Commit-ID: 07f06cb3b5f6bd21374a48dbefdb431d71d53974 Gitweb: http://git.kernel.org/tip/07f06cb3b5f6bd21374a48dbefdb431d71d53974 Author: Peter Zijlstra <pet...@infradead.org> AuthorDate: Fri, 9 Oct 2015 18:00:54 +0200 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Tue, 20 Oct 2015 10:25:55 +0200
sched: Start stopper early Ensure the stopper thread is active 'early', because the load balancer pretty much assumes that its available. And when 'online && active' the load-balancer is fully available. Not only the numa balancing stop_two_cpus() caller relies on it, but also the self migration stuff does, and at CPU_ONLINE time the cpu really is 'free' to run anything. Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Signed-off-by: Oleg Nesterov <o...@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Andrew Morton <a...@linux-foundation.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Mike Galbraith <efa...@gmx.de> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Rik van Riel <r...@redhat.com> Cc: Tejun Heo <t...@kernel.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: heiko.carst...@de.ibm.com Link: http://lkml.kernel.org/r/20151009160054.ga10...@redhat.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/cpu.c | 1 - kernel/sched/core.c | 12 +++++++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/cpu.c b/kernel/cpu.c index 6467521..c85df27 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -475,7 +475,6 @@ static int smpboot_thread_call(struct notifier_block *nfb, case CPU_DOWN_FAILED: case CPU_ONLINE: - stop_machine_unpark(cpu); smpboot_unpark_threads(cpu); break; diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f45a7c7..7ee8cae 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5545,21 +5545,27 @@ static void set_cpu_rq_start_time(void) static int sched_cpu_active(struct notifier_block *nfb, unsigned long action, void *hcpu) { + int cpu = (long)hcpu; + switch (action & ~CPU_TASKS_FROZEN) { case CPU_STARTING: set_cpu_rq_start_time(); return NOTIFY_OK; + case CPU_ONLINE: /* * At this point a starting CPU has marked itself as online via * set_cpu_online(). But it might not yet have marked itself * as active, which is essential from here on. - * - * Thus, fall-through and help the starting CPU along. */ + set_cpu_active(cpu, true); + stop_machine_unpark(cpu); + return NOTIFY_OK; + case CPU_DOWN_FAILED: - set_cpu_active((long)hcpu, true); + set_cpu_active(cpu, true); return NOTIFY_OK; + default: return NOTIFY_DONE; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
