Changelog
Fixes comments by akpm (on earlier patch now incorporated here)
- detailed comments on atomicity rules of accounting fields
- replace use of nsec_t
delayacct-taskstats.patch
Usage of taskstats interface by delay accounting.
Signed-off-by: Shailabh Nagar <[email protected]>
Signed-off-by: Balbir Singh <[email protected]>
include/linux/delayacct.h | 11 ++++++++++
include/linux/taskstats.h | 48 +++++++++++++++++++++++++++++++++++++++++++++-
init/Kconfig | 1
kernel/delayacct.c | 42 ++++++++++++++++++++++++++++++++++++++++
kernel/taskstats.c | 9 +++++++-
5 files changed, 109 insertions(+), 2 deletions(-)
Index: linux-2.6.17-rc1/include/linux/delayacct.h
===================================================================
--- linux-2.6.17-rc1.orig/include/linux/delayacct.h 2006-04-21 20:29:13.000000000 -0400
+++ linux-2.6.17-rc1/include/linux/delayacct.h 2006-04-21 20:42:41.000000000 -0400
@@ -18,6 +18,7 @@
#define _LINUX_TASKDELAYS_H
#include <linux/sched.h>
+#include <linux/taskstats_kern.h>
/*
* Per-task flags relevant to delay accounting
@@ -35,6 +36,7 @@ extern void __delayacct_tsk_init(struct
extern void __delayacct_tsk_exit(struct task_struct *);
extern void __delayacct_blkio_start(void);
extern void __delayacct_blkio_end(void);
+extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
static inline void delayacct_set_flag(int flag)
{
@@ -74,6 +76,13 @@ static inline void delayacct_blkio_end(v
__delayacct_blkio_end();
}
+static inline int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+{
+ if (!tsk->delays)
+ return -EINVAL;
+ return __delayacct_add_tsk(d, tsk);
+}
+
#else
static inline void delayacct_set_flag(int flag)
{}
@@ -89,6 +98,8 @@ static inline void delayacct_blkio_start
{}
static inline void delayacct_blkio_end(void)
{}
+static inline int delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+{ return 0; }
#endif /* CONFIG_TASK_DELAY_ACCT */
#endif
Index: linux-2.6.17-rc1/kernel/delayacct.c
===================================================================
--- linux-2.6.17-rc1.orig/kernel/delayacct.c 2006-04-21 20:29:13.000000000 -0400
+++ linux-2.6.17-rc1/kernel/delayacct.c 2006-04-21 20:40:03.000000000 -0400
@@ -104,3 +104,45 @@ void __delayacct_blkio_end(void)
¤t->delays->blkio_delay,
¤t->delays->blkio_count);
}
+
+int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
+{
+ s64 tmp;
+ struct timespec ts;
+ unsigned long t1,t2,t3;
+
+
+ tmp = (s64)d->cpu_run_real_total;
+ tmp += (u64)(tsk->utime + tsk->stime) * TICK_NSEC;
+ d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp;
+
+ /* No locking available for sched_info (and too expensive to add one)
+ * Mitigate by taking snapshot of values
+ */
+ t1 = tsk->sched_info.pcnt;
+ t2 = tsk->sched_info.run_delay;
+ t3 = tsk->sched_info.cpu_time;
+
+ d->cpu_count += t1;
+
+ jiffies_to_timespec(t2, &ts);
+ tmp = (s64)d->cpu_delay_total + timespec_to_ns(&ts);
+ d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp;
+
+ tmp = (s64)d->cpu_run_virtual_total + (s64)jiffies_to_usecs(t3) * 1000;
+ d->cpu_run_virtual_total =
+ (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp;
+
+ /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */
+
+ spin_lock(&tsk->delays->lock);
+ tmp = d->blkio_delay_total + tsk->delays->blkio_delay;
+ d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
+ tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
+ d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
+ d->blkio_count += tsk->delays->blkio_count;
+ d->swapin_count += tsk->delays->swapin_count;
+ spin_unlock(&tsk->delays->lock);
+
+ return 0;
+}
Index: linux-2.6.17-rc1/kernel/taskstats.c
===================================================================
--- linux-2.6.17-rc1.orig/kernel/taskstats.c 2006-04-21 20:29:22.000000000 -0400
+++ linux-2.6.17-rc1/kernel/taskstats.c 2006-04-21 20:40:03.000000000 -0400
@@ -18,6 +18,7 @@
#include <linux/kernel.h>
#include <linux/taskstats_kern.h>
+#include <linux/delayacct.h>
#include <net/genetlink.h>
#include <asm/atomic.h>
@@ -119,7 +120,9 @@ static int fill_pid(pid_t pid, struct ta
* goto err;
*/
-err:
+ rc = delayacct_add_tsk(stats, tsk);
+
+ /* Define err: label here if needed */
put_task_struct(tsk);
return rc;
@@ -151,6 +154,10 @@ static int fill_tgid(pid_t tgid, struct
* break;
*/
+ rc = delayacct_add_tsk(stats, tsk);
+ if (rc)
+ break;
+
} while_each_thread(first, tsk);
read_unlock(&tasklist_lock);
Index: linux-2.6.17-rc1/init/Kconfig
===================================================================
--- linux-2.6.17-rc1.orig/init/Kconfig 2006-04-21 20:29:22.000000000 -0400
+++ linux-2.6.17-rc1/init/Kconfig 2006-04-21 20:40:03.000000000 -0400
@@ -164,6 +164,7 @@ config TASKSTATS
config TASK_DELAY_ACCT
bool "Enable per-task delay accounting (EXPERIMENTAL)"
+ depends on TASKSTATS
help
Collect information on time spent by a task waiting for system
resources like cpu, synchronous block I/O completion and swapping
Index: linux-2.6.17-rc1/include/linux/taskstats.h
===================================================================
--- linux-2.6.17-rc1.orig/include/linux/taskstats.h 2006-04-21 20:31:11.000000000 -0400
+++ linux-2.6.17-rc1/include/linux/taskstats.h 2006-04-21 20:45:17.000000000 -0400
@@ -35,7 +35,53 @@ struct taskstats {
/* Version 1 */
- int filler_avoids_empty_struct_warnings;
+ /* Delay accounting fields start
+ *
+ * All values, until comment "Delay accounting fields end" are
+ * available only if delay accounting is enabled, even though the last
+ * few fields are not delays
+ *
+ * xxx_count is the number of delay values recorded
+ * xxx_delay_total is the corresponding cumulative delay in nanoseconds
+ *
+ * xxx_delay_total wraps around to zero on overflow
+ * xxx_count incremented regardless of overflow
+ */
+
+ /* Delay waiting for cpu, while runnable
+ * count, delay_total NOT updated atomically
+ */
+ __u64 cpu_count;
+ __u64 cpu_delay_total;
+
+ /* Following four fields atomically updated using task->delays->lock */
+
+ /* Delay waiting for synchronous block I/O to complete
+ * does not account for delays in I/O submission
+ */
+ __u64 blkio_count;
+ __u64 blkio_delay_total;
+
+ /* Delay waiting for page fault I/O (swap in only) */
+ __u64 swapin_count;
+ __u64 swapin_delay_total;
+
+ /* cpu "wall-clock" running time
+ * On some architectures, value will adjust for cpu time stolen
+ * from the kernel in involuntary waits due to virtualization.
+ * Value is cumulative, in nanoseconds, without a corresponding count
+ * and wraps around to zero silently on overflow
+ */
+ __u64 cpu_run_real_total;
+
+ /* cpu "virtual" running time
+ * Uses time intervals seen by the kernel i.e. no adjustment
+ * for kernel's involuntary waits due to virtualization.
+ * Value is cumulative, in nanoseconds, without a corresponding count
+ * and wraps around to zero silently on overflow
+ */
+ __u64 cpu_run_virtual_total;
+ /* Delay accounting fields end */
};
-
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