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Groups > linux.kernel > #1399539
| From | Eric Dumazet <eric.dumazet@gmail.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 0/2] net: threadable napi poll loop |
| Date | 2016-05-12 00:00 +0200 |
| Message-ID | <rxKkG-72-11@gated-at.bofh.it> (permalink) |
| References | (2 earlier) <rxmLo-1CV-7@gated-at.bofh.it> <rxn4J-2dm-1@gated-at.bofh.it> <rxotQ-3v7-1@gated-at.bofh.it> <rxoNc-3DI-3@gated-at.bofh.it> <rxwhH-2Pr-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, 2016-05-11 at 08:55 +0200, Peter Zijlstra wrote:
> On Tue, May 10, 2016 at 03:51:37PM -0700, Eric Dumazet wrote:
> > diff --git a/kernel/softirq.c b/kernel/softirq.c
> > index 17caf4b63342..22463217e3cf 100644
> > --- a/kernel/softirq.c
> > +++ b/kernel/softirq.c
> > @@ -56,6 +56,7 @@ EXPORT_SYMBOL(irq_stat);
> > static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;
> >
> > DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
> > +DEFINE_PER_CPU(bool, ksoftirqd_scheduled);
> >
> > const char * const softirq_to_name[NR_SOFTIRQS] = {
> > "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
> > @@ -73,8 +74,10 @@ static void wakeup_softirqd(void)
> > /* Interrupts are disabled: no need to stop preemption */
> > struct task_struct *tsk = __this_cpu_read(ksoftirqd);
> >
> > - if (tsk && tsk->state != TASK_RUNNING)
> > + if (tsk && tsk->state != TASK_RUNNING) {
> > + __this_cpu_write(ksoftirqd_scheduled, true);
> > wake_up_process(tsk);
>
> Since we're already looking at tsk->state, and the wake_up_process()
> ensures the thing becomes TASK_RUNNING, you could add:
>
> static inline bool ksoftirqd_running(void)
> {
> return __this_cpu_read(ksoftirqd)->state == TASK_RUNNING;
> }
Indeed, and the patch looks quite simple now ;)
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 17caf4b63342d7839528f367b283a386413b0362..23c364485d03618773c385d943c0ef39f5931d09 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -57,6 +57,11 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
+static inline bool ksoftirqd_running(void)
+{
+ return __this_cpu_read(ksoftirqd)->state == TASK_RUNNING;
+}
+
const char * const softirq_to_name[NR_SOFTIRQS] = {
"HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
"TASKLET", "SCHED", "HRTIMER", "RCU"
@@ -313,7 +318,7 @@ asmlinkage __visible void do_softirq(void)
pending = local_softirq_pending();
- if (pending)
+ if (pending && !ksoftirqd_running())
do_softirq_own_stack();
local_irq_restore(flags);
@@ -340,6 +345,9 @@ void irq_enter(void)
static inline void invoke_softirq(void)
{
+ if (ksoftirqd_running())
+ return;
+
if (!force_irqthreads) {
#ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
/*
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[RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-10 16:20 +0200
[RFC PATCH 2/2] net: add sysfs attribute to control napi threaded mode Paolo Abeni <pabeni@redhat.com> - 2016-05-10 16:20 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-10 16:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop David Miller <davem@davemloft.net> - 2016-05-10 18:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-10 18:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-10 22:30 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop David Miller <davem@davemloft.net> - 2016-05-10 22:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop David Miller <davem@davemloft.net> - 2016-05-10 23:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Rik van Riel <riel@redhat.com> - 2016-05-10 23:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Rik van Riel <riel@redhat.com> - 2016-05-10 23:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-10 18:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-10 22:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-10 23:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-10 23:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Rik van Riel <riel@redhat.com> - 2016-05-10 23:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 00:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Rik van Riel <riel@redhat.com> - 2016-05-11 00:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 00:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 00:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 20:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-11 00:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 01:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Peter Zijlstra <peterz@infradead.org> - 2016-05-11 09:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-11 15:20 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-11 16:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Rik van Riel <riel@redhat.com> - 2016-05-11 17:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 18:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-12 00:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-12 22:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-12 22:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-12 23:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-12 23:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-13 19:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-13 19:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-13 19:20 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-13 19:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-16 15:20 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-16 15:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-11 11:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <eric.dumazet@gmail.com> - 2016-05-11 15:10 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-11 15:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-11 15:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-11 16:40 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Eric Dumazet <edumazet@google.com> - 2016-05-11 16:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Hannes Frederic Sowa <hannes@stressinduktion.org> - 2016-05-12 00:50 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Thomas Gleixner <tglx@linutronix.de> - 2016-05-10 18:00 +0200
Re: [RFC PATCH 0/2] net: threadable napi poll loop Paolo Abeni <pabeni@redhat.com> - 2016-05-10 22:50 +0200
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