Revision d80b60fc2433cc934533f594bfa4e2b6c6103ba3 authored by Alberto Garcia on 08 June 2018, 15:15:36 UTC, committed by Michael Roth on 21 June 2018, 01:45:06 UTC
The throttle block filter can be reopened, and with this it is
possible to change the throttle group that the filter belongs to.
The way the code does that is the following:
- On throttle_reopen_prepare(): create a new ThrottleGroupMember
and attach it to the new throttle group.
- On throttle_reopen_commit(): detach the old ThrottleGroupMember,
delete it and replace it with the new one.
The problem with this is that by replacing the ThrottleGroupMember the
previous value of io_limits_disabled is lost, causing an assertion
failure in throttle_co_drain_end().
This problem can be reproduced by reopening a throttle node:
$QEMU -monitor stdio
-object throttle-group,id=tg0,x-iops-total=1000 \
-blockdev node-name=hd0,driver=qcow2,file.driver=file,file.filename=hd.qcow2 \
-blockdev node-name=root,driver=throttle,throttle-group=tg0,file=hd0,read-only=on
(qemu) block_stream root
block/throttle.c:214: throttle_co_drain_end: Assertion `tgm->io_limits_disabled' failed.
Since we only want to change the throttle group on reopen there's no
need to create a ThrottleGroupMember and discard the old one. It's
easier if we simply detach it from its current group and attach it to
the new one.
Signed-off-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180608151536.7378-1-berto@igalia.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
(cherry picked from commit bc33c047d1ec0b35c9cd8be62bcefae2da28654f)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
1 parent f647a4f
trace-events
# See docs/devel/tracing.txt for syntax documentation.
# util/aio-posix.c
run_poll_handlers_begin(void *ctx, int64_t max_ns) "ctx %p max_ns %"PRId64
run_poll_handlers_end(void *ctx, bool progress) "ctx %p progress %d"
poll_shrink(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
poll_grow(void *ctx, int64_t old, int64_t new) "ctx %p old %"PRId64" new %"PRId64
# util/async.c
aio_co_schedule(void *ctx, void *co) "ctx %p co %p"
aio_co_schedule_bh_cb(void *ctx, void *co) "ctx %p co %p"
# util/thread-pool.c
thread_pool_submit(void *pool, void *req, void *opaque) "pool %p req %p opaque %p"
thread_pool_complete(void *pool, void *req, void *opaque, int ret) "pool %p req %p opaque %p ret %d"
thread_pool_cancel(void *req, void *opaque) "req %p opaque %p"
# util/buffer.c
buffer_resize(const char *buf, size_t olen, size_t len) "%s: old %zd, new %zd"
buffer_move_empty(const char *buf, size_t len, const char *from) "%s: %zd bytes from %s"
buffer_move(const char *buf, size_t len, const char *from) "%s: %zd bytes from %s"
buffer_free(const char *buf, size_t len) "%s: capacity %zd"
# util/qemu-coroutine.c
qemu_aio_coroutine_enter(void *ctx, void *from, void *to, void *opaque) "ctx %p from %p to %p opaque %p"
qemu_coroutine_yield(void *from, void *to) "from %p to %p"
qemu_coroutine_terminate(void *co) "self %p"
# util/qemu-coroutine-lock.c
qemu_co_queue_run_restart(void *co) "co %p"
qemu_co_mutex_lock_uncontended(void *mutex, void *self) "mutex %p self %p"
qemu_co_mutex_lock_entry(void *mutex, void *self) "mutex %p self %p"
qemu_co_mutex_lock_return(void *mutex, void *self) "mutex %p self %p"
qemu_co_mutex_unlock_entry(void *mutex, void *self) "mutex %p self %p"
qemu_co_mutex_unlock_return(void *mutex, void *self) "mutex %p self %p"
# util/oslib-win32.c
# util/oslib-posix.c
qemu_memalign(size_t alignment, size_t size, void *ptr) "alignment %zu size %zu ptr %p"
qemu_anon_ram_alloc(size_t size, void *ptr) "size %zu ptr %p"
qemu_vfree(void *ptr) "ptr %p"
qemu_anon_ram_free(void *ptr, size_t size) "ptr %p size %zu"
# util/hbitmap.c
hbitmap_iter_skip_words(const void *hb, void *hbi, uint64_t pos, unsigned long cur) "hb %p hbi %p pos %"PRId64" cur 0x%lx"
hbitmap_reset(void *hb, uint64_t start, uint64_t count, uint64_t sbit, uint64_t ebit) "hb %p items %"PRIu64",%"PRIu64" bits %"PRIu64"..%"PRIu64
hbitmap_set(void *hb, uint64_t start, uint64_t count, uint64_t sbit, uint64_t ebit) "hb %p items %"PRIu64",%"PRIu64" bits %"PRIu64"..%"PRIu64
# util/lockcnt.c
lockcnt_fast_path_attempt(const void *lockcnt, int expected, int new) "lockcnt %p fast path %d->%d"
lockcnt_fast_path_success(const void *lockcnt, int expected, int new) "lockcnt %p fast path %d->%d succeeded"
lockcnt_unlock_attempt(const void *lockcnt, int expected, int new) "lockcnt %p unlock %d->%d"
lockcnt_unlock_success(const void *lockcnt, int expected, int new) "lockcnt %p unlock %d->%d succeeded"
lockcnt_futex_wait_prepare(const void *lockcnt, int expected, int new) "lockcnt %p preparing slow path %d->%d"
lockcnt_futex_wait(const void *lockcnt, int val) "lockcnt %p waiting on %d"
lockcnt_futex_wait_resume(const void *lockcnt, int new) "lockcnt %p after wait: %d"
lockcnt_futex_wake(const void *lockcnt) "lockcnt %p waking up one waiter"
# util/qemu-thread-posix.c
qemu_mutex_locked(void *lock) "locked mutex %p"
qemu_mutex_unlocked(void *lock) "unlocked mutex %p"
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