From: Paolo Bonzini <pbonzini@redhat.com>
To: Eric Blake <eblake@redhat.com>
Cc: kwolf@redhat.com, stefanha@gmail.com, aliguori@us.ibm.com,
Wenchao Xia <xiawenc@linux.vnet.ibm.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 1/6] libqblock APIs
Date: Tue, 04 Sep 2012 15:47:55 +0200 [thread overview]
Message-ID: <5046068B.3000702@redhat.com> (raw)
In-Reply-To: <5045E78D.1080100@redhat.com>
Il 04/09/2012 13:35, Eric Blake ha scritto:
>> > No, it should be only called once, any other thread should not call
>> > it again, will document it. About the multiple thread user case, qemu
>> > block layer can't support that now, will fix that later.
> What a shame. That makes libraries much harder to use. It is much
> nicer to design a library where the initialization is idempotent and
> thread-safe, to be called from multiple threads. Consider:
>
> app links against liba and libb;
> liba links against libqb
> libb links against libqb
>
> How am I supposed to write liba and libb to guarantee only one single
> race-free call to libqblock_init, unless libqblock_init() is idempotent?
I agree, libqblock_init should use pthread_once (or we can add QemuOnce
to qemu-thread-*.c).
Paolo
next prev parent reply other threads:[~2012-09-04 13:48 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-03 9:18 [Qemu-devel] [PATCH 0/6] libqblock, qemu block layer library Wenchao Xia
2012-09-03 9:18 ` [Qemu-devel] [PATCH 1/6] libqblock APIs Wenchao Xia
2012-09-03 13:18 ` Paolo Bonzini
2012-09-04 3:15 ` Wenchao Xia
2012-09-04 6:50 ` Paolo Bonzini
2012-09-04 9:05 ` Wenchao Xia
2012-09-10 8:10 ` Wenchao Xia
2012-09-03 13:56 ` Eric Blake
2012-09-03 14:05 ` Paolo Bonzini
2012-09-04 7:05 ` Wenchao Xia
2012-09-04 7:29 ` Paolo Bonzini
2012-09-04 6:42 ` Wenchao Xia
2012-09-04 11:35 ` Eric Blake
2012-09-04 13:47 ` Paolo Bonzini [this message]
2012-09-03 19:22 ` Blue Swirl
2012-09-03 9:18 ` [Qemu-devel] [PATCH 2/6] libqblock public type defines Wenchao Xia
2012-09-03 13:13 ` Paolo Bonzini
2012-09-04 2:00 ` Wenchao Xia
2012-09-03 14:20 ` Eric Blake
2012-09-04 7:10 ` Wenchao Xia
2012-09-04 7:37 ` Paolo Bonzini
2012-09-03 19:31 ` Blue Swirl
2012-09-04 7:19 ` Wenchao Xia
2012-09-04 7:38 ` Paolo Bonzini
2012-09-04 19:22 ` Blue Swirl
2012-09-10 8:22 ` Wenchao Xia
2012-09-03 9:18 ` [Qemu-devel] [PATCH 3/6] libqblock error handling Wenchao Xia
2012-09-03 14:22 ` Eric Blake
2012-09-04 7:12 ` Wenchao Xia
2012-09-10 8:20 ` Wenchao Xia
2012-09-03 9:18 ` [Qemu-devel] [PATCH 4/6] libqblock internal used functions Wenchao Xia
2012-09-03 13:18 ` Paolo Bonzini
2012-09-04 3:19 ` Wenchao Xia
2012-09-03 14:28 ` Eric Blake
2012-09-03 15:18 ` Paolo Bonzini
2012-09-04 7:15 ` Wenchao Xia
2012-09-04 7:38 ` Paolo Bonzini
2012-09-04 11:38 ` Eric Blake
2012-09-04 13:49 ` Paolo Bonzini
2012-09-04 13:51 ` Kevin Wolf
2012-09-10 8:23 ` Wenchao Xia
2012-09-03 9:18 ` [Qemu-devel] [PATCH 5/6] libqblock test example Wenchao Xia
2012-09-03 19:27 ` Blue Swirl
2012-09-03 9:18 ` [Qemu-devel] [PATCH 6/6] libqblock building system Wenchao Xia
2012-09-03 13:10 ` [Qemu-devel] xbzrle migration cache size advise for high memory changes workload ? Alexandre DERUMIER
2012-09-04 14:05 ` Orit Wasserman
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