From: Eric Dumazet Date: Mon, 17 Oct 2005 18:01:21 +0000 (+0200) Subject: [PATCH] rcu: keep rcu callback event counter X-Git-Tag: v2.6.14-rc5~27 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5ee832dbc6770135ec8d63296af0a4374557bb79;p=linux-2.6 [PATCH] rcu: keep rcu callback event counter This makes call_rcu() keep track of how many events there are on the RCU list, and cause a reschedule event when the list gets too long. This helps keep RCU event lists down. Signed-off-by: Linus Torvalds --- diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 4e65eb44ad..70191a5a14 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -94,6 +94,7 @@ struct rcu_data { long batch; /* Batch # for current RCU batch */ struct rcu_head *nxtlist; struct rcu_head **nxttail; + long count; /* # of queued items */ struct rcu_head *curlist; struct rcu_head **curtail; struct rcu_head *donelist; diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c index dd99415b15..2559d4b8f2 100644 --- a/kernel/rcupdate.c +++ b/kernel/rcupdate.c @@ -109,6 +109,10 @@ void fastcall call_rcu(struct rcu_head *head, rdp = &__get_cpu_var(rcu_data); *rdp->nxttail = head; rdp->nxttail = &head->next; + + if (unlikely(++rdp->count > 10000)) + set_need_resched(); + local_irq_restore(flags); } @@ -140,6 +144,12 @@ void fastcall call_rcu_bh(struct rcu_head *head, rdp = &__get_cpu_var(rcu_bh_data); *rdp->nxttail = head; rdp->nxttail = &head->next; + rdp->count++; +/* + * Should we directly call rcu_do_batch() here ? + * if (unlikely(rdp->count > 10000)) + * rcu_do_batch(rdp); + */ local_irq_restore(flags); } @@ -157,6 +167,7 @@ static void rcu_do_batch(struct rcu_data *rdp) next = rdp->donelist = list->next; list->func(list); list = next; + rdp->count--; if (++count >= maxbatch) break; }