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util/async: Add aio_co_reschedule_self()

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Add a function that can be used to move the currently running coroutine
to a different AioContext (and therefore potentially a different
thread).

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201005155855.256490-12-kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
This commit is contained in:
Kevin Wolf 2020-10-05 17:58:52 +02:00 committed by Markus Armbruster
parent bb4b9ead95
commit 26b0b698c0
2 changed files with 40 additions and 0 deletions
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10
include/block/aio.h
View file

@ -17,6 +17,7 @@
#ifdef CONFIG_LINUX_IO_URING
#include <liburing.h>
#endif
#include "qemu/coroutine.h"
#include "qemu/queue.h"
#include "qemu/event_notifier.h"
#include "qemu/thread.h"
@ -654,6 +655,15 @@ static inline bool aio_node_check(AioContext *ctx, bool is_external)
*/
void aio_co_schedule(AioContext *ctx, struct Coroutine *co);
/**
* aio_co_reschedule_self:
* @new_ctx: the new context
*
* Move the currently running coroutine to new_ctx. If the coroutine is already
* running in new_ctx, do nothing.
*/
void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx);
/**
* aio_co_wake:
* @co: the coroutine

30
util/async.c
View file

@ -569,6 +569,36 @@ void aio_co_schedule(AioContext *ctx, Coroutine *co)
aio_context_unref(ctx);
}
typedef struct AioCoRescheduleSelf {
Coroutine *co;
AioContext *new_ctx;
} AioCoRescheduleSelf;
static void aio_co_reschedule_self_bh(void *opaque)
{
AioCoRescheduleSelf *data = opaque;
aio_co_schedule(data->new_ctx, data->co);
}
void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx)
{
AioContext *old_ctx = qemu_get_current_aio_context();
if (old_ctx != new_ctx) {
AioCoRescheduleSelf data = {
.co = qemu_coroutine_self(),
.new_ctx = new_ctx,
};
/*
* We can't directly schedule the coroutine in the target context
* because this would be racy: The other thread could try to enter the
* coroutine before it has yielded in this one.
*/
aio_bh_schedule_oneshot(old_ctx, aio_co_reschedule_self_bh, &data);
qemu_coroutine_yield();
}
}
void aio_co_wake(struct Coroutine *co)
{
AioContext *ctx;