Re: [Qemu-devel] [PATCH 0/5] Spread the use of QEMU threading & locking API

[Jan Kiszka <jan.kiszka@siemens.com>]

On 2012-04-04 18:39, Paolo Bonzini wrote:
> Il 04/04/2012 18:05, Jan Kiszka ha scritto:
>>>> Perhaps you can take the relevant patches out of the thread-blocks
>>>> branch at git://github.com/pbonzini/qemu.git?  The iothread eventfd
>>>> could also use an EventNotifier.
>> Yep, this screams for something like QemuEvent which pleases all users
>> of current qemu_eventfd and EventNotifier - and fit into the existing
>> threading/synchronization abstraction layout.
> 
> Kind of, on Unix you cannot poll synchronization primitives so
> EventNotifier has to remain separate from qemu-thread.

QemuEvent will be pollable as you can ask it for its read fd:

void qemu_event_init(QemuEvent *event, bool signaled);
void qemu_event_destroy(QemuEvent *event);
int qemu_event_get_write_fd(QemuEvent *event);
int qemu_event_get_read_fd(QemuEvent *event);
void qemu_event_signal(QemuEvent *event);
bool qemu_event_check(QemuEvent *event);

I'm not yet convinced a qemu_event_set_handler buys us a lot, so I
prefer the get_read_fd interface for now.

This is just a matter of code organization, and I prefer to consolidate
this under the hood of qemu-thread.

Jan

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