On 7/3/24 06:49, Xavier wrote:
Hi Michal and Longman,
Please confirm my explanation about cgroup v2 below.
At 2024-07-03 17:40:49, "Michal Koutný" <mkoutny@xxxxxxxx> wrote:
On Wed, Jul 03, 2024 at 02:37:27PM GMT, Xavier <xavier_qy@xxxxxxx> wrote:
@@ -1102,31 +1101,25 @@ static int generate_sched_domains(cpumask_var_t **domains,
if (root_load_balance && (csn == 1))
goto single_root_domain;
- for (i = 0; i < csn; i++)
- csa[i]->pn = i;
- ndoms = csn;
-
-restart:
- /* Find the best partition (set of sched domains) */
- for (i = 0; i < csn; i++) {
- struct cpuset *a = csa[i];
- int apn = a->pn;
-
- for (j = 0; j < csn; j++) {
- struct cpuset *b = csa[j];
- int bpn = b->pn;
-
- if (apn != bpn && cpusets_overlap(a, b)) {
- for (k = 0; k < csn; k++) {
- struct cpuset *c = csa[k];
+ if (!cgrpv2) {
I'm surprised that original code wasn't branched on this on you add it
here. Why is UF used only for v1 code?
In the Patch v6, I explained to Longman that based on his new patch, the overlapping check and
merge operations for cpusets are skipped in the case of cgroup v2. Because for cgroup v2,
doms[i] is merely copied from csa[i] rather than merged.
This needs further confirmation from Longman.
Actually, I would like to keep the cpuset merging part for both cgroup
v1 and v2. I did notice that the hotplug code path can sometimes cause
overlapping partition roots in some intermediate states. I will try to
get it of that and use the merging part to verify that all partition
roots are mutually exclusive.
Cheers,
Longman
