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[PATCH 0/2] cpumask fallout: Initialize irq_default_affinity earlier et

To: Andrew Morton <>, Rusty Russell <>, Linus Torvalds <>
Subject: [PATCH 0/2] cpumask fallout: Initialize irq_default_affinity earlier et al. (v3)
From: David Daney <>
Date: Tue, 13 Jan 2009 10:45:39 -0800
Cc: Linux Kernel Mailing List <>, linux-mips <>, Mike Travis <>
Original-recipient: rfc822;
User-agent: Thunderbird (X11/20090105)
Now that mips/OCTEON support has been merged, this patch set has slightly more urgency.

The interrupt affinity on OCTEON is determined by irq_default_affinity,
because that is what the code in kernel/irq/manage.c uses to set affinity. Since for the majority of devices (Serial, Compact Flash,
Network...) we want interrupts to be handled on a single CPU, we set
irq_default_affinity to the boot CPU in init_IRQ().  The problem we
have is that with the new cpumask infrastructure, irq_default_affinity
is being initialized in core_initcall which undoes our initialization.

As I said in 2/2:

    Move the initialization of irq_default_affinity to early_irq_init
    as core_initcall is too late.

    irq_default_affinity can be used in init_IRQ and potentially timer
    and SMP init as well.  All of these happen before core_initcall.
    Moving the initialization to early_irq_init ensures that it is
    initialized before it is used.

Mike Travis pointed out that irq_default_affinity depends on
CONFIG_GENERIC_HARDIRQS in addition to CONFIG_SMP.  So to make things
consistent, I added 1/2 so that the irq_*_affinity functions and
irq_default_affinity are defined for the same conditions that they are

I Took Linus' suggestion to move init_irq_default_affinity over to
kernel/irq/handle.c, however due to the way that cpumask_*() are
defined, it is still necessary to have the ugly ifdefs, but now they
are localized to init_irq_default_affinity.

Mike Travis also suggested that alloc_bootmem_cpumask_var() be used in
preference to alloc_cpumask_var, so I incorporated that suggestion as

I tested both with and without CONFIG_SMP, on mips/cavium_octeon, Mike
tested a similar(but not identical patch) on x86_64.

Changes from v2 of this set are just a small rearrangement of the
#ifdefs suggested by Ihar Hrachyshka that make the code look a bit

I will reply with the two patches.

David Daney (2):
  Make irq_*_affinity depend on CONFIG_GENERIC_HARDIRQS too.
  cpumask fallout: Initialize irq_default_affinity earlier (v3).

 kernel/irq/handle.c |   16 ++++++++++++++++
 kernel/irq/manage.c |   10 +---------
 2 files changed, 17 insertions(+), 9 deletions(-)

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