Messages in this thread Patch in this message | | | From | Lai Jiangshan <> | Subject | [PATCH 2/6] Don't touch the snap in srcu_readers_active() | Date | Tue, 6 Mar 2012 17:57:34 +0800 |
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srcu_readers_active() is called without the mutex, but it touch the snap. also achieve better cache locality a little
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> --- kernel/srcu.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/kernel/srcu.c b/kernel/srcu.c index b6b9ea2..fbe2d5f 100644 --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -181,7 +181,14 @@ static bool srcu_readers_active_idx_check(struct srcu_struct *sp, int idx) */ static int srcu_readers_active(struct srcu_struct *sp) { - return srcu_readers_active_idx(sp, 0) + srcu_readers_active_idx(sp, 1); + int cpu; + unsigned long sum = 0; + + for_each_possible_cpu(cpu) { + sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[0]); + sum += ACCESS_ONCE(per_cpu_ptr(sp->per_cpu_ref, cpu)->c[1]); + } + return sum & SRCU_REF_MASK; } /** -- 1.7.4.4
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