This is the optimization that I promised back in
https://lore.kernel.org/lkml/[email protected]/
and got back around to cleaning up. To quote that cover letter:
"A further optimization is to take advantage of the fact that multiple
IRQs can be claimed at once. This allows removing the mask operations
for oneshot IRQs -- i.e. the combination of IRQCHIP_ONESHOT_SAFE and
IRQCHIP_EOI_THREADED, which is not currently supported."
Or in other words, we reuse the oneshot infrastructure for EOIs instead
of masking.
There a a few functions/variables that probably should be renamed now
that I have muddied what "oneshot" means. I elected not to do that in
this version to avoid distracting from the functional changes.
Samuel Holland (3):
genirq: Simplify cond_unmask_eoi_irq()
genirq: Add support for oneshot-safe threaded EOIs
irqchip/sifive-plic: Enable oneshot-safe threaded EOIs
drivers/irqchip/irq-sifive-plic.c | 2 ++
kernel/irq/chip.c | 21 ++++++++++++---------
kernel/irq/manage.c | 15 ++++++++++-----
3 files changed, 24 insertions(+), 14 deletions(-)
--
2.37.4
This defers the EOI until the IRQ thread has finished, avoiding the need
to mask the IRQ while the thread is pending.
Signed-off-by: Samuel Holland <[email protected]>
---
drivers/irqchip/irq-sifive-plic.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index ff47bd0dec45..d8fc3354b38c 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -203,6 +203,8 @@ static struct irq_chip plic_chip = {
#endif
.irq_set_type = plic_irq_set_type,
.flags = IRQCHIP_SKIP_SET_WAKE |
+ IRQCHIP_ONESHOT_SAFE |
+ IRQCHIP_EOI_THREADED |
IRQCHIP_AFFINITY_PRE_STARTUP,
};
--
2.37.4