From bde6c3aa993066acb0d6ce32ecabe03b9d5df92d Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Tue, 1 Jul 2014 11:26:57 -0700
Subject: rcu: Provide cond_resched_rcu_qs() to force quiescent states in long
loops
RCU-tasks requires the occasional voluntary context switch
from CPU-bound in-kernel tasks. In some cases, this requires
instrumenting cond_resched(). However, there is some reluctance
to countenance unconditionally instrumenting cond_resched() (see
http://lwn.net/Articles/603252/), so this commit creates a separate
cond_resched_rcu_qs() that may be used in place of cond_resched() in
locations prone to long-duration in-kernel looping.
This commit currently instruments only RCU-tasks. Future possibilities
include also instrumenting RCU, RCU-bh, and RCU-sched in order to reduce
IPI usage.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
fs/file.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
(limited to 'fs/file.c')
diff --git a/fs/file.c b/fs/file.c
index 66923fe3176..1cafc4c9275 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -367,7 +367,7 @@ static struct fdtable *close_files(struct files_struct * files)
struct file * file = xchg(&fdt->fd[i], NULL);
if (file) {
filp_close(file, files);
- cond_resched();
+ cond_resched_rcu_qs();
}
}
i++;
--
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