queue-2.6.22.y/KAIO-aio-account_IO-wait-time-properly.patch

   1 From 41d10da3717409de33d5441f2f6d8f072ab3fbb6 Mon Sep 17 00:00:00 2001
   2 From: Jeff Moyer <jmoyer@redhat.com>
   3 Date: Tue, 16 Oct 2007 23:27:20 -0700
   4 Subject: [PATCH] aio: account I/O wait time properly
   5
   6 Some months back I proposed changing the schedule() call in
   7 read_events to an io_schedule():
   8         http://osdir.com/ml/linux.kernel.aio.general/2006-10/msg00024.html
   9 This was rejected as there are AIO operations that do not initiate
  10 disk I/O.  I've had another look at the problem, and the only AIO
  11 operation that will not initiate disk I/O is IOCB_CMD_NOOP.  However,
  12 this command isn't even wired up!
  13
  14 Given that it doesn't work, and hasn't for *years*, I'm going to
  15 suggest again that we do proper I/O accounting when using AIO.
  16
  17 Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
  18 Acked-by: Zach Brown <zach.brown@oracle.com>
  19 Cc: Benjamin LaHaise <bcrl@kvack.org>
  20 Cc: Suparna Bhattacharya <suparna@in.ibm.com>
  21 Cc: Badari Pulavarty <pbadari@us.ibm.com>
  22 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  23 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  24
  25 diff --git a/fs/aio.c b/fs/aio.c
  26 index ea2e198..d02f43b 100644
  27 --- a/fs/aio.c
  28 +++ b/fs/aio.c
  29 @@ -303,7 +303,7 @@ static void wait_for_all_aios(struct kioctx *ctx)
  30         set_task_state(tsk, TASK_UNINTERRUPTIBLE);
  31         while (ctx->reqs_active) {
  32                 spin_unlock_irq(&ctx->ctx_lock);
  33 -               schedule();
  34 +               io_schedule();
  35                 set_task_state(tsk, TASK_UNINTERRUPTIBLE);
  36                 spin_lock_irq(&ctx->ctx_lock);
  37         }
  38 @@ -323,7 +323,7 @@ ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb)
  39                 set_current_state(TASK_UNINTERRUPTIBLE);
  40                 if (!iocb->ki_users)
  41                         break;
  42 -               schedule();
  43 +               io_schedule();
  44         }
  45         __set_current_state(TASK_RUNNING);
  46         return iocb->ki_user_data;
  47 @@ -1170,7 +1170,7 @@ retry:
  48                         ret = 0;
  49                         if (to.timed_out)       /* Only check after read evt */
  50                                 break;
  51 -                       schedule();
  52 +                       io_schedule();
  53                         if (signal_pending(tsk)) {
  54                                 ret = -EINTR;
  55                                 break;