linux-kernel - Re: [PATCH v4 -tip 3/3] 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: <50BC796A.8040803@pobox.com>
Date:	Mon, 03 Dec 2012 05:05:30 -0500
From:	Jeff Garzik <jgarzik@...ox.com>
To:	Alexander Gordeev <agordeev@...hat.com>
CC:	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	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,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 -tip 3/3] AHCI: Support multiple MSIs

On 11/19/2012 10:02 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    |   93 +++++++++++++++++++++++++++++++++++++--
>   drivers/ata/ahci.h    |    6 +++
>   drivers/ata/libahci.c |  118 ++++++++++++++++++++++++++++++++++++++++++++++---
>   3 files changed, 207 insertions(+), 10 deletions(-)

Acked-by: Jeff Garzik <jgarzik@...hat.com>



--
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/