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From: Stefan Hajnoczi <stefanha@redhat.com>
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Subject: [Qemu-devel] [PULL 16/24] aio-posix: partially inline aio_dispatch
into aio_poll
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Cc: Peter Maydell <peter.maydell@linaro.org>,
Stefan Hajnoczi <stefanha@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
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From: Paolo Bonzini <pbonzini@redhat.com>
This patch prepares for the removal of unnecessary lockcnt inc/dec pairs.
Extract the dispatching loop for file descriptor handlers into a new
function aio_dispatch_handlers, and then inline aio_dispatch into
aio_poll.
aio_dispatch can now become void.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170213135235.12274-17-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
include/block/aio.h | 6 +-----
util/aio-posix.c | 44 ++++++++++++++------------------------------
util/aio-win32.c | 13 ++++---------
util/async.c | 2 +-
4 files changed, 20 insertions(+), 45 deletions(-)
diff --git a/include/block/aio.h b/include/block/aio.h
index 614cbc6..677b6ff 100644
--- a/include/block/aio.h
+++ b/include/block/aio.h
@@ -310,12 +310,8 @@ bool aio_pending(AioContext *ctx);
/* Dispatch any pending callbacks from the GSource attached to the AioCont=
ext.
*
* This is used internally in the implementation of the GSource.
- *
- * @dispatch_fds: true to process fds, false to skip them
- * (can be used as an optimization by callers that know the=
re
- * are no fds ready)
*/
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds);
+void aio_dispatch(AioContext *ctx);
=20
/* Progress in completing AIO work to occur. This can issue new pending
* aio as a result of executing I/O completion or bh callbacks.
diff --git a/util/aio-posix.c b/util/aio-posix.c
index 84cee43..2173378 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -386,12 +386,6 @@ static bool aio_dispatch_handlers(AioContext *ctx)
AioHandler *node, *tmp;
bool progress =3D false;
=20
- /*
- * We have to walk very carefully in case aio_set_fd_handler is
- * called while we're walking.
- */
- qemu_lockcnt_inc(&ctx->list_lock);
-
QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) {
int revents;
=20
@@ -426,33 +420,18 @@ static bool aio_dispatch_handlers(AioContext *ctx)
}
}
=20
- qemu_lockcnt_dec(&ctx->list_lock);
return progress;
}
=20
-/*
- * Note that dispatch_fds =3D=3D false has the side-effect of post-poning =
the
- * freeing of deleted handlers.
- */
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
+void aio_dispatch(AioContext *ctx)
{
- bool progress;
+ aio_bh_poll(ctx);
=20
- /*
- * If there are callbacks left that have been queued, we need to call =
them.
- * Do not call select in this case, because it is possible that the ca=
ller
- * does not need a complete flush (as is the case for aio_poll loops).
- */
- progress =3D aio_bh_poll(ctx);
+ qemu_lockcnt_inc(&ctx->list_lock);
+ aio_dispatch_handlers(ctx);
+ qemu_lockcnt_dec(&ctx->list_lock);
=20
- if (dispatch_fds) {
- progress |=3D aio_dispatch_handlers(ctx);
- }
-
- /* Run our timers */
- progress |=3D timerlistgroup_run_timers(&ctx->tlg);
-
- return progress;
+ timerlistgroup_run_timers(&ctx->tlg);
}
=20
/* These thread-local variables are used only in a small part of aio_poll
@@ -702,11 +681,16 @@ bool aio_poll(AioContext *ctx, bool blocking)
npfd =3D 0;
qemu_lockcnt_dec(&ctx->list_lock);
=20
- /* Run dispatch even if there were no readable fds to run timers */
- if (aio_dispatch(ctx, ret > 0)) {
- progress =3D true;
+ progress |=3D aio_bh_poll(ctx);
+
+ if (ret > 0) {
+ qemu_lockcnt_inc(&ctx->list_lock);
+ progress |=3D aio_dispatch_handlers(ctx);
+ qemu_lockcnt_dec(&ctx->list_lock);
}
=20
+ progress |=3D timerlistgroup_run_timers(&ctx->tlg);
+
return progress;
}
=20
diff --git a/util/aio-win32.c b/util/aio-win32.c
index 20b63ce..442a179 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -309,16 +309,11 @@ static bool aio_dispatch_handlers(AioContext *ctx, HA=
NDLE event)
return progress;
}
=20
-bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
+void aio_dispatch(AioContext *ctx)
{
- bool progress;
-
- progress =3D aio_bh_poll(ctx);
- if (dispatch_fds) {
- progress |=3D aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
- }
- progress |=3D timerlistgroup_run_timers(&ctx->tlg);
- return progress;
+ aio_bh_poll(ctx);
+ aio_dispatch_handlers(ctx, INVALID_HANDLE_VALUE);
+ timerlistgroup_run_timers(&ctx->tlg);
}
=20
bool aio_poll(AioContext *ctx, bool blocking)
diff --git a/util/async.c b/util/async.c
index c54da71..187bc5b 100644
--- a/util/async.c
+++ b/util/async.c
@@ -258,7 +258,7 @@ aio_ctx_dispatch(GSource *source,
AioContext *ctx =3D (AioContext *) source;
=20
assert(callback =3D=3D NULL);
- aio_dispatch(ctx, true);
+ aio_dispatch(ctx);
return true;
}
=20
--=20
2.9.3