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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Tue, 21 Feb 2017 11:56:31 +0000
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Subject: [Qemu-devel] [PULL v2 11/24] aio: push aio_context_acquire/release
down to dispatching
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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>
The AioContext data structures are now protected by list_lock and/or
they are walked with FOREACH_RCU primitives. There is no need anymore
to acquire the AioContext for the entire duration of aio_dispatch.
Instead, just acquire it before and after invoking the callbacks.
The next step is then to push it further down.
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: 20170213135235.12274-12-pbonzini@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
util/aio-posix.c | 25 +++++++++++--------------
util/aio-win32.c | 15 +++++++--------
util/async.c | 2 ++
3 files changed, 20 insertions(+), 22 deletions(-)
diff --git a/util/aio-posix.c b/util/aio-posix.c
index a8d7090..b590c5a 100644
--- a/util/aio-posix.c
+++ b/util/aio-posix.c
@@ -402,7 +402,9 @@ static bool aio_dispatch_handlers(AioContext *ctx)
(revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
aio_node_check(ctx, node->is_external) &&
node->io_read) {
+ aio_context_acquire(ctx);
node->io_read(node->opaque);
+ aio_context_release(ctx);
=20
/* aio_notify() does not count as progress */
if (node->opaque !=3D &ctx->notifier) {
@@ -413,7 +415,9 @@ static bool aio_dispatch_handlers(AioContext *ctx)
(revents & (G_IO_OUT | G_IO_ERR)) &&
aio_node_check(ctx, node->is_external) &&
node->io_write) {
+ aio_context_acquire(ctx);
node->io_write(node->opaque);
+ aio_context_release(ctx);
progress =3D true;
}
=20
@@ -450,7 +454,9 @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
}
=20
/* Run our timers */
+ aio_context_acquire(ctx);
progress |=3D timerlistgroup_run_timers(&ctx->tlg);
+ aio_context_release(ctx);
=20
return progress;
}
@@ -597,9 +603,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
int64_t timeout;
int64_t start =3D 0;
=20
- aio_context_acquire(ctx);
- progress =3D false;
-
/* aio_notify can avoid the expensive event_notifier_set if
* everything (file descriptors, bottom halves, timers) will
* be re-evaluated before the next blocking poll(). This is
@@ -617,9 +620,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
start =3D qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
=20
- if (try_poll_mode(ctx, blocking)) {
- progress =3D true;
- } else {
+ aio_context_acquire(ctx);
+ progress =3D try_poll_mode(ctx, blocking);
+ aio_context_release(ctx);
+
+ if (!progress) {
assert(npfd =3D=3D 0);
=20
/* fill pollfds */
@@ -636,9 +641,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
timeout =3D blocking ? aio_compute_timeout(ctx) : 0;
=20
/* wait until next event */
- if (timeout) {
- aio_context_release(ctx);
- }
if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
AioHandler epoll_handler;
=20
@@ -650,9 +652,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
} else {
ret =3D qemu_poll_ns(pollfds, npfd, timeout);
}
- if (timeout) {
- aio_context_acquire(ctx);
- }
}
=20
if (blocking) {
@@ -717,8 +716,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
progress =3D true;
}
=20
- aio_context_release(ctx);
-
return progress;
}
=20
diff --git a/util/aio-win32.c b/util/aio-win32.c
index 900524c..ab6d0e5 100644
--- a/util/aio-win32.c
+++ b/util/aio-win32.c
@@ -266,7 +266,9 @@ static bool aio_dispatch_handlers(AioContext *ctx, HAND=
LE event)
(revents || event_notifier_get_handle(node->e) =3D=3D event) &&
node->io_notify) {
node->pfd.revents =3D 0;
+ aio_context_acquire(ctx);
node->io_notify(node->e);
+ aio_context_release(ctx);
=20
/* aio_notify() does not count as progress */
if (node->e !=3D &ctx->notifier) {
@@ -278,11 +280,15 @@ static bool aio_dispatch_handlers(AioContext *ctx, HA=
NDLE event)
(node->io_read || node->io_write)) {
node->pfd.revents =3D 0;
if ((revents & G_IO_IN) && node->io_read) {
+ aio_context_acquire(ctx);
node->io_read(node->opaque);
+ aio_context_release(ctx);
progress =3D true;
}
if ((revents & G_IO_OUT) && node->io_write) {
+ aio_context_acquire(ctx);
node->io_write(node->opaque);
+ aio_context_release(ctx);
progress =3D true;
}
=20
@@ -329,7 +335,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
int count;
int timeout;
=20
- aio_context_acquire(ctx);
progress =3D false;
=20
/* aio_notify can avoid the expensive event_notifier_set if
@@ -371,17 +376,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
=20
timeout =3D blocking && !have_select_revents
? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
- if (timeout) {
- aio_context_release(ctx);
- }
ret =3D WaitForMultipleObjects(count, events, FALSE, timeout);
if (blocking) {
assert(first);
atomic_sub(&ctx->notify_me, 2);
}
- if (timeout) {
- aio_context_acquire(ctx);
- }
=20
if (first) {
aio_notify_accept(ctx);
@@ -404,8 +403,8 @@ bool aio_poll(AioContext *ctx, bool blocking)
progress |=3D aio_dispatch_handlers(ctx, event);
} while (count > 0);
=20
+ aio_context_acquire(ctx);
progress |=3D timerlistgroup_run_timers(&ctx->tlg);
-
aio_context_release(ctx);
return progress;
}
diff --git a/util/async.c b/util/async.c
index 9cac702..aec8016 100644
--- a/util/async.c
+++ b/util/async.c
@@ -114,7 +114,9 @@ int aio_bh_poll(AioContext *ctx)
ret =3D 1;
}
bh->idle =3D 0;
+ aio_context_acquire(ctx);
aio_bh_call(bh);
+ aio_context_release(ctx);
}
if (bh->deleted) {
deleted =3D true;
--=20
2.9.3