[PULL 0/2] Block patches
[Qemu-devel] [PULL for-2.11-rc1 v2 0/2] Block patches
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The following changes since commit ca61fa4b803e5d0abaf6f1ceb690f23bb78a4def:
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The following changes since commit b0fbe46ad82982b289a44ee2495b59b0bad8a842:
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Merge remote-tracking branch 'remotes/quic/tags/pull-hex-20211006' into staging (2021-10-06 12:11:14 -0700)
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Update version for v2.11.0-rc0 release (2017-11-07 16:05:28 +0000)
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are available in the Git repository at:
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are available in the git repository at:
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https://gitlab.com/stefanha/qemu.git tags/block-pull-request
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git://github.com/stefanha/qemu.git tags/block-pull-request
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for you to fetch changes up to 1cc7eada97914f090125e588497986f6f7900514:
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for you to fetch changes up to ef6dada8b44e1e7c4bec5c1115903af9af415b50:
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iothread: use IOThreadParamInfo in iothread_[set|get]_param() (2021-10-07 15:29:50 +0100)
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util/async: use atomic_mb_set in qemu_bh_cancel (2017-11-08 19:09:15 +0000)
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----------------------------------------------------------------
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----------------------------------------------------------------
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Pull request
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Pull request
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v2:
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* v1 emails 2/3 and 3/3 weren't sent due to an email failure
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* Included Sergio's updated wording in the commit description
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----------------------------------------------------------------
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----------------------------------------------------------------
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Stefano Garzarella (2):
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Sergio Lopez (1):
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iothread: rename PollParamInfo to IOThreadParamInfo
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util/async: use atomic_mb_set in qemu_bh_cancel
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iothread: use IOThreadParamInfo in iothread_[set|get]_param()
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iothread.c | 28 +++++++++++++++-------------
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Stefan Hajnoczi (1):
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1 file changed, 15 insertions(+), 13 deletions(-)
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tests-aio-multithread: fix /aio/multi/schedule race condition
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tests/test-aio-multithread.c | 5 ++---
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util/async.c | 2 +-
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2 files changed, 3 insertions(+), 4 deletions(-)
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--
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--
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2.31.1
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2.13.6
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diff view generated by jsdifflib
[PULL 1/2] iothread: rename PollParamInfo to IOThreadParamInfo
[Qemu-devel] [PULL for-2.11-rc1 v2 1/2] tests-aio-multithread: fix /aio/multi/schedule race condition
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From: Stefano Garzarella <sgarzare@redhat.com>
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test_multi_co_schedule_entry() set to_schedule[id] in the final loop
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iteration before terminating the coroutine. There is a race condition
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where the main thread attempts to enter the terminating or terminated
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coroutine when signalling coroutines to stop:
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Commit 1793ad0247 ("iothread: add aio-max-batch parameter") added
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atomic_mb_set(&now_stopping, true);
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a new parameter (aio-max-batch) to IOThread and used PollParamInfo
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for (i = 0; i < NUM_CONTEXTS; i++) {
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structure to handle it.
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ctx_run(i, finish_cb, NULL); <--- enters dead coroutine!
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to_schedule[i] = NULL;
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}
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Since it is not a parameter of the polling mechanism, we rename the
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Make sure only to set to_schedule[id] if this coroutine really needs to
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structure to a more generic IOThreadParamInfo.
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be scheduled!
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Suggested-by: Kevin Wolf <kwolf@redhat.com>
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Reported-by: "R.Nageswara Sastry" <nasastry@in.ibm.com>
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Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
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Message-id: 20210727145936.147032-2-sgarzare@redhat.com
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Message-id: 20171106190233.1175-1-stefanha@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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---
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iothread.c | 14 +++++++-------
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tests/test-aio-multithread.c | 5 ++---
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1 file changed, 7 insertions(+), 7 deletions(-)
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1 file changed, 2 insertions(+), 3 deletions(-)
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diff --git a/iothread.c b/iothread.c
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diff --git a/tests/test-aio-multithread.c b/tests/test-aio-multithread.c
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index XXXXXXX..XXXXXXX 100644
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index XXXXXXX..XXXXXXX 100644
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--- a/iothread.c
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--- a/tests/test-aio-multithread.c
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+++ b/iothread.c
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+++ b/tests/test-aio-multithread.c
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@@ -XXX,XX +XXX,XX @@ static void iothread_complete(UserCreatable *obj, Error **errp)
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@@ -XXX,XX +XXX,XX @@ static void finish_cb(void *opaque)
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typedef struct {
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static coroutine_fn void test_multi_co_schedule_entry(void *opaque)
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const char *name;
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ptrdiff_t offset; /* field's byte offset in IOThread struct */
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-} PollParamInfo;
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+} IOThreadParamInfo;
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-static PollParamInfo poll_max_ns_info = {
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+static IOThreadParamInfo poll_max_ns_info = {
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"poll-max-ns", offsetof(IOThread, poll_max_ns),
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};
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-static PollParamInfo poll_grow_info = {
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+static IOThreadParamInfo poll_grow_info = {
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"poll-grow", offsetof(IOThread, poll_grow),
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};
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-static PollParamInfo poll_shrink_info = {
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+static IOThreadParamInfo poll_shrink_info = {
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"poll-shrink", offsetof(IOThread, poll_shrink),
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};
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-static PollParamInfo aio_max_batch_info = {
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+static IOThreadParamInfo aio_max_batch_info = {
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"aio-max-batch", offsetof(IOThread, aio_max_batch),
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};
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@@ -XXX,XX +XXX,XX @@ static void iothread_get_param(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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{
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IOThread *iothread = IOTHREAD(obj);
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g_assert(to_schedule[id] == NULL);
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- PollParamInfo *info = opaque;
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- atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
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+ IOThreadParamInfo *info = opaque;
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int64_t *field = (void *)iothread + info->offset;
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while (!atomic_mb_read(&now_stopping)) {
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int n;
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visit_type_int64(v, name, field, errp);
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@@ -XXX,XX +XXX,XX @@ static bool iothread_set_param(Object *obj, Visitor *v,
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n = g_test_rand_int_range(0, NUM_CONTEXTS);
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const char *name, void *opaque, Error **errp)
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schedule_next(n);
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{
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+
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IOThread *iothread = IOTHREAD(obj);
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+ atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
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- PollParamInfo *info = opaque;
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qemu_coroutine_yield();
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+ IOThreadParamInfo *info = opaque;
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-
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int64_t *field = (void *)iothread + info->offset;
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g_assert(to_schedule[id] == NULL);
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int64_t value;
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- atomic_mb_set(&to_schedule[id], qemu_coroutine_self());
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}
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}
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--
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--
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2.31.1
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2.13.6
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68
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diff view generated by jsdifflib
[PULL 2/2] iothread: use IOThreadParamInfo in iothread_[set|get]_param()
[Qemu-devel] [PULL for-2.11-rc1 v2 2/2] util/async: use atomic_mb_set in qemu_bh_cancel
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From: Stefano Garzarella <sgarzare@redhat.com>
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From: Sergio Lopez <slp@redhat.com>
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Commit 0445409d74 ("iothread: generalize
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Commit b7a745d added a qemu_bh_cancel call to the completion function
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iothread_set_param/iothread_get_param") moved common code to set and
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as an optimization to prevent it from unnecessarily rescheduling itself.
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get IOThread parameters in two new functions.
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These functions are called inside callbacks, so we don't need to use an
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This completion function is scheduled from worker_thread, after setting
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opaque pointer. Let's replace `void *opaque` parameter with
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the state of a ThreadPoolElement to THREAD_DONE.
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`IOThreadParamInfo *info`.
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Suggested-by: Kevin Wolf <kwolf@redhat.com>
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This was considered to be safe, as the completion function restarts the
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Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
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loop just after the call to qemu_bh_cancel. But, as this loop lacks a HW
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Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
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memory barrier, the read of req->state may actually happen _before_ the
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Message-id: 20210727145936.147032-3-sgarzare@redhat.com
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call, seeing it still as THREAD_QUEUED, and ending the completion
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function without having processed a pending TPE linked at pool->head:
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worker thread | I/O thread
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------------------------------------------------------------------------
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| speculatively read req->state
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req->state = THREAD_DONE; |
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qemu_bh_schedule(p->completion_bh) |
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bh->scheduled = 1; |
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| qemu_bh_cancel(p->completion_bh)
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| bh->scheduled = 0;
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| if (req->state == THREAD_DONE)
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| // sees THREAD_QUEUED
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The source of the misunderstanding was that qemu_bh_cancel is now being
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used by the _consumer_ rather than the producer, and therefore now needs
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to have acquire semantics just like e.g. aio_bh_poll.
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In some situations, if there are no other independent requests in the
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same aio context that could eventually trigger the scheduling of the
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completion function, the omitted TPE and all operations pending on it
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will get stuck forever.
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[Added Sergio's updated wording about the HW memory barrier.
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--Stefan]
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Signed-off-by: Sergio Lopez <slp@redhat.com>
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Message-id: 20171108063447.2842-1-slp@redhat.com
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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---
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iothread.c | 18 ++++++++++--------
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util/async.c | 2 +-
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1 file changed, 10 insertions(+), 8 deletions(-)
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/iothread.c b/iothread.c
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diff --git a/util/async.c b/util/async.c
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index XXXXXXX..XXXXXXX 100644
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index XXXXXXX..XXXXXXX 100644
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--- a/iothread.c
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--- a/util/async.c
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+++ b/iothread.c
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+++ b/util/async.c
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@@ -XXX,XX +XXX,XX @@ static IOThreadParamInfo aio_max_batch_info = {
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@@ -XXX,XX +XXX,XX @@ void qemu_bh_schedule(QEMUBH *bh)
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};
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*/
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void qemu_bh_cancel(QEMUBH *bh)
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static void iothread_get_param(Object *obj, Visitor *v,
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- const char *name, void *opaque, Error **errp)
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+ const char *name, IOThreadParamInfo *info, Error **errp)
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{
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{
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IOThread *iothread = IOTHREAD(obj);
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- bh->scheduled = 0;
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- IOThreadParamInfo *info = opaque;
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+ atomic_mb_set(&bh->scheduled, 0);
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int64_t *field = (void *)iothread + info->offset;
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visit_type_int64(v, name, field, errp);
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}
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}
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static bool iothread_set_param(Object *obj, Visitor *v,
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/* This func is async.The bottom half will do the delete action at the finial
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- const char *name, void *opaque, Error **errp)
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+ const char *name, IOThreadParamInfo *info, Error **errp)
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{
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IOThread *iothread = IOTHREAD(obj);
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- IOThreadParamInfo *info = opaque;
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int64_t *field = (void *)iothread + info->offset;
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int64_t value;
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@@ -XXX,XX +XXX,XX @@ static bool iothread_set_param(Object *obj, Visitor *v,
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static void iothread_get_poll_param(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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+ IOThreadParamInfo *info = opaque;
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- iothread_get_param(obj, v, name, opaque, errp);
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+ iothread_get_param(obj, v, name, info, errp);
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}
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static void iothread_set_poll_param(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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IOThread *iothread = IOTHREAD(obj);
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+ IOThreadParamInfo *info = opaque;
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- if (!iothread_set_param(obj, v, name, opaque, errp)) {
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+ if (!iothread_set_param(obj, v, name, info, errp)) {
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return;
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}
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@@ -XXX,XX +XXX,XX @@ static void iothread_set_poll_param(Object *obj, Visitor *v,
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static void iothread_get_aio_param(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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+ IOThreadParamInfo *info = opaque;
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- iothread_get_param(obj, v, name, opaque, errp);
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+ iothread_get_param(obj, v, name, info, errp);
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}
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static void iothread_set_aio_param(Object *obj, Visitor *v,
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const char *name, void *opaque, Error **errp)
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{
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IOThread *iothread = IOTHREAD(obj);
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+ IOThreadParamInfo *info = opaque;
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- if (!iothread_set_param(obj, v, name, opaque, errp)) {
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+ if (!iothread_set_param(obj, v, name, info, errp)) {
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return;
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}
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--
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--
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2.31.1
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2.13.6
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diff view generated by jsdifflib

Patchew 2.1-devel-b67e4c2

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