From 43ba2237281a59b40ea2393da9e89ea3a68de2a5 Mon Sep 17 00:00:00 2001 From: Max Filippov Date: Fri, 9 Jul 2021 04:13:23 -0700 Subject: [PATCH] xtensa: add fairness to IRQ handling Track which IRQs have been served at each level to make sure that no IRQ is served more than once while other IRQs at the same level are pending. Signed-off-by: Max Filippov --- arch/xtensa/kernel/traps.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c index efc3a29..874b6ef 100644 --- a/arch/xtensa/kernel/traps.c +++ b/arch/xtensa/kernel/traps.c @@ -268,6 +268,7 @@ void do_interrupt(struct pt_regs *regs) XCHAL_INTLEVEL7_MASK, }; struct pt_regs *old_regs; + unsigned unhandled = ~0u; trace_hardirqs_off(); @@ -283,6 +284,10 @@ void do_interrupt(struct pt_regs *regs) for (level = LOCKLEVEL; level > 0; --level) { if (int_at_level & int_level_mask[level]) { int_at_level &= int_level_mask[level]; + if (int_at_level & unhandled) + int_at_level &= unhandled; + else + unhandled |= int_level_mask[level]; break; } } @@ -290,6 +295,8 @@ void do_interrupt(struct pt_regs *regs) if (level == 0) break; + /* clear lowest pending irq in the unhandled mask */ + unhandled ^= (int_at_level & -int_at_level); do_IRQ(__ffs(int_at_level), regs); } -- 2.7.4