Zhe Liu <[email protected]> writes: > Burst validation currently depends on the active quota, so the same quota > and burst values may be accepted or rejected depending on the order in > which userspace updates them. > > Make burst validation independent of the current quota while preserving, > for finite quotas, the previous maximum configurable burst at > max_bw_runtime_us / 2. Keep the configured burst across quota updates and > cap the effective burst to min(burst, quota) when CFS runtime is refilled. > > Fixes: f4183717b370 ("sched/fair: Introduce the burstable CFS controller") > Signed-off-by: Zhe Liu <[email protected]> > Tested-by: Tao Cui <[email protected]> > Reviewed-by: Michal Koutný <[email protected]>
Yeah, all the state validation that winds up requiring doing edits in a particular order is annoying and imo not particularly valuable. Reviewed-by: Ben Segall <[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 b998ef6b87af..c399f0a59c25 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -10181,8 +10181,7 @@ 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 / 2) > return -EINVAL; > > #ifdef CONFIG_CFS_BANDWIDTH > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index ade1eceb39b8..e6f9d9296fd2 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -6627,7 +6627,8 @@ void __refill_cfs_bandwidth_runtime(struct > cfs_bandwidth *cfs_b) > cfs_b->nr_burst++; > } > > - cfs_b->runtime = min(cfs_b->runtime, cfs_b->quota + cfs_b->burst); > + cfs_b->runtime = min(cfs_b->runtime, > + cfs_b->quota + min(cfs_b->burst, cfs_b->quota)); > cfs_b->runtime_snap = cfs_b->runtime; > }
