* Re: [PATCH] clear irq pending when bypassing it [not found] <20090430161506.GA2636@typhoon.ccur.com> @ 2009-04-30 16:49 ` Eric W. Biederman 2009-04-30 18:00 ` Joe Korty 0 siblings, 1 reply; 3+ messages in thread From: Eric W. Biederman @ 2009-04-30 16:49 UTC (permalink / raw) To: Joe Korty; +Cc: venkatesh.pallipadi, mingo, linux-kernel Joe Korty <jak@typhoon.ccur.com> writes: > IRQ_MOVE_PENDING must be cleared whenever it is bypassed. > > Otherwise, we risk an old, pending affinity change > overtaking and erasing a more recent affinity change that > had been directly applied (eg, IRQ_MOVE_PCNTXT mode). When can this happen? Eric ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] clear irq pending when bypassing it 2009-04-30 16:49 ` [PATCH] clear irq pending when bypassing it Eric W. Biederman @ 2009-04-30 18:00 ` Joe Korty 2009-04-30 18:43 ` Eric W. Biederman 0 siblings, 1 reply; 3+ messages in thread From: Joe Korty @ 2009-04-30 18:00 UTC (permalink / raw) To: Eric W. Biederman Cc: venkatesh.pallipadi@intel.com, mingo@elte.hu, linux-kernel@vger.kernel.org On Thu, Apr 30, 2009 at 12:49:39PM -0400, Eric W. Biederman wrote: > Joe Korty <jak@typhoon.ccur.com> writes: > > > IRQ_MOVE_PENDING must be cleared whenever it is bypassed. > > > > Otherwise, we risk an old, pending affinity change > > overtaking and erasing a more recent affinity change that > > had been directly applied (eg, IRQ_MOVE_PCNTXT mode). > > When can this happen? Probably doesn't happen. AFAIK, each IRQ is either fully MSI or non-MSI. The MSI IRQs will always use IRQ_MOVE_PCNTXT and the non-MSI's will never use IRQ_MOVE_PCNTXT. Thus no collision. It could only happen if it was possible for a MSI and non-MSI device to share an IRQ. Joe ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] clear irq pending when bypassing it 2009-04-30 18:00 ` Joe Korty @ 2009-04-30 18:43 ` Eric W. Biederman 0 siblings, 0 replies; 3+ messages in thread From: Eric W. Biederman @ 2009-04-30 18:43 UTC (permalink / raw) To: Joe Korty Cc: venkatesh.pallipadi@intel.com, mingo@elte.hu, linux-kernel@vger.kernel.org Joe Korty <joe.korty@ccur.com> writes: > On Thu, Apr 30, 2009 at 12:49:39PM -0400, Eric W. Biederman wrote: >> Joe Korty <jak@typhoon.ccur.com> writes: >> >> > IRQ_MOVE_PENDING must be cleared whenever it is bypassed. >> > >> > Otherwise, we risk an old, pending affinity change >> > overtaking and erasing a more recent affinity change that >> > had been directly applied (eg, IRQ_MOVE_PCNTXT mode). >> >> When can this happen? > > Probably doesn't happen. AFAIK, each IRQ is either fully MSI > or non-MSI. The MSI IRQs will always use IRQ_MOVE_PCNTXT and > the non-MSI's will never use IRQ_MOVE_PCNTXT. Thus no collision. > > It could only happen if it was possible for a MSI and non-MSI > device to share an IRQ. Ok. I thought you might have seen something. It doesn't happen and it can't happen, making your patch wrong. Eric ^ permalink raw reply [flat|nested] 3+ messages in thread
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2009-04-30 16:49 ` [PATCH] clear irq pending when bypassing it Eric W. Biederman
2009-04-30 18:00 ` Joe Korty
2009-04-30 18:43 ` Eric W. Biederman
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