Re: [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.

On 10/22/06, Eric W. Biederman <[email protected]> wrote:

When I generalized __assign_irq_vector I failed to pay attention
to what happens when you access a per cpu data structure for
a cpu that is not online.   It is an undefined case making any
code that does it have undefined behavior as well.

The code still needs to be able to allocate a vector across cpus
that are not online to properly handle combinations like lowest
priority interrupt delivery and cpu_hotplug.  Not that we can do
that today but the infrastructure shouldn't prevent it.

So this patch updates the places where we touch per cpu data
to only touch online cpus, it makes cpu vector allocation
an atomic operation with respect to cpu hotplug, and it updates
the cpu start code to properly initialize vector_irq so we
don't have inconsistencies.

Signed-off-by: Eric W. Biederman <[email protected]>

Acked-by: Yinghai Lu <[email protected]>
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• References:
  • Re: [PATCH] x86-64: typo in __assign_irq_vector when updating pos for vector and offset
    • From: Muli Ben-Yehuda <[email protected]>
  • Re: [PATCH] x86-64: typo in __assign_irq_vector when updating pos for vector and offset
    • From: [email protected] (Eric W. Biederman)
  • Re: [PATCH] x86-64: typo in __assign_irq_vector when updating pos for vector and offset
    • From: Muli Ben-Yehuda <[email protected]>
  • [PATCH 1/2] x86_64 irq: Simplify the vector allocator.
    • From: [email protected] (Eric W. Biederman)
  • [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.
    • From: [email protected] (Eric W. Biederman)

• Prev by Date: Re: [RFC] cpuset: add interface to isolated cpus
• Next by Date: [PATCH 2.6.19-rc2] net/ipv4/multipath_wrandom.c: check kmalloc() return value.
• Previous by thread: [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.
• Next by thread: Re: [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]