87 lines
2.5 KiB
Diff
87 lines
2.5 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Wed, 27 May 2020 11:33:20 +0200
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Subject: [PATCH] util/async: Add aio_co_reschedule_self()
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From: Kevin Wolf <kwolf@redhat.com>
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Add a function that can be used to move the currently running coroutine
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to a different AioContext (and therefore potentially a different
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thread).
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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include/block/aio.h | 10 ++++++++++
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util/async.c | 30 ++++++++++++++++++++++++++++++
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2 files changed, 40 insertions(+)
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diff --git a/include/block/aio.h b/include/block/aio.h
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index 62ed954344..d5399c67d6 100644
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--- a/include/block/aio.h
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+++ b/include/block/aio.h
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@@ -17,6 +17,7 @@
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#ifdef CONFIG_LINUX_IO_URING
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#include <liburing.h>
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#endif
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+#include "qemu/coroutine.h"
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#include "qemu/queue.h"
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#include "qemu/event_notifier.h"
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#include "qemu/thread.h"
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@@ -654,6 +655,15 @@ static inline bool aio_node_check(AioContext *ctx, bool is_external)
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*/
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void aio_co_schedule(AioContext *ctx, struct Coroutine *co);
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+/**
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+ * aio_co_reschedule_self:
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+ * @new_ctx: the new context
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+ *
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+ * Move the currently running coroutine to new_ctx. If the coroutine is already
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+ * running in new_ctx, do nothing.
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+ */
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+void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx);
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+
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/**
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* aio_co_wake:
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* @co: the coroutine
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diff --git a/util/async.c b/util/async.c
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index 3165a28f2f..4eba1e6f1b 100644
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--- a/util/async.c
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+++ b/util/async.c
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@@ -558,6 +558,36 @@ void aio_co_schedule(AioContext *ctx, Coroutine *co)
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aio_context_unref(ctx);
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}
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+typedef struct AioCoRescheduleSelf {
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+ Coroutine *co;
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+ AioContext *new_ctx;
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+} AioCoRescheduleSelf;
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+
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+static void aio_co_reschedule_self_bh(void *opaque)
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+{
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+ AioCoRescheduleSelf *data = opaque;
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+ aio_co_schedule(data->new_ctx, data->co);
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+}
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+
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+void coroutine_fn aio_co_reschedule_self(AioContext *new_ctx)
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+{
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+ AioContext *old_ctx = qemu_get_current_aio_context();
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+
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+ if (old_ctx != new_ctx) {
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+ AioCoRescheduleSelf data = {
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+ .co = qemu_coroutine_self(),
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+ .new_ctx = new_ctx,
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+ };
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+ /*
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+ * We can't directly schedule the coroutine in the target context
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+ * because this would be racy: The other thread could try to enter the
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+ * coroutine before it has yielded in this one.
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+ */
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+ aio_bh_schedule_oneshot(old_ctx, aio_co_reschedule_self_bh, &data);
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+ qemu_coroutine_yield();
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+ }
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+}
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+
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void aio_co_wake(struct Coroutine *co)
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{
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AioContext *ctx;
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