From: Paolo Bonzini <pbonzini@redhat.com>
To: liu ping fan <qemulist@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
qemu-devel@nongnu.org, David Gibson <david@gibson.dropbear.id.au>
Subject: Re: [Qemu-devel] [PATCH 08/12] qemu-thread: report RCU quiescent states
Date: Thu, 16 May 2013 10:43:50 +0200 [thread overview]
Message-ID: <51949C46.8000001@redhat.com> (raw)
In-Reply-To: <CAJnKYQ=oW0LiYZpWsX-cFePkuxL7ZTbjjbyrzyXwr_4S0KK_AQ@mail.gmail.com>
Il 16/05/2013 10:33, liu ping fan ha scritto:
>> > +Luckily, in most cases no manual annotation is needed, because waiting
>> > +on condition variables (qemu_cond_wait), semaphores (qemu_sem_wait,
>> > +qemu_sem_timedwait) or events (qemu_event_wait) implicitly marks the thread
>> > +as quiescent for the whole duration of the wait. (There is an exception
>> > +for semaphore waits with a zero timeout).
>> > +
> Why not the same rule for zero timeout?
>
Because they are not really doing synchronization, they are basically an
"atomic_dec_if_not_zero" on the semaphore count.
Paolo
next prev parent reply other threads:[~2013-05-16 8:44 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-15 15:48 [Qemu-devel] [RFC PATCH 00/12] RCU implementation for QEMU Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 01/12] add a header file for atomic operations Paolo Bonzini
2013-05-15 16:11 ` Peter Maydell
2013-05-15 15:48 ` [Qemu-devel] [PATCH 02/12] qemu-thread: add QemuEvent Paolo Bonzini
2013-05-16 10:15 ` Stefan Hajnoczi
2013-05-16 10:49 ` Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 03/12] rcu: add rcu library Paolo Bonzini
2013-05-16 11:46 ` Stefan Hajnoczi
2013-05-17 4:36 ` liu ping fan
2013-05-17 7:08 ` liu ping fan
2013-05-17 7:35 ` Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 04/12] qemu-thread: register threads with RCU Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 05/12] rcu: add call_rcu Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 06/12] rcu: add rcutorture Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 07/12] rcu: allow nested calls to rcu_thread_offline/rcu_thread_online Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 08/12] qemu-thread: report RCU quiescent states Paolo Bonzini
2013-05-16 8:33 ` liu ping fan
2013-05-16 8:43 ` Paolo Bonzini [this message]
2013-05-15 15:48 ` [Qemu-devel] [PATCH 09/12] event loop: " Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 10/12] cpus: " Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 11/12] block: " Paolo Bonzini
2013-05-15 15:48 ` [Qemu-devel] [PATCH 12/12] migration: " Paolo Bonzini
2013-05-15 16:03 ` [Qemu-devel] [RFC PATCH 00/12] RCU implementation for QEMU Peter Maydell
2013-05-15 16:17 ` Paolo Bonzini
2013-05-15 16:16 ` Peter Maydell
2013-05-15 16:19 ` Paolo Bonzini
2013-05-15 19:28 ` Peter Maydell
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