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| author | Eric Dumazet <edumazet@google.com> | 2014-04-16 09:06:24 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-04-29 08:45:40 -0700 |
| commit | a5d6d3a1b00a0ad88f07c3a727c79b27915278e3 (patch) | |
| tree | 0be0f5f7f7d538fcd6ec500b6a2f9380160da3e5 | |
| parent | fa07a58f71ee23a82597ce337126982d0cc60b72 (diff) | |
| download | op-kernel-dev-a5d6d3a1b00a0ad88f07c3a727c79b27915278e3.zip op-kernel-dev-a5d6d3a1b00a0ad88f07c3a727c79b27915278e3.tar.gz | |
softirq: A single rcu_bh_qs() call per softirq set is enough
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>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
| -rw-r--r-- | kernel/softirq.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c index b50990a..b9b2d49 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(); |
