From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [PATCH] posix-aio-compat: fix latency issues
Date: Sat, 13 Aug 2011 20:43:28 -0700 [thread overview]
Message-ID: <4E474460.2060803@redhat.com> (raw)
In-Reply-To: <4E452994.9080805@codemonkey.ws>
On 08/12/2011 06:24 AM, Anthony Liguori wrote:
> On 08/08/2011 06:37 AM, Avi Kivity wrote:
>>
>> +static void spawn_thread_bh_fn(void *opaque)
>> +{
>> + mutex_lock(&lock);
>> + do_spawn_thread();
>> + mutex_unlock(&lock);
>> +}
>
> The locking here is odd. Why not call do_spawn_thread() without the
> lock, and acquire the lock for the section that needs to hold it?
Just the way the code evolved. Note that aio_thread() does need to take
the lock. However, it is indeed cleaner to take the lock when needed
rather than drop it when not.
>
> Otherwise, the logic seems correct to me.
>
> Kevin, could you also take a look at this patch?
Yes please.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Anthony Liguori <anthony@codemonkey.ws>
Cc: Kevin Wolf <kwolf@redhat.com>,
qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH] posix-aio-compat: fix latency issues
Date: Sat, 13 Aug 2011 20:43:28 -0700 [thread overview]
Message-ID: <4E474460.2060803@redhat.com> (raw)
In-Reply-To: <4E452994.9080805@codemonkey.ws>
On 08/12/2011 06:24 AM, Anthony Liguori wrote:
> On 08/08/2011 06:37 AM, Avi Kivity wrote:
>>
>> +static void spawn_thread_bh_fn(void *opaque)
>> +{
>> + mutex_lock(&lock);
>> + do_spawn_thread();
>> + mutex_unlock(&lock);
>> +}
>
> The locking here is odd. Why not call do_spawn_thread() without the
> lock, and acquire the lock for the section that needs to hold it?
Just the way the code evolved. Note that aio_thread() does need to take
the lock. However, it is indeed cleaner to take the lock when needed
rather than drop it when not.
>
> Otherwise, the logic seems correct to me.
>
> Kevin, could you also take a look at this patch?
Yes please.
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2011-08-14 3:43 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-08 11:37 [PATCH] posix-aio-compat: fix latency issues Avi Kivity
2011-08-08 11:37 ` [Qemu-devel] " Avi Kivity
2011-08-08 12:34 ` Anthony Liguori
2011-08-08 12:34 ` [Qemu-devel] " Anthony Liguori
2011-08-08 12:42 ` Avi Kivity
2011-08-08 12:49 ` Frediano Ziglio
2011-08-08 12:54 ` Avi Kivity
2011-08-08 12:54 ` [Qemu-devel] " Avi Kivity
2011-08-08 13:21 ` Frediano Ziglio
2011-08-08 13:26 ` Avi Kivity
2011-08-12 13:24 ` Anthony Liguori
2011-08-12 13:24 ` Anthony Liguori
2011-08-14 3:43 ` Avi Kivity [this message]
2011-08-14 3:43 ` Avi Kivity
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