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authorGregory Haskins <ghaskins@novell.com>2008-01-25 21:08:18 +0100
committerIngo Molnar <mingo@elte.hu>2008-01-25 21:08:18 +0100
commit637f50851b57a32f7ec67c50fc16f1601ab1a87a (patch)
treeee8a4bc19fda1783bff8aa44abdcb6d8596aa7f1 /kernel/sched.c
parent57d885fea0da0e9541d7730a9e1dcf734981a173 (diff)
downloadop-kernel-dev-637f50851b57a32f7ec67c50fc16f1601ab1a87a.zip
op-kernel-dev-637f50851b57a32f7ec67c50fc16f1601ab1a87a.tar.gz
sched: only balance our RT tasks within our domain
We move the rt-overload data as the first global to per-domain reclassification. This limits the scope of overload related cache-line bouncing to stay with a specified partition instead of affecting all cpus in the system. Finally, we limit the scope of find_lowest_cpu searches to the domain instead of the entire system. Note that we would always respect domain boundaries even without this patch, but we first would scan potentially all cpus before whittling the list down. Now we can avoid looking at RQs that are out of scope, again reducing cache-line hits. Note: In some cases, task->cpus_allowed will effectively reduce our search to within our domain. However, I believe there are cases where the cpus_allowed mask may be all ones and therefore we err on the side of caution. If it can be optimized later, so be it. Signed-off-by: Gregory Haskins <ghaskins@novell.com> CC: Christoph Lameter <clameter@sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 34b7d72..35ef06c 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -365,6 +365,13 @@ struct root_domain {
atomic_t refcount;
cpumask_t span;
cpumask_t online;
+
+ /*
+ * The "RT overload" flag: it gets set if a CPU has more than
+ * one runnable RT task.
+ */
+ cpumask_t rto_mask;
+ atomic_t rto_count;
};
static struct root_domain def_root_domain;
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