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[Qemu-devel] [PATCH 09/16] aio: push aio_context_acquire/release down to
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 09/16] aio: push aio_context_acquire/release down to dispatching |
Date: |
Fri, 13 Jan 2017 14:17:24 +0100 |
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 <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
aio-posix.c | 25 +++++++++++--------------
aio-win32.c | 15 +++++++--------
async.c | 2 ++
3 files changed, 20 insertions(+), 22 deletions(-)
diff --git a/aio-posix.c b/aio-posix.c
index 9453d83..3fd64fb 100644
--- a/aio-posix.c
+++ b/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);
/* aio_notify() does not count as progress */
if (node->opaque != &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 = true;
}
@@ -450,7 +454,9 @@ bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
}
/* Run our timers */
+ aio_context_acquire(ctx);
progress |= timerlistgroup_run_timers(&ctx->tlg);
+ aio_context_release(ctx);
return progress;
}
@@ -596,9 +602,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
int64_t timeout;
int64_t start = 0;
- aio_context_acquire(ctx);
- progress = 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
@@ -616,9 +619,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
}
- if (try_poll_mode(ctx, blocking)) {
- progress = true;
- } else {
+ aio_context_acquire(ctx);
+ progress = try_poll_mode(ctx, blocking);
+ aio_context_release(ctx);
+
+ if (!progress) {
assert(npfd == 0);
/* fill pollfds */
@@ -635,9 +640,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
timeout = blocking ? aio_compute_timeout(ctx) : 0;
/* wait until next event */
- if (timeout) {
- aio_context_release(ctx);
- }
if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
AioHandler epoll_handler;
@@ -649,9 +651,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
} else {
ret = qemu_poll_ns(pollfds, npfd, timeout);
}
- if (timeout) {
- aio_context_acquire(ctx);
- }
}
if (blocking) {
@@ -716,8 +715,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
progress = true;
}
- aio_context_release(ctx);
-
return progress;
}
diff --git a/aio-win32.c b/aio-win32.c
index 900524c..ab6d0e5 100644
--- a/aio-win32.c
+++ b/aio-win32.c
@@ -266,7 +266,9 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE
event)
(revents || event_notifier_get_handle(node->e) == event) &&
node->io_notify) {
node->pfd.revents = 0;
+ aio_context_acquire(ctx);
node->io_notify(node->e);
+ aio_context_release(ctx);
/* aio_notify() does not count as progress */
if (node->e != &ctx->notifier) {
@@ -278,11 +280,15 @@ static bool aio_dispatch_handlers(AioContext *ctx, HANDLE
event)
(node->io_read || node->io_write)) {
node->pfd.revents = 0;
if ((revents & G_IO_IN) && node->io_read) {
+ aio_context_acquire(ctx);
node->io_read(node->opaque);
+ aio_context_release(ctx);
progress = true;
}
if ((revents & G_IO_OUT) && node->io_write) {
+ aio_context_acquire(ctx);
node->io_write(node->opaque);
+ aio_context_release(ctx);
progress = true;
}
@@ -329,7 +335,6 @@ bool aio_poll(AioContext *ctx, bool blocking)
int count;
int timeout;
- aio_context_acquire(ctx);
progress = false;
/* aio_notify can avoid the expensive event_notifier_set if
@@ -371,17 +376,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
timeout = blocking && !have_select_revents
? qemu_timeout_ns_to_ms(aio_compute_timeout(ctx)) : 0;
- if (timeout) {
- aio_context_release(ctx);
- }
ret = WaitForMultipleObjects(count, events, FALSE, timeout);
if (blocking) {
assert(first);
atomic_sub(&ctx->notify_me, 2);
}
- if (timeout) {
- aio_context_acquire(ctx);
- }
if (first) {
aio_notify_accept(ctx);
@@ -404,8 +403,8 @@ bool aio_poll(AioContext *ctx, bool blocking)
progress |= aio_dispatch_handlers(ctx, event);
} while (count > 0);
+ aio_context_acquire(ctx);
progress |= timerlistgroup_run_timers(&ctx->tlg);
-
aio_context_release(ctx);
return progress;
}
diff --git a/async.c b/async.c
index 1338682..ccb70e7 100644
--- a/async.c
+++ b/async.c
@@ -113,7 +113,9 @@ int aio_bh_poll(AioContext *ctx)
ret = 1;
}
bh->idle = 0;
+ aio_context_acquire(ctx);
aio_bh_call(bh);
+ aio_context_release(ctx);
}
if (bh->deleted) {
deleted = true;
--
2.9.3
- Re: [Qemu-devel] [PATCH 01/16] aio: introduce aio_co_schedule and aio_co_wake, (continued)
Re: [Qemu-devel] [PATCH 01/16] aio: introduce aio_co_schedule and aio_co_wake, Stefan Hajnoczi, 2017/01/18
[Qemu-devel] [PATCH 06/16] nbd: do not block on partial reply header reads, Paolo Bonzini, 2017/01/13
[Qemu-devel] [PATCH 08/16] qed: introduce qed_aio_start_io and qed_aio_next_io_cb, Paolo Bonzini, 2017/01/13
[Qemu-devel] [PATCH 09/16] aio: push aio_context_acquire/release down to dispatching,
Paolo Bonzini <=
[Qemu-devel] [PATCH 15/16] async: remove unnecessary inc/dec pairs, Paolo Bonzini, 2017/01/13
[Qemu-devel] [PATCH 13/16] block: explicitly acquire aiocontext in aio callbacks that need it, Paolo Bonzini, 2017/01/13
[Qemu-devel] [PATCH 16/16] block: document fields protected by AioContext lock, Paolo Bonzini, 2017/01/13
[Qemu-devel] [PATCH 10/16] block: explicitly acquire aiocontext in timers that need it, Paolo Bonzini, 2017/01/13