On 2023/5/5 20:10, Eric Dumazet wrote:
On Fri, May 5, 2023 at 1:24 PM Liu Jian <liujian56@xxxxxxxxxx> wrote:
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Allow terminating the softirq processing loop without finishing the
vectors.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Liu Jian <liujian56@xxxxxxxxxx>
---
kernel/softirq.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 48a81d8ae49a..e2cad5d108c8 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -582,6 +582,9 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
prev_count, preempt_count());
preempt_count_set(prev_count);
}
+
+ if (pending && __softirq_needs_break(start))
+ break;
This means that some softirq may starve, because
for_each_set_bit(vec_nr, &pending, NR_SOFTIRQS)
Always iterate using the same order (of bits)
Yes, we need to record the softirq that is not executed and continue
next time. I will fix it in next version.
Thanks.
}
if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
@@ -590,13 +593,14 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
local_irq_disable();
- pending = local_softirq_pending();
- if (pending) {
- if (!__softirq_needs_break(start) && --max_restart)
- goto restart;
+ if (pending)
+ or_softirq_pending(pending);
+ else if ((pending = local_softirq_pending()) &&
+ !__softirq_needs_break(start) &&
+ --max_restart)
+ goto restart;
- wakeup_softirqd();
- }
+ wakeup_softirqd();
account_softirq_exit(current);
lockdep_softirq_end(in_hardirq);
--
2.34.1
