz lwn-20db578815361ac06fca1c03ef555324f00111d0.zip | |
nfs: fix high load average due to callback thread sleeping
commit 5d05e54af3cdbb13cf19c557ff2184781b91a22c upstream.
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.
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>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>
| -rw-r--r-- | fs/nfs/callback.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c index 07c056c6a096..0184e91eb4fa 100644 --- a/fs/nfs/callback.c +++ b/fs/nfs/callback.c @@ -149,7 +149,7 @@ nfs41_callback_svc(void *vrqstp) set_freezable(); while (!kthread_should_stop()) { - 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, @@ -163,10 +163,10 @@ 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; } |