From: Avi Kivity <avi@redhat.com>
To: liu ping fan <qemulist@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org,
Stefan Hajnoczi <stefanha@gmail.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: [PATCH 1/5] qom: adopt rwlock to protect accessing dev from removing it
Date: Thu, 26 Jul 2012 16:46:42 +0300 [thread overview]
Message-ID: <50114A42.2050702@redhat.com> (raw)
In-Reply-To: <CAJnKYQmJMaKycc1Xq4W_W1VOzEbvoDwLa8f1O_FJRqvQbuhh7w@mail.gmail.com>
On 07/26/2012 04:21 PM, liu ping fan wrote:
> On Thu, Jul 26, 2012 at 9:15 PM, Avi Kivity <avi@redhat.com> wrote:
>> On 07/26/2012 04:14 PM, liu ping fan wrote:
>>>>
>>>> From the description above, I don't see why it can't be a mutex.
>>>>
>>> Searching in the device tree (or MemoryRegion view) can be often in
>>> parallel, especially in mmio-dispatch code path
>>
>> In mmio dispatch we have a pointer to the object, we don't need to
>> search anything. Is device tree search a hot path?
>>
> I think, we need lock to protect searching --phys_page_find() from
> deleter--DeviceClass:unmap, so rwlock?
Better a lock on phys_map (because it is easily replaced by rcu, later).
I think phys_map is also better isolated, so it will be easier to find
all the placed that need protection and to avoid deadlock.
--
error compiling committee.c: too many arguments to function
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: liu ping fan <qemulist@gmail.com>
Cc: kvm@vger.kernel.org, Stefan Hajnoczi <stefanha@gmail.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel@nongnu.org, Anthony Liguori <anthony@codemonkey.ws>,
Jan Kiszka <jan.kiszka@siemens.com>,
Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 1/5] qom: adopt rwlock to protect accessing dev from removing it
Date: Thu, 26 Jul 2012 16:46:42 +0300 [thread overview]
Message-ID: <50114A42.2050702@redhat.com> (raw)
In-Reply-To: <CAJnKYQmJMaKycc1Xq4W_W1VOzEbvoDwLa8f1O_FJRqvQbuhh7w@mail.gmail.com>
On 07/26/2012 04:21 PM, liu ping fan wrote:
> On Thu, Jul 26, 2012 at 9:15 PM, Avi Kivity <avi@redhat.com> wrote:
>> On 07/26/2012 04:14 PM, liu ping fan wrote:
>>>>
>>>> From the description above, I don't see why it can't be a mutex.
>>>>
>>> Searching in the device tree (or MemoryRegion view) can be often in
>>> parallel, especially in mmio-dispatch code path
>>
>> In mmio dispatch we have a pointer to the object, we don't need to
>> search anything. Is device tree search a hot path?
>>
> I think, we need lock to protect searching --phys_page_find() from
> deleter--DeviceClass:unmap, so rwlock?
Better a lock on phys_map (because it is easily replaced by rcu, later).
I think phys_map is also better isolated, so it will be easier to find
all the placed that need protection and to avoid deadlock.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2012-07-26 13:46 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-25 3:31 [PATCH 0/5] prepare unplug out of protection of global lock Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 3:31 ` [PATCH 1/5] qom: adopt rwlock to protect accessing dev from removing it Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 9:08 ` Paolo Bonzini
2012-07-25 9:08 ` [Qemu-devel] " Paolo Bonzini
2012-07-26 12:56 ` liu ping fan
2012-07-26 12:56 ` [Qemu-devel] " liu ping fan
2012-07-26 13:00 ` Avi Kivity
2012-07-26 13:00 ` [Qemu-devel] " Avi Kivity
2012-07-26 13:14 ` liu ping fan
2012-07-26 13:14 ` [Qemu-devel] " liu ping fan
2012-07-26 13:15 ` Avi Kivity
2012-07-26 13:15 ` [Qemu-devel] " Avi Kivity
2012-07-26 13:21 ` liu ping fan
2012-07-26 13:21 ` [Qemu-devel] " liu ping fan
2012-07-26 13:46 ` Avi Kivity [this message]
2012-07-26 13:46 ` Avi Kivity
2012-07-25 3:31 ` [PATCH 2/5] exec.c: use refcnt to protect device during dispatching Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 7:43 ` Stefan Hajnoczi
2012-07-25 7:43 ` [Qemu-devel] " Stefan Hajnoczi
2012-07-25 8:12 ` liu ping fan
2012-07-25 8:12 ` [Qemu-devel] " liu ping fan
2012-07-25 9:18 ` Paolo Bonzini
2012-07-25 9:18 ` [Qemu-devel] " Paolo Bonzini
2012-07-26 13:00 ` liu ping fan
2012-07-26 13:00 ` [Qemu-devel] " liu ping fan
2012-07-25 10:58 ` Avi Kivity
2012-07-25 10:58 ` [Qemu-devel] " Avi Kivity
2012-07-25 12:27 ` Avi Kivity
2012-07-25 12:27 ` [Qemu-devel] " Avi Kivity
2012-07-26 13:06 ` liu ping fan
2012-07-26 13:06 ` [Qemu-devel] " liu ping fan
2012-07-26 13:13 ` Avi Kivity
2012-07-26 13:13 ` [Qemu-devel] " Avi Kivity
2012-07-25 3:31 ` [PATCH 3/5] hotplug: introduce qdev_unplug_ack() to remove device from views Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 10:58 ` Avi Kivity
2012-07-25 10:58 ` [Qemu-devel] " Avi Kivity
2012-07-25 3:31 ` [PATCH 4/5] qom: delay DeviceState's reclaim to main-loop Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 7:03 ` Stefan Hajnoczi
2012-07-25 7:03 ` [Qemu-devel] " Stefan Hajnoczi
2012-07-25 7:37 ` Paolo Bonzini
2012-07-25 7:37 ` [Qemu-devel] " Paolo Bonzini
2012-07-25 8:16 ` liu ping fan
2012-07-25 8:16 ` [Qemu-devel] " liu ping fan
2012-07-25 8:22 ` Paolo Bonzini
2012-07-25 8:22 ` [Qemu-devel] " Paolo Bonzini
2012-07-25 8:17 ` liu ping fan
2012-07-25 8:17 ` [Qemu-devel] " liu ping fan
2012-07-25 3:31 ` [PATCH 5/5] e1000: using new interface--unmap to unplug Liu Ping Fan
2012-07-25 3:31 ` [Qemu-devel] " Liu Ping Fan
2012-07-25 7:12 ` Stefan Hajnoczi
2012-07-25 7:12 ` [Qemu-devel] " Stefan Hajnoczi
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