| Message ID | 20200310090642.8476-1-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] xen/sched: fix onlining cpu with core scheduling active | expand |
Ping? On 10.03.20 10:06, Juergen Gross wrote: > 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 <jgross@suse.com> > --- > V2: > - modify condition form >= to == (Jan Beulich) > --- > xen/common/sched/cpupool.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c > index 9f70c7ec17..d40345b585 100644 > --- a/xen/common/sched/cpupool.c > +++ b/xen/common/sched/cpupool.c > @@ -616,7 +616,8 @@ 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); >
On Tue, 2020-03-10 at 10:06 +0100, Juergen Gross wrote: > 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 <jgross@suse.com> > Reviewed-by: Dario Faggioli <dfaggioli@suse.com> Regards
diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c index 9f70c7ec17..d40345b585 100644 --- a/xen/common/sched/cpupool.c +++ b/xen/common/sched/cpupool.c @@ -616,7 +616,8 @@ 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);
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 <jgross@suse.com> --- V2: - modify condition form >= to == (Jan Beulich) --- xen/common/sched/cpupool.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)