Subject: softirq: Rewrite softirq processing loop From: Peter Zijlstra Date: Fri Sep 11 17:00:03 CEST 2020 Simplify the softirq processing loop by using the bitmap APIs Signed-off-by: Peter Zijlstra (Intel) --- kernel/softirq.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -258,9 +258,9 @@ asmlinkage __visible void __softirq_entr unsigned long old_flags = current->flags; int max_restart = MAX_SOFTIRQ_RESTART; struct softirq_action *h; + unsigned long pending; + unsigned int vec_nr; bool in_hardirq; - __u32 pending; - int softirq_bit; /* * Mask out PF_MEMALLOC as the current task context is borrowed for the @@ -281,15 +281,13 @@ asmlinkage __visible void __softirq_entr local_irq_enable(); - h = softirq_vec; + for_each_set_bit(vec_nr, &pending, NR_SOFTIRQS) { + unsigned int prev_count; - while ((softirq_bit = ffs(pending))) { - unsigned int vec_nr; - int prev_count; + __clear_bit(vec_nr, &pending); - h += softirq_bit - 1; + h = softirq_vec + vec_nr; - vec_nr = h - softirq_vec; prev_count = preempt_count(); kstat_incr_softirqs_this_cpu(vec_nr); @@ -303,8 +301,6 @@ asmlinkage __visible void __softirq_entr prev_count, preempt_count()); preempt_count_set(prev_count); } - h++; - pending >>= softirq_bit; } if (__this_cpu_read(ksoftirqd) == current)