From 08c183f31bdbb709f177f6d3110d5f288ea33933 Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Sun, 10 Dec 2006 02:20:29 -0800 Subject: [PATCH] sched: add option to serialize load balancing Large sched domains can be very expensive to scan. Add an option SD_SERIALIZE to the sched domain flags. If that flag is set then we make sure that no other such domain is being balanced. [akpm@osdl.org: build fix] Signed-off-by: Christoph Lameter Cc: Peter Williams Cc: Nick Piggin Cc: Christoph Lameter Cc: "Siddha, Suresh B" Cc: "Chen, Kenneth W" Acked-by: Ingo Molnar Cc: KAMEZAWA Hiroyuki Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sched.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'kernel') diff --git a/kernel/sched.c b/kernel/sched.c index 0a4a26b21f6..2b2b780939c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2880,6 +2880,7 @@ static void update_load(struct rq *this_rq) * * Balancing parameters are set up in arch_init_sched_domains. */ +static DEFINE_SPINLOCK(balancing); static void run_rebalance_domains(struct softirq_action *h) { @@ -2909,6 +2910,11 @@ static void run_rebalance_domains(struct softirq_action *h) if (unlikely(!interval)) interval = 1; + if (sd->flags & SD_SERIALIZE) { + if (!spin_trylock(&balancing)) + goto out; + } + if (time_after_eq(jiffies, sd->last_balance + interval)) { if (load_balance(this_cpu, this_rq, sd, idle)) { /* @@ -2920,6 +2926,9 @@ static void run_rebalance_domains(struct softirq_action *h) } sd->last_balance = jiffies; } + if (sd->flags & SD_SERIALIZE) + spin_unlock(&balancing); +out: if (time_after(next_balance, sd->last_balance + interval)) next_balance = sd->last_balance + interval; } -- cgit v1.2.3