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Re: [Qemu-devel] [PATCH 02/10] qemu-thread: introduce QemuLockCnt
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From: |
Stefan Hajnoczi |
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Subject: |
Re: [Qemu-devel] [PATCH 02/10] qemu-thread: introduce QemuLockCnt |
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Date: |
Wed, 11 Jan 2017 16:35:35 +0000 |
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User-agent: |
Mutt/1.7.1 (2016-10-04) |
On Wed, Jan 04, 2017 at 02:26:17PM +0100, Paolo Bonzini wrote:
> +/* Decrement a counter, and return locked if it is decremented to zero.
> + * It is impossible for the counter to become nonzero while the mutex
> + * is taken.
> + */
> +bool qemu_lockcnt_dec_and_lock(QemuLockCnt *lockcnt)
> +{
> + int val = atomic_read(&lockcnt->count);
Why does qemu_lockcnt_inc() use atomic_mb_read() while this function
uses plain atomic_read()?
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- [Qemu-devel] [PATCH v3 00/10] aio_context_acquire/release pushdown, part 1, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 01/10] aio: rename bh_lock to list_lock, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 03/10] aio: make ctx->list_lock a QemuLockCnt, subsuming ctx->walking_bh, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 05/10] aio-posix: split aio_dispatch_handlers out of aio_dispatch, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 02/10] qemu-thread: introduce QemuLockCnt, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 04/10] qemu-thread: optimize QemuLockCnt with futexes on Linux, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 06/10] aio: tweak walking in dispatch phase, Paolo Bonzini, 2017/01/04
- [Qemu-devel] [PATCH 07/10] aio-posix: remove walking_handlers, protecting AioHandler list with list_lock, Paolo Bonzini, 2017/01/04