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authorChristoph Lameter <clameter@sgi.com>2006-12-10 05:20:29 -0500
committerLinus Torvalds <torvalds@woody.osdl.org>2006-12-10 12:55:43 -0500
commit08c183f31bdbb709f177f6d3110d5f288ea33933 (patch)
treebe7b84c07f3b0bf29473bad2b7b788fa189f948e /kernel
parent1bd77f2da58e9cdd1f159217887343dadd9af417 (diff)
[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 <clameter@sgi.com> Cc: Peter Williams <pwil3058@bigpond.net.au> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <clameter@sgi.com> Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com> Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 0a4a26b21f69..2b2b780939c9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2880,6 +2880,7 @@ static void update_load(struct rq *this_rq)
2880 * 2880 *
2881 * Balancing parameters are set up in arch_init_sched_domains. 2881 * Balancing parameters are set up in arch_init_sched_domains.
2882 */ 2882 */
2883static DEFINE_SPINLOCK(balancing);
2883 2884
2884static void run_rebalance_domains(struct softirq_action *h) 2885static void run_rebalance_domains(struct softirq_action *h)
2885{ 2886{
@@ -2909,6 +2910,11 @@ static void run_rebalance_domains(struct softirq_action *h)
2909 if (unlikely(!interval)) 2910 if (unlikely(!interval))
2910 interval = 1; 2911 interval = 1;
2911 2912
2913 if (sd->flags & SD_SERIALIZE) {
2914 if (!spin_trylock(&balancing))
2915 goto out;
2916 }
2917
2912 if (time_after_eq(jiffies, sd->last_balance + interval)) { 2918 if (time_after_eq(jiffies, sd->last_balance + interval)) {
2913 if (load_balance(this_cpu, this_rq, sd, idle)) { 2919 if (load_balance(this_cpu, this_rq, sd, idle)) {
2914 /* 2920 /*
@@ -2920,6 +2926,9 @@ static void run_rebalance_domains(struct softirq_action *h)
2920 } 2926 }
2921 sd->last_balance = jiffies; 2927 sd->last_balance = jiffies;
2922 } 2928 }
2929 if (sd->flags & SD_SERIALIZE)
2930 spin_unlock(&balancing);
2931out:
2923 if (time_after(next_balance, sd->last_balance + interval)) 2932 if (time_after(next_balance, sd->last_balance + interval))
2924 next_balance = sd->last_balance + interval; 2933 next_balance = sd->last_balance + interval;
2925 } 2934 }