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| author | Paolo Bonzini | 2016-09-19 11:10:57 +0200 |
|---|---|---|
| committer | Paolo Bonzini | 2016-10-24 11:30:55 +0200 |
| commit | 374293ca6fb060f0302e5ca76ddccbc2bbb075c9 (patch) | |
| tree | dc95662c0cdcc77ecf1e2f2416756ef05a146f79 /docs | |
| parent | atomic: introduce smp_mb_acquire and smp_mb_release (diff) | |
| download | qemu-374293ca6fb060f0302e5ca76ddccbc2bbb075c9.tar.gz qemu-374293ca6fb060f0302e5ca76ddccbc2bbb075c9.tar.xz qemu-374293ca6fb060f0302e5ca76ddccbc2bbb075c9.zip | |
qemu-thread: use acquire/release to clarify semantics of QemuEvent
Do not use the somewhat mysterious atomic_mb_read/atomic_mb_set,
instead make sure that the operations on QemuEvent are annotated
with the desired acquire and release semantics.
In particular, qemu_event_set wakes up the waiting thread, so it must
be a release from the POV of the waker (compare with qemu_mutex_unlock).
And it actually needs a full barrier, because that's the only thing that
provides something like a "load-release".
Use smp_mb_acquire until we have atomic_load_acquire and
atomic_store_release in atomic.h.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'docs')
0 files changed, 0 insertions, 0 deletions