[PATCH] per-task-delay-accounting: sync block I/O and swapin delay collection

Unlike earlier iterations of the delay accounting patches, now delays are only
collected for the actual I/O waits rather than try and cover the delays seen
in I/O submission paths.

Account separately for block I/O delays incurred as a result of swapin page
faults whose frequency can be affected by the task/process' rss limit.  Hence
swapin delays can act as feedback for rss limit changes independent of I/O
priority changes.

Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7a54e62763c5..2f43f1fb7de7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -566,6 +566,19 @@ struct task_delay_info {
          * Atomicity of updates to XXX_delay, XXX_count protected by
          * single lock above (split into XXX_lock if contention is an issue).
          */
+
+        /*
+         * XXX_count is incremented on every XXX operation, the delay
+         * associated with the operation is added to XXX_delay.
+         * XXX_delay contains the accumulated delay time in nanoseconds.
+         */
+        struct timespec blkio_start, blkio_end; /* Shared by blkio, swapin */
+        u64 blkio_delay;        /* wait for sync block io completion */
+        u64 swapin_delay;       /* wait for swapin block io completion */
+        u32 blkio_count;        /* total count of the number of sync block */
+                                /* io operations performed */
+        u32 swapin_count;       /* total count of the number of swapin block */
+                                /* io operations performed */
 };
 #endif