| Message ID | 20180912171040.1732-4-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | aio-posix: polling mode bug fixes | expand |
On Wed, 09/12 19:10, Paolo Bonzini wrote: > Commit 70232b5253 ("aio-posix: Don't count ctx->notifier as progress when > 2018-08-15), by not reporting progress, causes aio_poll to execute the > system call when polling succeeds because of ctx->notifier. This introduces > latency before the call to aio_bh_poll() and negates the advantages of > polling, unfortunately. > > The fix builds on the previous patch, separating the effect of polling on > the timeout from the progress reported to aio_poll(). ctx->notifier > does zero the timeout, causing the caller to skip the system call, > but it does not report progress, so that the bug fix of commit 70232b5253 > still stands. > > Fixes: 70232b5253a3c4e03ed1ac47ef9246a8ac66c6fa > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > util/aio-posix.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/util/aio-posix.c b/util/aio-posix.c > index 21d8987179..efa79b9e62 100644 > --- a/util/aio-posix.c > +++ b/util/aio-posix.c > @@ -498,10 +498,11 @@ static bool run_poll_handlers_once(AioContext *ctx, int64_t *timeout) > QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { > if (!node->deleted && node->io_poll && > aio_node_check(ctx, node->is_external) && > - node->io_poll(node->opaque) && > - node->opaque != &ctx->notifier) { > + node->io_poll(node->opaque)) { > *timeout = 0; > - progress = true; > + if (node->opaque != &ctx->notifier) { > + progress = true; > + } > } > > /* Caller handles freeing deleted nodes. Don't do it here. */ > -- > 2.17.1 > Reviewed-by: Fam Zheng <famz@redhat.com>
diff --git a/util/aio-posix.c b/util/aio-posix.c index 21d8987179..efa79b9e62 100644 --- a/util/aio-posix.c +++ b/util/aio-posix.c @@ -498,10 +498,11 @@ static bool run_poll_handlers_once(AioContext *ctx, int64_t *timeout) QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) { if (!node->deleted && node->io_poll && aio_node_check(ctx, node->is_external) && - node->io_poll(node->opaque) && - node->opaque != &ctx->notifier) { + node->io_poll(node->opaque)) { *timeout = 0; - progress = true; + if (node->opaque != &ctx->notifier) { + progress = true; + } } /* Caller handles freeing deleted nodes. Don't do it here. */
Commit 70232b5253 ("aio-posix: Don't count ctx->notifier as progress when 2018-08-15), by not reporting progress, causes aio_poll to execute the system call when polling succeeds because of ctx->notifier. This introduces latency before the call to aio_bh_poll() and negates the advantages of polling, unfortunately. The fix builds on the previous patch, separating the effect of polling on the timeout from the progress reported to aio_poll(). ctx->notifier does zero the timeout, causing the caller to skip the system call, but it does not report progress, so that the bug fix of commit 70232b5253 still stands. Fixes: 70232b5253a3c4e03ed1ac47ef9246a8ac66c6fa Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- util/aio-posix.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)