user/sven/linux.git/include/linux/interrupt.h, branch v5.17.1

genirq: Provide new interfaces for affinity hints

2021-12-10T19:47:38Z

The discussion about removing the side effect of irq_set_affinity_hint() of actually applying the cpumask (if not NULL) as affinity to the interrupt, unearthed a few unpleasantries: 1) The modular perf drivers rely on the current behaviour for the very wrong reasons. 2) While none of the other drivers prevents user space from changing the affinity, a cursorily inspection shows that there are at least expectations in some drivers. #1 needs to be cleaned up anyway, so that's not a problem #2 might result in subtle regressions especially when irqbalanced (which nowadays ignores the affinity hint) is disabled. Provide new interfaces: irq_update_affinity_hint() - Only sets the affinity hint pointer irq_set_affinity_and_hint() - Set the pointer and apply the affinity to the interrupt Make irq_set_affinity_hint() a wrapper around irq_apply_affinity_hint() and document it to be phased out. Signed-off-by: Thomas Gleixner Signed-off-by: Nitesh Narayan Lal Signed-off-by: Thomas Gleixner Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20210501021832.743094-1-jesse.brandeburg@intel.com Link: https://lore.kernel.org/r/20210903152430.244937-2-nitesh@redhat.com

genirq: Change force_irqthreads to a static key

2021-08-10T20:50:07Z

With CONFIG_IRQ_FORCED_THREADING=y, testing the boolean force_irqthreads could incur a cache line miss in invoke_softirq() and other places. Replace the test with a static key to avoid the potential cache miss. [ tglx: Dropped the IDE part, removed the export and updated blk-mq ] Suggested-by: Eric Dumazet Signed-off-by: Tanner Love Signed-off-by: Thomas Gleixner Reviewed-by: Eric Dumazet Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20210602180338.3324213-1-tannerlove.kernel@gmail.com

Merge branch 'irq/affinity' into irq/core

2021-05-19T09:04:47Z

Merge the export of irq_set_affinity() which is a standalone commit so it can be pulled into other trees.

genirq: Export affinity setter for modules

2021-05-19T09:01:51Z

Perf modules abuse irq_set_affinity_hint() to set the affinity of system PMU interrupts just because irq_set_affinity() was not exported. The fact that irq_set_affinity_hint() actually sets the affinity is a non-documented side effect and the name is clearly saying it's a hint. To clean this up, export the real affinity setter. Signed-off-by: Thomas Gleixner Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20210518093117.968251441@linutronix.de

genirq: Add a IRQF_NO_DEBUG flag

2021-05-17T18:01:35Z

The whole call to note_interrupt() can be avoided or return early when interrupts would be marked accordingly. For IPI handlers which always return HANDLED the whole procedure is pretty pointless to begin with. Add a IRQF_NO_DEBUG flag and mark the interrupt accordingly if supplied when the interrupt is requested. When noirqdebug is set on the kernel commandline, then the interrupt is marked unconditionally so that there is only one condition in the hotpath to evaluate. [ clg: Add changelog ] Signed-off-by: Thomas Gleixner Signed-off-by: Cédric Le Goater Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/7a8ad02f-63a8-c1aa-fdd1-39d973593d02@kaod.org

tasklets: Switch tasklet_disable() to the sleep wait variant

2021-03-17T15:34:07Z

-- NOT FOR IMMEDIATE MERGING -- Now that all users of tasklet_disable() are invoked from sleepable context, convert it to use tasklet_unlock_wait() which might sleep. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210309084242.726452321@linutronix.de

tasklets: Prevent tasklet_unlock_spin_wait() deadlock on RT

2021-03-17T15:33:57Z

tasklet_unlock_spin_wait() spin waits for the TASKLET_STATE_SCHED bit in the tasklet state to be cleared. This works on !RT nicely because the corresponding execution can only happen on a different CPU. On RT softirq processing is preemptible, therefore a task preempting the softirq processing thread can spin forever. Prevent this by invoking local_bh_disable()/enable() inside the loop. In case that the softirq processing thread was preempted by the current task, current will block on the local lock which yields the CPU to the preempted softirq processing thread. If the tasklet is processed on a different CPU then the local_bh_disable()/enable() pair is just a waste of processor cycles. Signed-off-by: Thomas Gleixner Tested-by: Sebastian Andrzej Siewior Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210309084241.988908275@linutronix.de

tasklets: Replace spin wait in tasklet_unlock_wait()

2021-03-17T15:33:55Z

tasklet_unlock_wait() spin waits for TASKLET_STATE_RUN to be cleared. This is wasting CPU cycles in a tight loop which is especially painful in a guest when the CPU running the tasklet is scheduled out. tasklet_unlock_wait() is invoked from tasklet_kill() which is used in teardown paths and not performance critical at all. Replace the spin wait with wait_var_event(). There are no users of tasklet_unlock_wait() which are invoked from atomic contexts. The usage in tasklet_disable() has been replaced temporarily with the spin waiting variant until the atomic users are fixed up and will be converted to the sleep wait variant later. Signed-off-by: Peter Zijlstra Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210309084241.783936921@linutronix.de

tasklets: Use spin wait in tasklet_disable() temporarily

2021-03-17T15:33:54Z

To ease the transition use spin waiting in tasklet_disable() until all usage sites from atomic context have been cleaned up. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210309084241.685352806@linutronix.de

tasklets: Provide tasklet_disable_in_atomic()

2021-03-17T15:33:52Z

Replacing the spin wait loops in tasklet_unlock_wait() with wait_var_event() is not possible as a handful of tasklet_disable() invocations are happening in atomic context. All other invocations are in teardown paths which can sleep. Provide tasklet_disable_in_atomic() and tasklet_unlock_spin_wait() to convert the few atomic use cases over, which allows to change tasklet_disable() and tasklet_unlock_wait() in a later step. Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210309084241.563164193@linutronix.de