From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: "Huangweidong (C)" <weidong.huang@huawei.com>,
"gleb@redhat.com" <gleb@redhat.com>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"Gonglei (Arei)" <arei.gonglei@huawei.com>,
"avi.kivity@gmail.com" <avi.kivity@gmail.com>,
"Herongguang (Stephen)" <herongguang.he@huawei.com>
Subject: Re: [Qemu-devel] [RFC] vhost: Can we change synchronize_rcu to call_rcu in vhost_set_memory() in vhost kernel module?
Date: Mon, 12 May 2014 12:14:25 +0200 [thread overview]
Message-ID: <53709F01.8090204@redhat.com> (raw)
In-Reply-To: <20140512100814.GA15514@redhat.com>
Il 12/05/2014 12:08, Michael S. Tsirkin ha scritto:
> On Mon, May 12, 2014 at 11:57:32AM +0200, Paolo Bonzini wrote:
>> Perhaps we can check for cases where only the address is changing,
>> and poke at an existing struct kvm_kernel_irq_routing_entry without
>> doing any RCU synchronization?
>
> I suspect interrupts can get lost then: e.g. if address didn't match any
> cpus, now it matches some. No?
Can you explain the problem more verbosely? :)
Multiple writers would still be protected by the mutex, so you cannot
have an "in-place update" writer racing with a "copy the array" writer.
Paolo
next prev parent reply other threads:[~2014-05-12 10:14 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-09 1:57 [Qemu-devel] [RFC] vhost: Can we change synchronize_rcu to call_rcu in vhost_set_memory() in vhost kernel module? Gonglei (Arei)
2014-05-09 8:14 ` Paolo Bonzini
2014-05-09 9:04 ` Gonglei (Arei)
2014-05-09 9:53 ` Paolo Bonzini
2014-05-12 9:28 ` Gonglei (Arei)
2014-05-12 9:57 ` Paolo Bonzini
2014-05-12 10:08 ` Michael S. Tsirkin
2014-05-12 10:14 ` Paolo Bonzini [this message]
2014-05-12 10:18 ` Michael S. Tsirkin
2014-05-12 10:25 ` Paolo Bonzini
2014-05-12 11:07 ` Michael S. Tsirkin
2014-05-12 11:46 ` Paolo Bonzini
2014-05-12 12:12 ` Michael S. Tsirkin
2014-05-12 12:46 ` Paolo Bonzini
2014-05-12 12:53 ` Michael S. Tsirkin
2014-05-12 13:02 ` Paolo Bonzini
2014-05-12 10:30 ` Michael S. Tsirkin
2014-05-13 7:03 ` Gonglei (Arei)
2014-05-13 8:21 ` Michael S. Tsirkin
2014-05-13 7:01 ` Gonglei (Arei)
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