[07/14] aio-wait: Increase num_waiters even in home thread
diff mbox series

Message ID 20180907161520.26349-8-kwolf@redhat.com
State New
Headers show
Series
  • Fix some jobs/drain/aio_poll related hangs
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Commit Message

Kevin Wolf Sept. 7, 2018, 4:15 p.m. UTC
Even if AIO_WAIT_WHILE() is called in the home context of the
AioContext, we still want to allow the condition to change depending on
other threads as long as they kick the AioWait. Specfically block jobs
can be running in an I/O thread and should then be able to kick a drain
in the main loop context.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 include/block/aio-wait.h | 2 ++
 1 file changed, 2 insertions(+)

Comments

Fam Zheng Sept. 11, 2018, 8:25 a.m. UTC | #1
On Fri, 09/07 18:15, Kevin Wolf wrote:
> Even if AIO_WAIT_WHILE() is called in the home context of the
> AioContext, we still want to allow the condition to change depending on
> other threads as long as they kick the AioWait. Specfically block jobs
> can be running in an I/O thread and should then be able to kick a drain
> in the main loop context.

We can now move the atomic_inc/atomic_dec pair outside the if/else block,
but that's cosmetic.

Reviewed-by: Fam Zheng <famz@redhat.com>


> 
> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
> ---
>  include/block/aio-wait.h | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h
> index c85a62f798..46ba7f9111 100644
> --- a/include/block/aio-wait.h
> +++ b/include/block/aio-wait.h
> @@ -77,10 +77,12 @@ typedef struct {
>      AioWait *wait_ = (wait);                                       \
>      AioContext *ctx_ = (ctx);                                      \
>      if (ctx_ && in_aio_context_home_thread(ctx_)) {                \
> +        atomic_inc(&wait_->num_waiters);                           \
>          while ((cond)) {                                           \
>              aio_poll(ctx_, true);                                  \
>              waited_ = true;                                        \
>          }                                                          \
> +        atomic_dec(&wait_->num_waiters);                           \
>      } else {                                                       \
>          assert(qemu_get_current_aio_context() ==                   \
>                 qemu_get_aio_context());                            \
> -- 
> 2.13.6
>

Patch
diff mbox series

diff --git a/include/block/aio-wait.h b/include/block/aio-wait.h
index c85a62f798..46ba7f9111 100644
--- a/include/block/aio-wait.h
+++ b/include/block/aio-wait.h
@@ -77,10 +77,12 @@  typedef struct {
     AioWait *wait_ = (wait);                                       \
     AioContext *ctx_ = (ctx);                                      \
     if (ctx_ && in_aio_context_home_thread(ctx_)) {                \
+        atomic_inc(&wait_->num_waiters);                           \
         while ((cond)) {                                           \
             aio_poll(ctx_, true);                                  \
             waited_ = true;                                        \
         }                                                          \
+        atomic_dec(&wait_->num_waiters);                           \
     } else {                                                       \
         assert(qemu_get_current_aio_context() ==                   \
                qemu_get_aio_context());                            \