sched: Add a PF flag for ksoftirqd identification

Commit: 6cdd5199daf0cb7b0fcc8dca941af08492612887 upstream

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 <venki@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1286237003-12406-4-git-send-email-venki@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 32bf471f54795e0e1fb875d14ed9c997dabe724a..63d5aea2b9fd0a502b0437594eb70fa97530dea7 100644 (file)
--- 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 0ed83430b0773b97574747ab723601c6b4d8605d..0a617de2043463941c41b84f48bc26580a644e3b 100644 (file)
--- 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()) {