2011-02-10 12:28:32

by Venkatesh Pallipadi

[permalink] [raw]
Subject: [PATCH 16/28] sched: Add a PF flag for ksoftirqd identification

Commit: 6cdd5199daf0cb7b0fcc8dca941af08492612887 upstream
Author: Venkatesh Pallipadi <[email protected]>
AuthorDate: Mon Oct 4 17:03:18 2010 -0700

To account softirq time cleanly in scheduler, we need to identify whether
softirq is invoked in ksoftirqd context or softirq at hardirq tail context.
Add PF_KSOFTIRQD for that purpose.

As all PF flag bits are currently taken, create space by moving one of the
infrequently used bits (PF_THREAD_BOUND) down in task_struct to be along
with some other state fields.

Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Mike Galbraith <[email protected]>
Acked-by: Peter Zijlstra <[email protected]>
---
include/linux/sched.h | 1 +
kernel/softirq.c | 1 +
2 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 32bf471..63d5aea 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1728,6 +1728,7 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
/*
* Per process flags
*/
+#define PF_KSOFTIRQD 0x00000001 /* I am ksoftirqd */
#define PF_STARTING 0x00000002 /* being created */
#define PF_EXITING 0x00000004 /* getting shut down */
#define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 0ed8343..0a617de 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -718,6 +718,7 @@ static int ksoftirqd(void * __bind_cpu)
{
set_current_state(TASK_INTERRUPTIBLE);

+ current->flags |= PF_KSOFTIRQD;
while (!kthread_should_stop()) {
preempt_disable();
if (!local_softirq_pending()) {
--
1.7.4