On Fri, Sep 04, 2026 at 02:20:11PM +0800, Zhe Liu <[email protected]> wrote: > Keep the configured burst independent of the current quota and cap it > when CFS refills runtime. This allows quota and burst updates in either > order. > > Fixes: f4183717b370 ("sched/fair: Introduce the burstable CFS controller") > > Cc: [email protected]
The change makes sense to me and it should've been like that from the beginning. OTOH, it may break someone's setup, so I'd take it but revert it should regressions be reported. Hence, I wouldn't mark it for stable. > Signed-off-by: Zhe Liu <[email protected]> > --- > kernel/sched/core.c | 3 +-- > kernel/sched/fair.c | 3 ++- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index f78275192036..5269b8cfcf7f 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -10159,8 +10159,7 @@ static int tg_set_bandwidth(struct task_group *tg, > if (quota_us != RUNTIME_INF && quota_us > max_bw_runtime_us) > return -EINVAL; > > - if (quota_us != RUNTIME_INF && (burst_us > quota_us || > - burst_us + quota_us > > max_bw_runtime_us)) > + if (burst_us > max_bw_runtime_us) > return -EINVAL; I notice this'd be relaxed rather like: if (burst_us > max_bw_runtime_us / 2) return -EINVAL; I don't see in the current code that these BW_SHIFT'd calculations were relevant for burst. (Sashiko mentions overflows of the addition but I think it's confused MAX_BW and UULONG_MAX or more precisely (UULONG_MAX / NSEC_PER_USEC),) so even your version should still be safe. (Without that stable annotation above.) Reviewed-by: Michal Koutný <[email protected]>
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