Messages in this thread | | | From | Kumar Gala <> | Subject | Re: [PATCH 1/1] irq: Maintain user set affinity | Date | Thu, 6 Nov 2008 17:23:51 -0600 |
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On Nov 6, 2008, at 3:35 PM, Andrew Morton wrote:
> On Tue, 4 Nov 2008 10:31:05 -0600 (CST) > Kumar Gala <galak@kernel.crashing.org> wrote: > >>> From 819ad3ed4660f4238e053728a8b5aa93d22b13d7 Mon Sep 17 00:00:00 >>> 2001 >> From: Kumar Gala <galak@kernel.crashing.org> >> Date: Tue, 4 Nov 2008 10:13:53 -0600 >> Subject: [PATCH 1/1] irq: Maintain user set affinity >> >> This addresses a regression in that if a user specified an affinity >> for an interrupt that affinity information would get reset between >> a request_irq(), free_irq() and request_irq() for the same irq. >> >> On example of this is bringing up an ethernet interface, taking >> it down and bringing it back up again. >> >> Instead of always using the irq_default_affinity we use the >> previous setting of the IRQs affinity with the assumption that >> at boot the IRQs affinity will be set to irq_default_affinity. >> >> Signed-off-by: Kumar Gala <galak@kernel.crashing.org> >> --- >> kernel/irq/manage.c | 7 +++++-- >> 1 files changed, 5 insertions(+), 2 deletions(-) >> >> diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c >> index c498a1b..ea7d11b 100644 >> --- a/kernel/irq/manage.c >> +++ b/kernel/irq/manage.c >> @@ -115,9 +115,12 @@ int irq_select_affinity(unsigned int irq) >> if (!irq_can_set_affinity(irq)) >> return 0; >> >> - cpus_and(mask, cpu_online_map, irq_default_affinity); >> - >> desc = irq_to_desc(irq); >> + >> + mask = desc->affinity; >> + >> + cpus_and(mask, cpu_online_map, mask); >> + >> desc->affinity = mask; >> desc->chip->set_affinity(irq, mask); >> > > Are you able to identify when this regression occurred? It isn't > immediately obvious to me. > > If the regression is present in 2.6.27 or earlier, do you think we > should backport the fix? If so, a different patch would be needed due > to the presence of > > commit 08678b0841267c1d00d771fe01548d86043d065e > Author: Yinghai Lu <yhlu.kernel@gmail.com> > Date: Tue Aug 19 20:50:05 2008 -0700 > > generic: sparse irqs: use irq_desc() together with dyn_array, > instead of irq_desc[]
It didn't creep in during 2.6.27. I will back port a patch to 2.6.27. Thomas has provided me a better patch that handles a few critical issues that mine doesn't. I'll be testing it this evening and will backport to 2.6.27 if it works out.
- k
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