Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e00ba3dae077f54cfd2af42e939a618caa7a3bca
Commit: e00ba3dae077f54cfd2af42e939a618caa7a3bca
Parent: e3c0ac04f980750a368f7cd5f1b8d1d2cdc1f735
Author: Jeff Moyer <[EMAIL PROTECTED]>
AuthorDate: Tue Dec 4 23:45:02 2007 -0800
Committer: Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Wed Dec 5 09:21:18 2007 -0800
aio: only account I/O wait time in read_events if there are active requests
On 2.6.24, top started showing 100% iowait on one CPU when a UML instance
was
running (but completely idle). The UML code sits in io_getevents waiting
for
an event to be submitted and completed.
Fix this by checking ctx->reqs_active before scheduling to determine whether
or not we are waiting for I/O.
Signed-off-by: Jeff Moyer <[EMAIL PROTECTED]>
Cc: Zach Brown <[EMAIL PROTECTED]>
Cc: Miklos Szeredi <[EMAIL PROTECTED]>
Cc: Jeff Dike <[EMAIL PROTECTED]>
Cc: "Rafael J. Wysocki" <[EMAIL PROTECTED]>
Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
---
fs/aio.c | 7 ++++++-
1 files changed, 6 insertions(+), 1 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index f12db41..9dec7d2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -1161,7 +1161,12 @@ retry:
ret = 0;
if (to.timed_out) /* Only check after read evt */
break;
- io_schedule();
+ /* Try to only show up in io wait if there are ops
+ * in flight */
+ if (ctx->reqs_active)
+ io_schedule();
+ else
+ schedule();
if (signal_pending(tsk)) {
ret = -EINTR;
break;
-
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