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authorArjan van de Ven <arjan@linux.intel.com>2009-07-20 11:26:58 -0700
committerIngo Molnar <mingo@elte.hu>2009-09-02 08:44:08 +0200
commit8f0dfc34e9b323a028c2ec41abb7e9de477b7a94 (patch)
treefa7e44d9ad3eb22517f0724e71f9812f71a16ae2 /kernel/sched.c
parentf14eff1cc2f418a7c5e23aedc6a1bdca3343b871 (diff)
sched: Provide iowait counters
For counting how long an application has been waiting for (disk) IO, there currently is only the HZ sample driven information available, while for all other counters in this class, a high resolution version is available via CONFIG_SCHEDSTATS. In order to make an improved bootchart tool possible, we also need a higher resolution version of the iowait time. This patch below adds this scheduler statistic to the kernel. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4A64B813.1080506@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 6244d24cafc..38d05a89e0f 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6754,7 +6754,9 @@ void __sched io_schedule(void)
delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
+ current->in_iowait = 1;
schedule();
+ current->in_iowait = 0;
atomic_dec(&rq->nr_iowait);
delayacct_blkio_end();
}
@@ -6767,7 +6769,9 @@ long __sched io_schedule_timeout(long timeout)
delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
+ current->in_iowait = 1;
ret = schedule_timeout(timeout);
+ current->in_iowait = 0;
atomic_dec(&rq->nr_iowait);
delayacct_blkio_end();
return ret;