linux-kernel - Re: [PATCH v3 -tip 5/5] AHCI: Support multiple MSIs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAErSpo5okRNxzRUj1Q8KEJi4WE_e5Aiq7B8Z-beJP=BikxU+6g@mail.gmail.com>
Date:	Mon, 1 Oct 2012 22:21:36 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	Jeff Garzik <jgarzik@...ox.com>
Cc:	Alexander Gordeev <agordeev@...hat.com>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Suresh Siddha <suresh.b.siddha@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Matthew Wilcox <willy@...ux.intel.com>, x86@...nel.org,
	linux-pci@...r.kernel.org, linux-ide@...r.kernel.org
Subject: Re: [PATCH v3 -tip 5/5] AHCI: Support multiple MSIs

On Mon, Oct 1, 2012 at 9:04 PM, Jeff Garzik <jgarzik@...ox.com> wrote:
> On 10/01/2012 04:13 AM, Alexander Gordeev wrote:
>>
>> Take advantage of multiple MSIs implementation on x86 - on systems with
>> IRQ remapping AHCI ports not only get assigned separate MSI vectors -
>> but also separate IRQs. As result, interrupts generated by different
>> ports could be serviced on different CPUs rather than on a single one.
>>
>> In cases when number of allocated MSIs is less than requested the Sharing
>> Last MSI mode does not get used, no matter implemented in hardware or not.
>> Instead, the driver assumes the advantage of multiple MSIs is negated and
>> falls back to the single MSI mode as if MRSM bit was set (some Intel chips
>> implement this strategy anyway - MRSM bit gets set even if the number of
>> allocated MSIs exceeds the number of implemented ports).
>>
>> Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
>> ---
>>   drivers/ata/ahci.c    |   91 ++++++++++++++++++++++++++++++++++++--
>>   drivers/ata/ahci.h    |    6 +++
>>   drivers/ata/libahci.c |  118
>> ++++++++++++++++++++++++++++++++++++++++++++++---
>>   3 files changed, 205 insertions(+), 10 deletions(-)
>
>
> Acked-by: Jeff Garzik <jgarzik@...hat.com>
>
> Normally, this amount of changes would -really- need to go through the
> libata tree.  However, given the amount of dependencies, it either needs a
> merge tree or to go through the PCI tree...?
>
> Any maintainer comments on disposition?

For what it's worth, the bulk of this change is outside PCI, so it
doesn't seem to me like it should go through the PCI tree.  I think I
did ack the part that touched PCI, and there's not much activity in
the PCI MSI area right now, so I'm fine with it going through libata
or whatever people think makes sense.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/