-----BEGIN PGP SIGNATURE-----
iQEcBAABAgAGBQJaulgHAAoJEJykq7OBq3PI0owH/3isnzyO8efBzlv4HlWb1qV0 F7m9urAKZm1QLCkJBlli/G5iNaNUfrXSum4qYK22XAiwV5WAoPAjwrOvtTRRTSfW vFGAucmf6NKkomuZRAiPQftqR+DL9VhBC7mcdRwfwWZ82AGZZnAQsDf8y9e3kal2 YPwogmvQi+bn2Psv6q3zYtrTW9bC1VJWzYFP4xcSpcxGOY/WfLhPX9nrhjQz07mm h/y9mWqXA8PytmopMLj31xRmhTSndIwo+uvScLH95UXRuAOhjyHMvvD4HfI4nkR+ WD94pE6UiUpIdCZ6fh8H/jaCpN8jPnXI4XJg9cQcRHZYkOrHwQ8G1xxoOintjW0= =55b0 -----END PGP SIGNATURE----- Merge remote-tracking branch 'remotes/stefanha/tags/block-pull-request' into staging # gpg: Signature made Tue 27 Mar 2018 15:41:11 BST # gpg: using RSA key 9CA4ABB381AB73C8 # gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" # gpg: aka "Stefan Hajnoczi <stefanha@gmail.com>" # Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35 775A 9CA4 ABB3 81AB 73C8 * remotes/stefanha/tags/block-pull-request: MAINTAINERS: add include/block/aio-wait.h coroutine: add test-aio coroutine queue chaining test case coroutine: avoid co_queue_wakeup recursion queue: add QSIMPLEQ_PREPEND() Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
commit
6cf38cbf29
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@ -1351,6 +1351,7 @@ F: util/aio-*.c
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F: block/io.c
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F: migration/block*
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F: include/block/aio.h
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F: include/block/aio-wait.h
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F: scripts/qemugdb/aio.py
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T: git git://github.com/stefanha/qemu.git block
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@ -249,8 +249,7 @@ static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
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BdrvCoDrainData data;
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/* Calling bdrv_drain() from a BH ensures the current coroutine yields and
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* other coroutines run if they were queued from
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* qemu_co_queue_run_restart(). */
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* other coroutines run if they were queued by aio_co_enter(). */
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assert(qemu_in_coroutine());
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data = (BdrvCoDrainData) {
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@ -68,6 +68,5 @@ Coroutine *qemu_coroutine_new(void);
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void qemu_coroutine_delete(Coroutine *co);
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CoroutineAction qemu_coroutine_switch(Coroutine *from, Coroutine *to,
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CoroutineAction action);
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void coroutine_fn qemu_co_queue_run_restart(Coroutine *co);
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#endif
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@ -324,6 +324,14 @@ struct { \
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} \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_PREPEND(head1, head2) do { \
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if (!QSIMPLEQ_EMPTY((head2))) { \
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*(head2)->sqh_last = (head1)->sqh_first; \
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(head1)->sqh_first = (head2)->sqh_first; \
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QSIMPLEQ_INIT((head2)); \
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} \
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} while (/*CONSTCOND*/0)
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#define QSIMPLEQ_LAST(head, type, field) \
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(QSIMPLEQ_EMPTY((head)) ? \
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NULL : \
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@ -16,6 +16,8 @@
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#include "qemu/timer.h"
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#include "qemu/sockets.h"
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#include "qemu/error-report.h"
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#include "qemu/coroutine.h"
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#include "qemu/main-loop.h"
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static AioContext *ctx;
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@ -827,24 +829,59 @@ static void test_source_timer_schedule(void)
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timer_del(&data.timer);
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}
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/*
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* Check that aio_co_enter() can chain many times
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*
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* Two coroutines should be able to invoke each other via aio_co_enter() many
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* times without hitting a limit like stack exhaustion. In other words, the
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* calls should be chained instead of nested.
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*/
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typedef struct {
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Coroutine *other;
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unsigned i;
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unsigned max;
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} ChainData;
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static void coroutine_fn chain(void *opaque)
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{
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ChainData *data = opaque;
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for (data->i = 0; data->i < data->max; data->i++) {
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/* Queue up the other coroutine... */
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aio_co_enter(ctx, data->other);
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/* ...and give control to it */
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qemu_coroutine_yield();
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}
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}
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static void test_queue_chaining(void)
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{
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/* This number of iterations hit stack exhaustion in the past: */
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ChainData data_a = { .max = 25000 };
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ChainData data_b = { .max = 25000 };
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data_b.other = qemu_coroutine_create(chain, &data_a);
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data_a.other = qemu_coroutine_create(chain, &data_b);
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qemu_coroutine_enter(data_b.other);
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g_assert_cmpint(data_a.i, ==, data_a.max);
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g_assert_cmpint(data_b.i, ==, data_b.max - 1);
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/* Allow the second coroutine to terminate */
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qemu_coroutine_enter(data_a.other);
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g_assert_cmpint(data_b.i, ==, data_b.max);
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}
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/* End of tests. */
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int main(int argc, char **argv)
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{
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Error *local_error = NULL;
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GSource *src;
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init_clocks(NULL);
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ctx = aio_context_new(&local_error);
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if (!ctx) {
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error_reportf_err(local_error, "Failed to create AIO Context: ");
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exit(1);
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}
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src = aio_get_g_source(ctx);
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g_source_attach(src, NULL);
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g_source_unref(src);
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qemu_init_main_loop(&error_fatal);
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ctx = qemu_get_aio_context();
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while (g_main_context_iteration(NULL, false));
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@ -864,6 +901,8 @@ int main(int argc, char **argv)
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g_test_add_func("/aio/external-client", test_aio_external_client);
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g_test_add_func("/aio/timer/schedule", test_timer_schedule);
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g_test_add_func("/aio/coroutine/queue-chaining", test_queue_chaining);
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g_test_add_func("/aio-gsource/flush", test_source_flush);
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g_test_add_func("/aio-gsource/bh/schedule", test_source_bh_schedule);
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g_test_add_func("/aio-gsource/bh/schedule10", test_source_bh_schedule10);
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@ -68,40 +68,6 @@ void coroutine_fn qemu_co_queue_wait_impl(CoQueue *queue, QemuLockable *lock)
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}
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}
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/**
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* qemu_co_queue_run_restart:
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*
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* Enter each coroutine that was previously marked for restart by
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* qemu_co_queue_next() or qemu_co_queue_restart_all(). This function is
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* invoked by the core coroutine code when the current coroutine yields or
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* terminates.
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*/
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void qemu_co_queue_run_restart(Coroutine *co)
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{
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Coroutine *next;
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QSIMPLEQ_HEAD(, Coroutine) tmp_queue_wakeup =
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QSIMPLEQ_HEAD_INITIALIZER(tmp_queue_wakeup);
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trace_qemu_co_queue_run_restart(co);
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/* Because "co" has yielded, any coroutine that we wakeup can resume it.
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* If this happens and "co" terminates, co->co_queue_wakeup becomes
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* invalid memory. Therefore, use a temporary queue and do not touch
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* the "co" coroutine as soon as you enter another one.
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*
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* In its turn resumed "co" can populate "co_queue_wakeup" queue with
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* new coroutines to be woken up. The caller, who has resumed "co",
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* will be responsible for traversing the same queue, which may cause
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* a different wakeup order but not any missing wakeups.
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*/
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QSIMPLEQ_CONCAT(&tmp_queue_wakeup, &co->co_queue_wakeup);
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while ((next = QSIMPLEQ_FIRST(&tmp_queue_wakeup))) {
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QSIMPLEQ_REMOVE_HEAD(&tmp_queue_wakeup, co_queue_next);
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qemu_coroutine_enter(next);
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}
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}
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static bool qemu_co_queue_do_restart(CoQueue *queue, bool single)
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{
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Coroutine *next;
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@ -104,57 +104,65 @@ static void coroutine_delete(Coroutine *co)
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void qemu_aio_coroutine_enter(AioContext *ctx, Coroutine *co)
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{
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Coroutine *self = qemu_coroutine_self();
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CoroutineAction ret;
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QSIMPLEQ_HEAD(, Coroutine) pending = QSIMPLEQ_HEAD_INITIALIZER(pending);
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Coroutine *from = qemu_coroutine_self();
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/* Cannot rely on the read barrier for co in aio_co_wake(), as there are
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* callers outside of aio_co_wake() */
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const char *scheduled = atomic_mb_read(&co->scheduled);
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QSIMPLEQ_INSERT_TAIL(&pending, co, co_queue_next);
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trace_qemu_aio_coroutine_enter(ctx, self, co, co->entry_arg);
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/* Run co and any queued coroutines */
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while (!QSIMPLEQ_EMPTY(&pending)) {
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Coroutine *to = QSIMPLEQ_FIRST(&pending);
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CoroutineAction ret;
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/* if the Coroutine has already been scheduled, entering it again will
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* cause us to enter it twice, potentially even after the coroutine has
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* been deleted */
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if (scheduled) {
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fprintf(stderr,
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"%s: Co-routine was already scheduled in '%s'\n",
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__func__, scheduled);
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abort();
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}
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/* Cannot rely on the read barrier for to in aio_co_wake(), as there are
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* callers outside of aio_co_wake() */
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const char *scheduled = atomic_mb_read(&to->scheduled);
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if (co->caller) {
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fprintf(stderr, "Co-routine re-entered recursively\n");
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abort();
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}
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QSIMPLEQ_REMOVE_HEAD(&pending, co_queue_next);
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co->caller = self;
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co->ctx = ctx;
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trace_qemu_aio_coroutine_enter(ctx, from, to, to->entry_arg);
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/* Store co->ctx before anything that stores co. Matches
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* barrier in aio_co_wake and qemu_co_mutex_wake.
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*/
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smp_wmb();
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/* if the Coroutine has already been scheduled, entering it again will
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* cause us to enter it twice, potentially even after the coroutine has
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* been deleted */
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if (scheduled) {
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fprintf(stderr,
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"%s: Co-routine was already scheduled in '%s'\n",
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__func__, scheduled);
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abort();
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}
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ret = qemu_coroutine_switch(self, co, COROUTINE_ENTER);
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if (to->caller) {
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fprintf(stderr, "Co-routine re-entered recursively\n");
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abort();
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}
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qemu_co_queue_run_restart(co);
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to->caller = from;
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to->ctx = ctx;
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/* Beware, if ret == COROUTINE_YIELD and qemu_co_queue_run_restart()
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* has started any other coroutine, "co" might have been reentered
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* and even freed by now! So be careful and do not touch it.
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*/
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/* Store to->ctx before anything that stores to. Matches
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* barrier in aio_co_wake and qemu_co_mutex_wake.
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*/
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smp_wmb();
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switch (ret) {
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case COROUTINE_YIELD:
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return;
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case COROUTINE_TERMINATE:
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assert(!co->locks_held);
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trace_qemu_coroutine_terminate(co);
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coroutine_delete(co);
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return;
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default:
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abort();
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ret = qemu_coroutine_switch(from, to, COROUTINE_ENTER);
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/* Queued coroutines are run depth-first; previously pending coroutines
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* run after those queued more recently.
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*/
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QSIMPLEQ_PREPEND(&pending, &to->co_queue_wakeup);
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switch (ret) {
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case COROUTINE_YIELD:
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break;
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case COROUTINE_TERMINATE:
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assert(!to->locks_held);
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trace_qemu_coroutine_terminate(to);
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coroutine_delete(to);
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break;
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default:
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abort();
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}
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}
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}
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