From: Sasha Levin Date: Mon, 21 Jun 2021 02:03:39 +0000 (-0400) Subject: Fixes for 5.4 X-Git-Tag: v5.4.128~40 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e2c3bd218e565524e835e790022e767c9b476d49;p=thirdparty%2Fkernel%2Fstable-queue.git Fixes for 5.4 Signed-off-by: Sasha Levin --- diff --git a/queue-5.4/sched-fair-correctly-insert-cfs_rq-s-to-list-on-unth.patch b/queue-5.4/sched-fair-correctly-insert-cfs_rq-s-to-list-on-unth.patch new file mode 100644 index 00000000000..959e8f08de9 --- /dev/null +++ b/queue-5.4/sched-fair-correctly-insert-cfs_rq-s-to-list-on-unth.patch @@ -0,0 +1,120 @@ +From 2ce8185d181f56f500e24da1d506d97c762927b6 Mon Sep 17 00:00:00 2001 +From: Sasha Levin +Date: Sat, 12 Jun 2021 13:28:15 +0200 +Subject: sched/fair: Correctly insert cfs_rq's to list on unthrottle + +From: Odin Ugedal + +[ Upstream commit a7b359fc6a37faaf472125867c8dc5a068c90982 ] + +Fix an issue where fairness is decreased since cfs_rq's can end up not +being decayed properly. For two sibling control groups with the same +priority, this can often lead to a load ratio of 99/1 (!!). + +This happens because when a cfs_rq is throttled, all the descendant +cfs_rq's will be removed from the leaf list. When they initial cfs_rq +is unthrottled, it will currently only re add descendant cfs_rq's if +they have one or more entities enqueued. This is not a perfect +heuristic. + +Instead, we insert all cfs_rq's that contain one or more enqueued +entities, or it its load is not completely decayed. + +Can often lead to situations like this for equally weighted control +groups: + + $ ps u -C stress + USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND + root 10009 88.8 0.0 3676 100 pts/1 R+ 11:04 0:13 stress --cpu 1 + root 10023 3.0 0.0 3676 104 pts/1 R+ 11:04 0:00 stress --cpu 1 + +Fixes: 31bc6aeaab1d ("sched/fair: Optimize update_blocked_averages()") +[vingo: !SMP build fix] +Signed-off-by: Odin Ugedal +Signed-off-by: Peter Zijlstra (Intel) +Reviewed-by: Vincent Guittot +Link: https://lore.kernel.org/r/20210612112815.61678-1-odin@uged.al +Signed-off-by: Sasha Levin +--- + kernel/sched/fair.c | 44 +++++++++++++++++++++++++------------------- + 1 file changed, 25 insertions(+), 19 deletions(-) + +diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c +index d3f4113e87de..877672df822f 100644 +--- a/kernel/sched/fair.c ++++ b/kernel/sched/fair.c +@@ -3131,6 +3131,24 @@ static inline void cfs_rq_util_change(struct cfs_rq *cfs_rq, int flags) + + #ifdef CONFIG_SMP + #ifdef CONFIG_FAIR_GROUP_SCHED ++ ++static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) ++{ ++ if (cfs_rq->load.weight) ++ return false; ++ ++ if (cfs_rq->avg.load_sum) ++ return false; ++ ++ if (cfs_rq->avg.util_sum) ++ return false; ++ ++ if (cfs_rq->avg.runnable_load_sum) ++ return false; ++ ++ return true; ++} ++ + /** + * update_tg_load_avg - update the tg's load avg + * @cfs_rq: the cfs_rq whose avg changed +@@ -3833,6 +3851,11 @@ static inline void update_misfit_status(struct task_struct *p, struct rq *rq) + + #else /* CONFIG_SMP */ + ++static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) ++{ ++ return true; ++} ++ + #define UPDATE_TG 0x0 + #define SKIP_AGE_LOAD 0x0 + #define DO_ATTACH 0x0 +@@ -4488,8 +4511,8 @@ static int tg_unthrottle_up(struct task_group *tg, void *data) + cfs_rq->throttled_clock_task_time += rq_clock_task(rq) - + cfs_rq->throttled_clock_task; + +- /* Add cfs_rq with already running entity in the list */ +- if (cfs_rq->nr_running >= 1) ++ /* Add cfs_rq with load or one or more already running entities to the list */ ++ if (!cfs_rq_is_decayed(cfs_rq) || cfs_rq->nr_running) + list_add_leaf_cfs_rq(cfs_rq); + } + +@@ -7620,23 +7643,6 @@ static bool __update_blocked_others(struct rq *rq, bool *done) + + #ifdef CONFIG_FAIR_GROUP_SCHED + +-static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq) +-{ +- if (cfs_rq->load.weight) +- return false; +- +- if (cfs_rq->avg.load_sum) +- return false; +- +- if (cfs_rq->avg.util_sum) +- return false; +- +- if (cfs_rq->avg.runnable_load_sum) +- return false; +- +- return true; +-} +- + static bool __update_blocked_fair(struct rq *rq, bool *done) + { + struct cfs_rq *cfs_rq, *pos; +-- +2.30.2 + diff --git a/queue-5.4/series b/queue-5.4/series index 4eb724de23b..3b2cd0f6b44 100644 --- a/queue-5.4/series +++ b/queue-5.4/series @@ -46,3 +46,4 @@ spi-stm32-qspi-always-wait-busy-bit-to-be-cleared-in.patch pinctrl-ralink-rt2880-avoid-to-error-in-calls-is-pin.patch radeon-use-memcpy_to-fromio-for-uvd-fw-upload.patch hwmon-scpi-hwmon-shows-the-negative-temperature-prop.patch +sched-fair-correctly-insert-cfs_rq-s-to-list-on-unth.patch