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Message-ID: <20101019235842.GH2440@sgi.com>
Date: Tue, 19 Oct 2010 16:58:42 -0700
From: Arthur Kepner <akepner@....com>
To: Thomas Gleixner <tglx@...utronix.de>
Cc: "Eric W. Biederman" <ebiederm@...ssion.com>,
LKML <linux-kernel@...r.kernel.org>, x86@...nel.org,
Jesse Barnes <jbarnes@...tuousgeek.org>
Subject: Re: [RFC/PATCHv2] x86/irq: round-robin distribution of irqs to
cpus w/in node
On Sun, Oct 17, 2010 at 12:44:07PM +0200, Thomas Gleixner wrote:
> ....
> Looked a bit deeper into the users. Quite a bunch do
>
> pci_enable_msix();
> request_irqs();
>
> in their probe function. There is no sign of making them per cpu or
> node. mlx4 is one of them. No sign of anything related to nodes or cpus in
> the whole driver.
>
> Even if the driver does not request the irqs from the probe function,
> why does it need to do the msi/msix setup in the probe function at
> all?
>
> Wouldn't it be sufficient to do that at open() right before the
> interrupts are requested.
That's a good point.
> .....
> The fundamental flaw of arch_setup_msi_irqs() is
>
> node = dev_to_node(&dev->dev);
>
> That's the only node information we get. So we put everything on a
> single node.
>
But it's even worse than that, because we put everything on a single
cpu within the node until no vectors are left there, then move on to the
next one...
--
Arthur
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