diff options
| author | Zhan Xusheng <zhanxusheng1024@gmail.com> | 2026-01-14 17:00:35 +0800 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2026-01-15 22:41:26 +0100 |
| commit | 553255cc857c08d72658b57d01c04f76cde9a83a (patch) | |
| tree | 83dac19b1ffe61a7327ccc87339d69ae254706f1 /kernel | |
| parent | 8d737320166bd145af70a3133a9964b00ca81cba (diff) | |
| download | lwn-553255cc857c08d72658b57d01c04f76cde9a83a.tar.gz lwn-553255cc857c08d72658b57d01c04f76cde9a83a.zip | |
sched/fair: Fix math notation errors in avg_vruntime comment
The avg_vruntime comment contains a couple of mathematical notation
issues:
- The summation over w_i * (V - v_i) is written in an ambiguous form
- The delta term refers to v instead of v0, which is inconsistent
with the code and preceding explanation
Fix these to make the comment mathematically correct and consistent
with the implementation.
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260114090035.19033-1-zhanxusheng@xiaomi.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ebee20f75fa0..af120e88720f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -613,7 +613,7 @@ static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) * * \Sum lag_i = 0 * \Sum w_i * (V - v_i) = 0 - * \Sum w_i * V - w_i * v_i = 0 + * \Sum (w_i * V - w_i * v_i) = 0 * * From which we can solve an expression for V in v_i (which we have in * se->vruntime): @@ -648,7 +648,7 @@ static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se) * \Sum w_i := cfs_rq->sum_weight * * Since zero_vruntime closely tracks the per-task service, these - * deltas: (v_i - v), will be in the order of the maximal (virtual) lag + * deltas: (v_i - v0), will be in the order of the maximal (virtual) lag * induced in the system due to quantisation. * * Also, we use scale_load_down() to reduce the size. |