Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir.fraser@citrix.com>
# Date 1271770373 -3600
# Node ID dbf0fd95180f97bdf403ada605400723e4e8563d
# Parent b2c56f91da8d34e4daf4cceb1fc8a70a33656ae2
tasklet: Add lock-free exit path from do_tasklet() when no work to do.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>
---
xen/common/tasklet.c | 5 ++++-
1 files changed, 4 insertions(+), 1 deletion(-)

diff -r b2c56f91da8d -r dbf0fd95180f xen/common/tasklet.c
--- a/xen/common/tasklet.c Tue Apr 20 07:54:47 2010 +0100
+++ b/xen/common/tasklet.c Tue Apr 20 14:32:53 2010 +0100
@@ -60,9 +60,12 @@ void do_tasklet(void)
struct list_head *list = &per_cpu(tasklet_list, cpu);
struct tasklet *t;

+ if ( likely(list_empty(list)) )
+ return;
+
spin_lock_irq(&tasklet_lock);

- if ( list_empty(list) )
+ if ( unlikely(list_empty(list)) )
{
spin_unlock_irq(&tasklet_lock);
return;

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