This patch reduce scans of srcu_data in case of a srcu_struct tree have more than one levels
Signed-off-by: Ildar Ismagilov <[email protected]> --- kernel/rcu/srcutree.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index c54617280245..2268381706d2 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -500,6 +500,7 @@ static void srcu_gp_end(struct srcu_struct *sp) { unsigned long cbdelay; bool cbs; + bool last_lvl; int cpu; unsigned long flags; unsigned long gpseq; @@ -532,7 +533,8 @@ static void srcu_gp_end(struct srcu_struct *sp) rcu_for_each_node_breadth_first(sp, snp) { raw_spin_lock_irq_rcu_node(snp); cbs = false; - if (snp >= sp->level[rcu_num_lvls - 1]) + last_lvl = snp >= sp->level[rcu_num_lvls - 1]; + if (last_lvl) cbs = snp->srcu_have_cbs[idx] == gpseq; snp->srcu_have_cbs[idx] = gpseq; rcu_seq_set_state(&snp->srcu_have_cbs[idx], 1); @@ -545,7 +547,7 @@ static void srcu_gp_end(struct srcu_struct *sp) srcu_schedule_cbs_snp(sp, snp, mask, cbdelay); /* Occasionally prevent srcu_data counter wrap. */ - if (!(gpseq & counter_wrap_check)) + if (!(gpseq & counter_wrap_check) && last_lvl) for (cpu = snp->grplo; cpu <= snp->grphi; cpu++) { sdp = per_cpu_ptr(sp->sda, cpu); raw_spin_lock_irqsave_rcu_node(sdp, flags); -- 2.11.0
