qemu/util
Kevin Wolf cfe29d8294 block: Use a single global AioWait
When draining a block node, we recurse to its parent and for subtree
drains also to its children. A single AIO_WAIT_WHILE() is then used to
wait for bdrv_drain_poll() to become true, which depends on all of the
nodes we recursed to. However, if the respective child or parent becomes
quiescent and calls bdrv_wakeup(), only the AioWait of the child/parent
is checked, while AIO_WAIT_WHILE() depends on the AioWait of the
original node.

Fix this by using a single AioWait for all callers of AIO_WAIT_WHILE().

This may mean that the draining thread gets a few more unnecessary
wakeups because an unrelated operation got completed, but we already
wake it up when something _could_ have changed rather than only if it
has certainly changed.

Apart from that, drain is a slow path anyway. In theory it would be
possible to use wakeups more selectively and still correctly, but the
gains are likely not worth the additional complexity. In fact, this
patch is a nice simplification for some places in the code.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
2018-09-25 15:50:15 +02:00
..
Makefile.objs ui: misc fixes which piled up during 3.0 release freeze 2018-08-27 12:30:51 +01:00
acl.c Drop Emacs local variables lists redundant with .dir-locals.el 2016-07-12 16:19:16 +02:00
aio-posix.c aio-posix: Improve comment around marking node deleted 2018-08-15 10:12:35 +08:00
aio-wait.c block: Use a single global AioWait 2018-09-25 15:50:15 +02:00
aio-win32.c aio: Do aio_notify_accept only during blocking aio_poll 2018-08-15 10:12:35 +08:00
aiocb.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
async.c util/async: use qemu_aio_coroutine_enter in co_schedule_bh_cb 2018-09-25 15:50:15 +02:00
base64.c include/qemu/osdep.h: Don't include qapi/error.h 2016-03-22 22:20:15 +01:00
bitmap.c bitmap: provide to_le/from_le helpers 2017-09-22 14:11:25 +02:00
bitops.c bitmap: remove BITOP_WORD() 2017-09-22 14:11:23 +02:00
buffer.c qemu-common: stop including qemu/host-utils.h from qemu-common.h 2016-05-19 16:42:28 +02:00
bufferiszero.c util: Introduce include/qemu/cpuid.h 2017-07-24 12:42:55 +01:00
cacheinfo.c configure: Drop AIX host support 2017-09-07 19:02:30 +01:00
compatfd.c cpus: remove ugly cast on sigbus_handler 2017-03-03 16:40:02 +01:00
coroutine-sigaltstack.c coroutine-sigaltstack: use helper for allocating stack memory 2016-09-29 14:13:39 +02:00
coroutine-ucontext.c build: try improve handling of clang warnings 2018-03-12 08:59:03 +01:00
coroutine-win32.c coroutine: add a macro for the coroutine stack size 2016-09-29 14:13:39 +02:00
crc32c.c util: Clean up includes 2016-02-04 17:01:04 +00:00
cutils.c cutils: Provide strchrnul 2018-06-29 12:32:10 +02:00
drm.c util: promote qemu_egl_rendernode_open() to libqemuutil 2018-08-27 10:51:44 +02:00
envlist.c util: Use g_malloc/g_free in envlist.c 2017-05-07 09:57:51 +03:00
error.c error: Implement the warn and free Error functions 2017-07-13 13:50:19 +02:00
event_notifier-posix.c Revert "qemu: add a cleanup callback function to EventNotifier" 2018-01-24 19:20:19 +02:00
event_notifier-win32.c Revert "qemu: add a cleanup callback function to EventNotifier" 2018-01-24 19:20:19 +02:00
fifo8.c migration: consolidate VMStateField.start 2017-02-13 17:27:13 +00:00
getauxval.c util: Clean up includes 2016-02-04 17:01:04 +00:00
hbitmap.c hbitmap: Add @advance param to hbitmap_iter_next() 2018-06-18 17:04:55 +02:00
hexdump.c util: Improved qemu_hexmap() to include an ascii dump of the buffer 2016-04-06 09:52:07 +08:00
host-utils.c host-utils: Implement unsigned quadword left/right shift and unit tests 2017-01-31 10:10:14 +11:00
id.c util: move declarations out of qemu-common.h 2016-03-22 22:20:17 +01:00
iohandler.c block: move AioContext, QEMUTimer, main-loop to libqemuutil 2017-02-21 11:14:07 +00:00
iov.c util: Fix assertion in iov_copy() upon zero 'bytes' and non-zero 'offset' 2016-08-03 18:44:57 +02:00
iova-tree.c util: remove redundant include of glib.h and add osdep.h 2018-06-29 12:22:28 +01:00
keyval.c qobject: Replace qobject_incref/QINCREF qobject_decref/QDECREF 2018-05-04 08:27:53 +02:00
lockcnt.c qemu-thread: optimize QemuLockCnt with futexes on Linux 2017-01-16 13:25:18 +00:00
log.c tcg: Optionally log FPU state in TCG -d cpu logging 2018-05-15 14:58:44 +01:00
main-loop.c main-loop: drop spin_counter 2018-06-01 16:01:29 +01:00
memfd.c memfd: Avoid Coverity warning about integer overflow 2018-06-01 15:13:46 +02:00
mmap-alloc.c Make qemu_mempath_getpagesize() accept NULL 2018-04-27 18:05:22 +10:00
module.c module: Use QEMU_MODULE_DIR as a search path 2018-08-23 18:46:25 +02:00
notify.c util: Clean up includes 2016-02-04 17:01:04 +00:00
osdep.c glib: bump min required glib library version to 2.40 2018-06-29 12:22:28 +01:00
oslib-posix.c mem: add share parameter to memory-backend-ram 2018-02-19 13:03:24 +02:00
oslib-win32.c util/oslib-win32: indicate alignment for qemu_anon_ram_alloc() 2018-08-23 18:46:25 +02:00
pagesize.c util: move qemu_real_host_page_size/mask to osdep.h 2017-10-10 09:45:00 -07:00
path.c util: Removed unneeded header from path.c 2017-03-14 13:26:37 +01:00
qdist.c qdist: return "(empty)" instead of NULL when printing an empty dist 2016-08-03 18:44:56 +02:00
qemu-config.c block: Add block-specific QDict header 2018-06-15 14:49:44 +02:00
qemu-coroutine-io.c coroutine: move entry argument to qemu_coroutine_create 2016-07-13 13:26:02 +02:00
qemu-coroutine-lock.c coroutine: avoid co_queue_wakeup recursion 2018-03-27 13:05:28 +01:00
qemu-coroutine-sleep.c coroutine: simplify co_aio_sleep_ns() prototype 2017-12-19 09:25:27 +00:00
qemu-coroutine.c block: Add missing locking in bdrv_co_drain_bh_cb() 2018-09-25 15:50:15 +02:00
qemu-error.c qemu-error: add {error, warn}_report_once_cond 2018-09-24 17:13:07 +02:00
qemu-openpty.c util: Clean up includes 2016-02-04 17:01:04 +00:00
qemu-option.c opts: remove redundant check for NULL parameter 2018-07-17 16:24:50 +02:00
qemu-progress.c progress: Show current progress on SIGINFO 2017-04-28 18:48:11 +02:00
qemu-sockets.c sockets: allow SocketAddress 'fd' to reference numeric file descriptors 2018-03-13 18:06:06 +00:00
qemu-thread-common.h QemuMutex: support --enable-debug-mutex 2018-06-28 19:05:32 +02:00
qemu-thread-posix.c qemu-thread: introduce qemu-thread-common.h 2018-06-28 19:05:31 +02:00
qemu-thread-win32.c qsp: QEMU's Synchronization Profiler 2018-08-23 18:46:25 +02:00
qemu-timer-common.c util: Clean up includes 2016-02-04 17:01:04 +00:00
qemu-timer.c timer: remove replay clock probe in deadline calculation 2018-07-30 14:00:11 +02:00
qht.c qsp: QEMU's Synchronization Profiler 2018-08-23 18:46:25 +02:00
qsp.c qsp: track BQL callers explicitly 2018-08-23 18:46:25 +02:00
range.c range: Replace internal representation of Range 2016-07-04 16:49:33 +03:00
rcu.c membarrier: introduce qemu/sys_membarrier.h 2018-03-12 16:12:47 +01:00
readline.c readline: don't free completions in readline_free() 2018-02-05 13:54:39 +01:00
stats64.c util/stats64: Fix min/max comparisons 2017-11-15 09:34:51 +01:00
sys_membarrier.c sys_membarrier: fix up include directives 2018-04-05 14:37:38 +02:00
systemd.c qemu-ga: obey LISTEN_PID when using systemd socket activation 2017-03-19 11:12:12 +01:00
thread-pool.c thread-pool: add missing qemu_bh_cancel in completion function 2017-03-17 12:54:21 +01:00
throttle.c throttle: Assert that bkt->max is valid in throttle_compute_wait() 2017-09-26 14:46:23 +02:00
timed-average.c Fix some typos found by codespell 2016-05-18 15:04:27 +03:00
trace-events util: Introduce vfio helpers 2018-02-08 09:22:03 +08:00
unicode.c json: Reject invalid UTF-8 sequences 2018-08-24 20:26:37 +02:00
uri.c cutils: Provide strchrnul 2018-06-29 12:32:10 +02:00
uuid.c util: add is_equal to UUID API 2017-12-20 22:01:24 +08:00
vfio-helpers.c replace functions which are only available in glib-2.24 2018-05-20 08:55:01 +03:00