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Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000 |
Date: |
Thu, 25 Oct 2012 18:41:04 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2012-10-25 18:23, Avi Kivity wrote:
> On 10/25/2012 03:34 PM, Jan Kiszka wrote:
>
>>>> Second, it clearly shows that we need to address lock-less IRQ delivery.
>>>> Almost nothing is won if we have to take the global lock again to push
>>>> an IRQ event to the guest. I'm repeating myself, but the problem to be
>>>> solved here is almost identical to fast IRQ delivery for assigned
>>>> devices (which we only address pretty ad-hoc for PCI so far).
>>>>
>>> Interesting, could you show me more detail about it, so I can google...
>>
>> No need to look that far, just grep for pci_device_route_intx_to_irq,
>> pci_device_set_intx_routing_notifier and related functions in the code.
>
> We can address it in the same way the memory core supports concurrency,
> by copying dispatch information into rcu or lock protected data structures.
>
> But I really hope we can avoid doing it now.
I doubt so as the alternative is taking the BQL while (still) holding
the device lock. But that creates ABBA risks.
Jan
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, (continued)
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Jan Kiszka, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Jan Kiszka, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Jan Kiszka, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, liu ping fan, 2012/10/29
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, liu ping fan, 2012/10/24
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Jan Kiszka, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000,
Jan Kiszka <=
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, liu ping fan, 2012/10/29
- Re: [Qemu-devel] [patch v4 12/16] e1000: apply fine lock on e1000, Jan Kiszka, 2012/10/31
[Qemu-devel] [patch v4 03/16] hotplug: introduce qdev_unplug_complete() to remove device from views, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 01/16] atomic: introduce atomic operations, Liu Ping Fan, 2012/10/22
[Qemu-devel] [patch v4 13/16] e1000: add busy flag to anti broken device state, Liu Ping Fan, 2012/10/22