From 6a5ebbb1fcfa25a4f0aa4c16b4abd63c1e7718bf Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Thu, 9 Apr 2020 09:10:55 +0200 Subject: [PATCH] sched: fix onlining cpu with core scheduling active When onlining a cpu cpupool_cpu_add() checks whether all siblings of the new cpu are free in order to decide whether to add it to cpupool0. In case the added cpu is not the last sibling to be onlined this test is wrong as it only checks for all online siblings to be free. The test should include the check for the number of siblings having reached the scheduling granularity of cpupool0, too. Signed-off-by: Juergen Gross Reviewed-by: Dario Faggioli master commit: 4c7d340f75abc64f131b0f9bffd6d66d72e43528 master date: 2020-03-24 17:36:44 +0100 --- xen/common/cpupool.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/xen/common/cpupool.c b/xen/common/cpupool.c index 5a90bdc9ff..b90bf42703 100644 --- a/xen/common/cpupool.c +++ b/xen/common/cpupool.c @@ -615,7 +615,8 @@ static int cpupool_cpu_add(unsigned int cpu) get_sched_res(cpu)->cpupool = NULL; cpus = sched_get_opt_cpumask(cpupool0->gran, cpu); - if ( cpumask_subset(cpus, &cpupool_free_cpus) ) + if ( cpumask_subset(cpus, &cpupool_free_cpus) && + cpumask_weight(cpus) == cpupool_get_granularity(cpupool0) ) ret = cpupool_assign_cpu_locked(cpupool0, cpu); rcu_read_unlock(&sched_res_rculock);