On Sat, May 25, 2024 at 09:46:48AM +0000, Xiu Jianfeng wrote: > In the cpuset_css_online(), clearing the CS_SCHED_LOAD_BALANCE bit > of cs->flags is guarded by callback_lock and cpuset_mutex. There is > no problem with itself, because it is consistent with the description > of there two global lock at the beginning of this file. However, since > the operation of checking, setting and clearing the flag bit is atomic, > protection of callback_lock is unnecessary here, see CS_SPREAD_*. so > to make it more consistent with the other code, move the operation > outside the critical section of callback_lock. > > No functional changes intended. > > Signed-off-by: Xiu Jianfeng <xiujianfeng@xxxxxxxxxx> > --- > kernel/cgroup/cpuset.c | 14 ++++++-------- > 1 file changed, 6 insertions(+), 8 deletions(-) > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index f9d2a3487645..315f8cbd6d35 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -4038,6 +4038,12 @@ static int cpuset_css_online(struct cgroup_subsys_state *css) > set_bit(CS_SPREAD_PAGE, &cs->flags); > if (is_spread_slab(parent)) > set_bit(CS_SPREAD_SLAB, &cs->flags); > + /* > + * For v2, clear CS_SCHED_LOAD_BALANCE if parent is isolated > + */ > + if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) && > + !is_sched_load_balance(parent)) > + clear_bit(CS_SCHED_LOAD_BALANCE, &cs->flags); The code looks weird to me. It's doing the same thing under the is_in_v2_mode() block and the cgroup_subsys_on_dfl() block and the former is also run when the latter condition is true. Looks like we can get rid of the latter block? Waiman? Thanks. -- tejun
