From: Paolo Bonzini <pbonzini@redhat.com>
To: Wen Congyang <wency@cn.fujitsu.com>,
Wen Congyang <ghostwcy@gmail.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] rcu: actually register threads that have RCU read-side critical sections
Date: Fri, 24 Jul 2015 08:22:45 +0200 [thread overview]
Message-ID: <55B1D9B5.90901@redhat.com> (raw)
In-Reply-To: <55B1D380.7020300@cn.fujitsu.com>
On 24/07/2015 07:56, Wen Congyang wrote:
> @@ -115,9 +116,12 @@ static void wait_for_readers(void)
> }
>
> /* Wait for one thread to report a quiescent state and
> - * try again.
> + * try again. Release rcu_gp_lock, so rcu_(un)register_thread()
> + * doesn't wait too much time.
> */
> + qemu_mutex_unlock(&rcu_gp_lock);
> qemu_event_wait(&rcu_gp_event);
> + qemu_mutex_lock(&rcu_gp_lock);
> }
>
So in this case rcu_unregister_thread could actually remove the node
from synchronize_rcu's qsreaders, not just from registry. That's a bit
tricky, but it should work. Please add a comment, however.
Also, please rename "rcu_gp_lock" as well to rcu_registry_lock. We'll
get the patches in QEMU 2.5.
Paolo
next prev parent reply other threads:[~2015-07-24 6:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-22 14:18 [Qemu-devel] [PATCH] rcu: actually register threads that have RCU read-side critical sections Paolo Bonzini
2015-07-23 2:56 ` Wen Congyang
2015-07-23 5:35 ` Paolo Bonzini
2015-07-23 10:30 ` Christian Borntraeger
2015-07-23 10:42 ` Paolo Bonzini
2015-07-23 11:04 ` Wen Congyang
2015-07-23 11:08 ` Paolo Bonzini
2015-07-23 12:59 ` Wen Congyang
2015-07-23 16:58 ` Paolo Bonzini
2015-07-24 3:55 ` Wen Congyang
2015-07-24 5:56 ` Wen Congyang
2015-07-24 6:22 ` Paolo Bonzini [this message]
2015-07-24 6:30 ` Wen Congyang
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