| Message ID | 1397664384.4222.124.camel@edumazet-glaptop2.roam.corp.google.com |
|---|---|
| State | Not Applicable, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, Apr 16, 2014 at 09:06:24AM -0700, Eric Dumazet wrote: > From: Eric Dumazet <edumazet@google.com> > > Calling rcu_bh_qs() after every softirq action is not really needed. > > What RCU needs is at least one rcu_bh_qs() per softirq round to note a > quiescent state was passed for rcu_bh > > Note for Paul and myself : this could be inlined as a single instruction > and avoid smp_processor_id() > (sone this_cpu_write(rcu_bh_data.passed_quiesce, 1)) > > Signed-off-by: Eric Dumazet <edumazet@google.com> Looks plausible -- will give it a go! If nothing breaks, queued for 3.16. Thanx, Paul > --- > kernel/softirq.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/kernel/softirq.c b/kernel/softirq.c > index b50990a5bea0..b9b2d4906848 100644 > --- a/kernel/softirq.c > +++ b/kernel/softirq.c > @@ -232,7 +232,6 @@ asmlinkage void __do_softirq(void) > bool in_hardirq; > __u32 pending; > int softirq_bit; > - int cpu; > > /* > * Mask out PF_MEMALLOC s current task context is borrowed for the > @@ -247,7 +246,6 @@ asmlinkage void __do_softirq(void) > __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET); > in_hardirq = lockdep_softirq_start(); > > - cpu = smp_processor_id(); > restart: > /* Reset the pending bitmask before enabling irqs */ > set_softirq_pending(0); > @@ -276,11 +274,11 @@ restart: > prev_count, preempt_count()); > preempt_count_set(prev_count); > } > - rcu_bh_qs(cpu); > h++; > pending >>= softirq_bit; > } > > + rcu_bh_qs(smp_processor_id()); > local_irq_disable(); > > pending = local_softirq_pending(); > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/kernel/softirq.c b/kernel/softirq.c index b50990a5bea0..b9b2d4906848 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -232,7 +232,6 @@ asmlinkage void __do_softirq(void) bool in_hardirq; __u32 pending; int softirq_bit; - int cpu; /* * Mask out PF_MEMALLOC s current task context is borrowed for the @@ -247,7 +246,6 @@ asmlinkage void __do_softirq(void) __local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET); in_hardirq = lockdep_softirq_start(); - cpu = smp_processor_id(); restart: /* Reset the pending bitmask before enabling irqs */ set_softirq_pending(0); @@ -276,11 +274,11 @@ restart: prev_count, preempt_count()); preempt_count_set(prev_count); } - rcu_bh_qs(cpu); h++; pending >>= softirq_bit; } + rcu_bh_qs(smp_processor_id()); local_irq_disable(); pending = local_softirq_pending();