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authorPeter Zijlstra <peterz@infradead.org>2017-08-08 13:16:24 +0300
committerIngo Molnar <mingo@kernel.org>2017-08-25 12:12:20 +0300
commit09e0dd8e0f2e197690d34fed8cb4737114d3dd5f (patch)
tree5f44fac23c7fc9f088a99d47d78e98cb0f53b1c3 /kernel
parent77d1dfda0e79b41894880418f04794e92e4350e2 (diff)
downloadlinux-09e0dd8e0f2e197690d34fed8cb4737114d3dd5f.tar.xz
sched/topology: Avoid pointless rebuild
Fix partition_sched_domains() to try and preserve the existing machine wide domain instead of unconditionally destroying it. We do this by attempting to allocate the new single domain, only when that fails to we reuse the fallback_doms. When using fallback_doms we need to first destroy and then recreate because both the old and new could be backed by it. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ofer Levi(SW) <oferle@mellanox.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vineet.Gupta1@synopsys.com <Vineet.Gupta1@synopsys.com> Cc: rusty@rustcorp.com.au <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/topology.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 179b90b60ec6..727daa2a0abe 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1851,7 +1851,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
/* Let the architecture update CPU core mappings: */
new_topology = arch_update_cpu_topology();
- n = doms_new ? ndoms_new : 0;
+ if (!doms_new) {
+ WARN_ON_ONCE(dattr_new);
+ n = 0;
+ doms_new = alloc_sched_domains(1);
+ if (doms_new) {
+ n = 1;
+ cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
+ }
+ } else {
+ n = ndoms_new;
+ }
/* Destroy deleted domains: */
for (i = 0; i < ndoms_cur; i++) {
@@ -1867,11 +1877,10 @@ match1:
}
n = ndoms_cur;
- if (doms_new == NULL) {
+ if (!doms_new) {
n = 0;
doms_new = &fallback_doms;
cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
- WARN_ON_ONCE(dattr_new);
}
/* Build new domains: */