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| author | Thomas Gleixner <tglx@linutronix.de> | 2021-09-03 18:24:17 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2021-12-10 22:47:38 +0300 |
| commit | 65c7cdedeb3026fabcc967a7aae2f755ad4d0783 (patch) | |
| tree | 4acde9183200a416db3a9ac5008386ef82eb3065 /kernel/irq/manage.c | |
| parent | 4946f15e8c334840bf277a0bf924371eae120fcd (diff) | |
| download | linux-65c7cdedeb3026fabcc967a7aae2f755ad4d0783.tar.xz | |
genirq: Provide new interfaces for affinity hints
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 <tglx@linutronix.de>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
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
Diffstat (limited to 'kernel/irq/manage.c')
| -rw-r--r-- | kernel/irq/manage.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 7405e384e5ed..f23ffd30385b 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -486,7 +486,8 @@ int irq_force_affinity(unsigned int irq, const struct cpumask *cpumask) } EXPORT_SYMBOL_GPL(irq_force_affinity); -int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) +int __irq_apply_affinity_hint(unsigned int irq, const struct cpumask *m, + bool setaffinity) { unsigned long flags; struct irq_desc *desc = irq_get_desc_lock(irq, &flags, IRQ_GET_DESC_CHECK_GLOBAL); @@ -495,12 +496,11 @@ int irq_set_affinity_hint(unsigned int irq, const struct cpumask *m) return -EINVAL; desc->affinity_hint = m; irq_put_desc_unlock(desc, flags); - /* set the initial affinity to prevent every interrupt being on CPU0 */ - if (m) + if (m && setaffinity) __irq_set_affinity(irq, m, false); return 0; } -EXPORT_SYMBOL_GPL(irq_set_affinity_hint); +EXPORT_SYMBOL_GPL(__irq_apply_affinity_hint); static void irq_affinity_notify(struct work_struct *work) { |