|
xen-devel
[Xen-devel] Re: [PATCH 09/14] xen/pvticketlock: Xen implementation for P
|
To: |
Jan Beulich <JBeulich@xxxxxxxxxx> |
|
Subject: |
[Xen-devel] Re: [PATCH 09/14] xen/pvticketlock: Xen implementation for PV ticket locks |
|
From: |
Jeremy Fitzhardinge <jeremy@xxxxxxxx> |
|
Date: |
Wed, 17 Nov 2010 00:52:55 -0800 |
|
Cc: |
Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>, Nick Piggin <npiggin@xxxxxxxxx>, Peter Zijlstra <peterz@xxxxxxxxxxxxx>, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>, Eric Dumazet <dada1@xxxxxxxxxxxxx>, Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Avi Kivity <avi@xxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, xiyou.wangcong@xxxxxxxxx, Linux Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx> |
|
Delivery-date: |
Wed, 17 Nov 2010 00:54:23 -0800 |
|
Envelope-to: |
www-data@xxxxxxxxxxxxxxxxxxx |
|
In-reply-to: |
<4CE39C3C0200007800022AE2@xxxxxxxxxxxxxxxxxx> |
|
List-help: |
<mailto:xen-devel-request@lists.xensource.com?subject=help> |
|
List-id: |
Xen developer discussion <xen-devel.lists.xensource.com> |
|
List-post: |
<mailto:xen-devel@lists.xensource.com> |
|
List-subscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe> |
|
List-unsubscribe: |
<http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe> |
|
References: |
<cover.1289940821.git.jeremy.fitzhardinge@xxxxxxxxxx><cover.1289940821.git.jeremy.fitzhardinge@xxxxxxxxxx> <aa32da076143b8e13c23c1f589d7e6cbedb22907.1289940821.git.jeremy.fitzhardinge@xxxxxxxxxx> <4CE39C3C0200007800022AE2@xxxxxxxxxxxxxxxxxx> |
|
Sender: |
xen-devel-bounces@xxxxxxxxxxxxxxxxxxx |
|
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.12) Gecko/20101027 Fedora/3.1.6-1.fc13 Lightning/1.0b3pre Thunderbird/3.1.6 |
On 11/17/2010 12:11 AM, Jan Beulich wrote:
>>>> On 16.11.10 at 22:08, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
>> +static void xen_lock_spinning(struct arch_spinlock *lock, unsigned want)
>> {
>> - struct xen_spinlock *xl = (struct xen_spinlock *)lock;
>> - struct xen_spinlock *prev;
>> int irq = __get_cpu_var(lock_kicker_irq);
>> - int ret;
>> + struct xen_lock_waiting *w = &__get_cpu_var(lock_waiting);
>> + int cpu = smp_processor_id();
>> u64 start;
>>
>> /* If kicker interrupts not initialized yet, just spin */
>> if (irq == -1)
>> - return 0;
>> + return;
>>
>> start = spin_time_start();
>>
>> - /* announce we're spinning */
>> - prev = spinning_lock(xl);
>> + w->want = want;
>> + w->lock = lock;
>> +
>> + /* This uses set_bit, which atomic and therefore a barrier */
>> + cpumask_set_cpu(cpu, &waiting_cpus);
> Since you don't allow nesting, don't you need to disable
> interrupts before you touch per-CPU state?
Yes, I think you're right - interrupts need to be disabled for the bulk
of this function.
J
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
|
|
|
Home