* [PATCH v2 0/2] Avoid obvious double update_rq_clock warning
@ 2022-04-22 9:09 Hao Jia
2022-04-22 9:09 ` [PATCH v2 1/2] sched/core: " Hao Jia
2022-04-22 9:09 ` [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task Hao Jia
0 siblings, 2 replies; 7+ messages in thread
From: Hao Jia @ 2022-04-22 9:09 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, bristot
Cc: linux-kernel, Hao Jia
These two patches are about the kernel scheduler:
patch 1: fixed the issue that kernel may trigger WARN_DOUBLE_CLOCK warning.
patch 2: removed some no longer needed comments in the deadline scheduler
and cleaned up the code.
v2:
- Added double_rq_clock_clear_update inline helper to clear RQCF_UPDATED
of rq->clock_update_flags.
- split into two separate patches.
[1] https://lore.kernel.org/lkml/20220418090929.54005-1-jiahao.os@bytedance.com/
Hao Jia (2):
sched/core: Avoid obvious double update_rq_clock warning
sched/dl: Remove some comments and adjust code in push_dl_task
kernel/sched/core.c | 6 +++---
kernel/sched/deadline.c | 8 +-------
kernel/sched/rt.c | 5 +++--
kernel/sched/sched.h | 31 +++++++++++++++++++++++++++----
4 files changed, 34 insertions(+), 16 deletions(-)
--
2.32.0
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH v2 1/2] sched/core: Avoid obvious double update_rq_clock warning 2022-04-22 9:09 [PATCH v2 0/2] Avoid obvious double update_rq_clock warning Hao Jia @ 2022-04-22 9:09 ` Hao Jia 2022-04-25 15:37 ` Dietmar Eggemann 2022-04-22 9:09 ` [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task Hao Jia 1 sibling, 1 reply; 7+ messages in thread From: Hao Jia @ 2022-04-22 9:09 UTC (permalink / raw) To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, bristot Cc: linux-kernel, Hao Jia When we use raw_spin_rq_lock to acquire the rq lock and have to update the rq clock while holding the lock, the kernel may issue a WARN_DOUBLE_CLOCK warning. Since we directly use raw_spin_rq_lock to acquire rq lock instead of rq_lock, there is no corresponding change to rq->clock_update_flags. In particular, we have obtained the rq lock of other cores, the core rq->clock_update_flags may be RQCF_UPDATED at this time, and then calling update_rq_clock will trigger the WARN_DOUBLE_CLOCK warning. So we need to clear RQCF_UPDATED of rq->clock_update_flags synchronously to avoid the WARN_DOUBLE_CLOCK warning. Some call trace reports: Call Trace 1: <IRQ> sched_rt_period_timer+0x10f/0x3a0 ? enqueue_top_rt_rq+0x110/0x110 __hrtimer_run_queues+0x1a9/0x490 hrtimer_interrupt+0x10b/0x240 __sysvec_apic_timer_interrupt+0x8a/0x250 sysvec_apic_timer_interrupt+0x9a/0xd0 </IRQ> <TASK> asm_sysvec_apic_timer_interrupt+0x12/0x20 Call Trace 2: <TASK> activate_task+0x8b/0x110 push_rt_task.part.108+0x241/0x2c0 push_rt_tasks+0x15/0x30 finish_task_switch+0xaa/0x2e0 ? __switch_to+0x134/0x420 __schedule+0x343/0x8e0 ? hrtimer_start_range_ns+0x101/0x340 schedule+0x4e/0xb0 do_nanosleep+0x8e/0x160 hrtimer_nanosleep+0x89/0x120 ? hrtimer_init_sleeper+0x90/0x90 __x64_sys_nanosleep+0x96/0xd0 do_syscall_64+0x34/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Call Trace 3: <TASK> deactivate_task+0x93/0xe0 pull_rt_task+0x33e/0x400 balance_rt+0x7e/0x90 __schedule+0x62f/0x8e0 do_task_dead+0x3f/0x50 do_exit+0x7b8/0xbb0 do_group_exit+0x2d/0x90 get_signal+0x9df/0x9e0 ? preempt_count_add+0x56/0xa0 ? __remove_hrtimer+0x35/0x70 arch_do_signal_or_restart+0x36/0x720 ? nanosleep_copyout+0x39/0x50 ? do_nanosleep+0x131/0x160 ? audit_filter_inodes+0xf5/0x120 exit_to_user_mode_prepare+0x10f/0x1e0 syscall_exit_to_user_mode+0x17/0x30 do_syscall_64+0x40/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Steps to reproduce: 1. Enable CONFIG_SCHED_DEBUG when compiling the kernel 2. echo 1 > /sys/kernel/debug/clear_warn_once echo "WARN_DOUBLE_CLOCK" > /sys/kernel/debug/sched_features echo "NO_RT_PUSH_IPI" > /sys/kernel/debug/sched_features 3. Run some rt tasks that periodically change the priority and sleep Signed-off-by: Hao Jia <jiahao.os@bytedance.com> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> --- kernel/sched/core.c | 6 +++--- kernel/sched/rt.c | 5 +++-- kernel/sched/sched.h | 31 +++++++++++++++++++++++++++---- 3 files changed, 33 insertions(+), 9 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 51efaabac3e4..84538271b4eb 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -610,10 +610,10 @@ void double_rq_lock(struct rq *rq1, struct rq *rq2) swap(rq1, rq2); raw_spin_rq_lock(rq1); - if (__rq_lockp(rq1) == __rq_lockp(rq2)) - return; + if (__rq_lockp(rq1) != __rq_lockp(rq2)) + raw_spin_rq_lock_nested(rq2, SINGLE_DEPTH_NESTING); - raw_spin_rq_lock_nested(rq2, SINGLE_DEPTH_NESTING); + double_rq_clock_clear_update(rq1, rq2); } #endif diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index a32c46889af8..7891c0f0e1ff 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -871,6 +871,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) int enqueue = 0; struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i); struct rq *rq = rq_of_rt_rq(rt_rq); + struct rq_flags rf; int skip; /* @@ -885,7 +886,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (skip) continue; - raw_spin_rq_lock(rq); + rq_lock(rq, &rf); update_rq_clock(rq); if (rt_rq->rt_time) { @@ -923,7 +924,7 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (enqueue) sched_rt_rq_enqueue(rt_rq); - raw_spin_rq_unlock(rq); + rq_unlock(rq, &rf); } if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 8dccb34eb190..7f1a18b2aff2 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2478,6 +2478,27 @@ unsigned long arch_scale_freq_capacity(int cpu) } #endif +#ifdef CONFIG_SCHED_DEBUG +/* + * In double_lock_balance/double_rq_lock, we use raw_spin_rq_lock to acquire rq lock + * instead of rq_lock. So at the end of these two functions we need to call + * double_rq_clock_clear_update synchronously to clear RQCF_UPDATED of + * rq->clock_update_flags to avoid the WARN_DOUBLE_CLOCK warning. + */ +static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) +{ + rq1->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP); + /* + * If CONFIG_SMP is not defined, rq1 and rq2 are the same, + * so we just clear RQCF_UPDATED one of them. + */ +#ifdef CONFIG_SMP + rq2->clock_update_flags &= (RQCF_REQ_SKIP|RQCF_ACT_SKIP); +#endif +} +#else +static inline void double_rq_clock_clear_update(struct rq *rq1, struct rq *rq2) {} +#endif #ifdef CONFIG_SMP @@ -2543,14 +2564,15 @@ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest) __acquires(busiest->lock) __acquires(this_rq->lock) { - if (__rq_lockp(this_rq) == __rq_lockp(busiest)) - return 0; - - if (likely(raw_spin_rq_trylock(busiest))) + if (__rq_lockp(this_rq) == __rq_lockp(busiest) || + likely(raw_spin_rq_trylock(busiest))) { + double_rq_clock_clear_update(this_rq, busiest); return 0; + } if (rq_order_less(this_rq, busiest)) { raw_spin_rq_lock_nested(busiest, SINGLE_DEPTH_NESTING); + double_rq_clock_clear_update(this_rq, busiest); return 0; } @@ -2644,6 +2666,7 @@ static inline void double_rq_lock(struct rq *rq1, struct rq *rq2) BUG_ON(rq1 != rq2); raw_spin_rq_lock(rq1); __acquire(rq2->lock); /* Fake it out ;) */ + double_rq_clock_clear_update(rq1, rq2); } /* -- 2.32.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] sched/core: Avoid obvious double update_rq_clock warning 2022-04-22 9:09 ` [PATCH v2 1/2] sched/core: " Hao Jia @ 2022-04-25 15:37 ` Dietmar Eggemann 2022-04-26 7:57 ` [External] " Hao Jia 0 siblings, 1 reply; 7+ messages in thread From: Dietmar Eggemann @ 2022-04-25 15:37 UTC (permalink / raw) To: Hao Jia, mingo, peterz, juri.lelli, vincent.guittot, rostedt, bsegall, mgorman, bristot Cc: linux-kernel On 22/04/2022 11:09, Hao Jia wrote: > When we use raw_spin_rq_lock to acquire the rq lock and have to > update the rq clock while holding the lock, the kernel may issue > a WARN_DOUBLE_CLOCK warning. > > Since we directly use raw_spin_rq_lock to acquire rq lock instead of > rq_lock, there is no corresponding change to rq->clock_update_flags. > In particular, we have obtained the rq lock of other cores, > the core rq->clock_update_flags may be RQCF_UPDATED at this time, and > then calling update_rq_clock will trigger the WARN_DOUBLE_CLOCK warning. > > So we need to clear RQCF_UPDATED of rq->clock_update_flags synchronously > to avoid the WARN_DOUBLE_CLOCK warning. > > Some call trace reports: > Call Trace 1: > <IRQ> > sched_rt_period_timer+0x10f/0x3a0 > ? enqueue_top_rt_rq+0x110/0x110 > __hrtimer_run_queues+0x1a9/0x490 > hrtimer_interrupt+0x10b/0x240 [...] For the sched_rt_period_timer() case you simply replace raw_spin_rq_lock()/raw_spin_rq_unlock() with rq_lock()/rq_unlock(). I.e. you're not using the new double_rq_clock_clear_update() which is depicted in the text above. > Call Trace 2: > <TASK> > activate_task+0x8b/0x110 > push_rt_task.part.108+0x241/0x2c0 > push_rt_tasks+0x15/0x30 > finish_task_switch+0xaa/0x2e0 > ? __switch_to+0x134/0x420 > __schedule+0x343/0x8e0 [...] > Call Trace 3: > <TASK> > deactivate_task+0x93/0xe0 > pull_rt_task+0x33e/0x400 > balance_rt+0x7e/0x90 > __schedule+0x62f/0x8e0 > do_task_dead+0x3f/0x50 [...] > Steps to reproduce: > 1. Enable CONFIG_SCHED_DEBUG when compiling the kernel > 2. echo 1 > /sys/kernel/debug/clear_warn_once > echo "WARN_DOUBLE_CLOCK" > /sys/kernel/debug/sched_features s/sched_features/sched/features > echo "NO_RT_PUSH_IPI" > /sys/kernel/debug/sched_features s/sched_features/sched/features > 3. Run some rt tasks that periodically change the priority and sleep Not sure about the `change the priority` part? I'm using rt-app with 2*n rt or dl (90% running) tasks (on a system with n CPUs) and can trigger all of these cases. > Signed-off-by: Hao Jia <jiahao.os@bytedance.com> > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> You can remove this Signed-off-by. I can provide a Reviewed-By for the next version. [...] When running PREEMPT_RT kernel there is another similar case in DL. [ 215.158100] ------------[ cut here ]------------ [ 215.158105] rq->clock_update_flags & RQCF_UPDATED [ 215.158113] WARNING: CPU: 2 PID: 1942 at kernel/sched/core.c:690 update_rq_clock+0x128/0x1a0 ... [ 215.158245] update_rq_clock+0x128/0x1a0 [ 215.158253] migrate_task_rq_dl+0xec/0x310 <--- !!! [ 215.158259] set_task_cpu+0x84/0x1e4 [ 215.158264] try_to_wake_up+0x1d8/0x5c0 [ 215.158268] wake_up_process+0x1c/0x30 [ 215.158272] hrtimer_wakeup+0x24/0x3c [ 215.158279] __hrtimer_run_queues+0x114/0x270 [ 215.158285] hrtimer_interrupt+0xe8/0x244 [ 215.158291] arch_timer_handler_phys+0x30/0x50 [ 215.158301] handle_percpu_devid_irq+0x88/0x140 [ 215.158306] generic_handle_domain_irq+0x40/0x60 [ 215.158313] gic_handle_irq+0x48/0xe0 [ 215.158320] call_on_irq_stack+0x2c/0x60 [ 215.158327] do_interrupt_handler+0x80/0x84 For a non_contending task, this is the same issue as in sched_rt_period_timer(). -->8-- diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index cfe7b40bc4ff..668a9910cd6d 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -1804,6 +1804,7 @@ select_task_rq_dl(struct task_struct *p, int cpu, int flags) static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused) { + struct rq_flags rf; struct rq *rq; if (READ_ONCE(p->__state) != TASK_WAKING) @@ -1815,7 +1816,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused * from try_to_wake_up(). Hence, p->pi_lock is locked, but * rq->lock is not... So, lock it */ - raw_spin_rq_lock(rq); + rq_lock(rq, &rf); if (p->dl.dl_non_contending) { update_rq_clock(rq); sub_running_bw(&p->dl, &rq->dl); @@ -1831,7 +1832,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused put_task_struct(p); } sub_rq_bw(&p->dl, &rq->dl); - raw_spin_rq_unlock(rq); + rq_unlock(rq, &rf); } static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p) -- 2.25.1 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [External] Re: [PATCH v2 1/2] sched/core: Avoid obvious double update_rq_clock warning 2022-04-25 15:37 ` Dietmar Eggemann @ 2022-04-26 7:57 ` Hao Jia 0 siblings, 0 replies; 7+ messages in thread From: Hao Jia @ 2022-04-26 7:57 UTC (permalink / raw) To: Dietmar Eggemann, mingo, peterz, juri.lelli, vincent.guittot, rostedt, bsegall, mgorman, bristot Cc: linux-kernel On 2022/4/25 Dietmar Eggemann wrote: > On 22/04/2022 11:09, Hao Jia wrote: >> When we use raw_spin_rq_lock to acquire the rq lock and have to >> update the rq clock while holding the lock, the kernel may issue >> a WARN_DOUBLE_CLOCK warning. >> >> Since we directly use raw_spin_rq_lock to acquire rq lock instead of >> rq_lock, there is no corresponding change to rq->clock_update_flags. >> In particular, we have obtained the rq lock of other cores, >> the core rq->clock_update_flags may be RQCF_UPDATED at this time, and >> then calling update_rq_clock will trigger the WARN_DOUBLE_CLOCK warning. >> >> So we need to clear RQCF_UPDATED of rq->clock_update_flags synchronously >> to avoid the WARN_DOUBLE_CLOCK warning. >> >> Some call trace reports: >> Call Trace 1: >> <IRQ> >> sched_rt_period_timer+0x10f/0x3a0 >> ? enqueue_top_rt_rq+0x110/0x110 >> __hrtimer_run_queues+0x1a9/0x490 >> hrtimer_interrupt+0x10b/0x240 > > [...] > > For the sched_rt_period_timer() case you simply replace > raw_spin_rq_lock()/raw_spin_rq_unlock() with rq_lock()/rq_unlock(). > I.e. you're not using the new double_rq_clock_clear_update() which > is depicted in the text above. > Thanks for your review comments. Yes, adding this description would make it clearer. I will do it in patch v3. Thanks. >> Call Trace 2: >> <TASK> >> activate_task+0x8b/0x110 >> push_rt_task.part.108+0x241/0x2c0 >> push_rt_tasks+0x15/0x30 >> finish_task_switch+0xaa/0x2e0 >> ? __switch_to+0x134/0x420 >> __schedule+0x343/0x8e0 > > [...] > >> Call Trace 3: >> <TASK> >> deactivate_task+0x93/0xe0 >> pull_rt_task+0x33e/0x400 >> balance_rt+0x7e/0x90 >> __schedule+0x62f/0x8e0 >> do_task_dead+0x3f/0x50 > > [...] > >> Steps to reproduce: >> 1. Enable CONFIG_SCHED_DEBUG when compiling the kernel >> 2. echo 1 > /sys/kernel/debug/clear_warn_once >> echo "WARN_DOUBLE_CLOCK" > /sys/kernel/debug/sched_features > > s/sched_features/sched/features I will fix it in patch v3. Thanks. > >> echo "NO_RT_PUSH_IPI" > /sys/kernel/debug/sched_features > > s/sched_features/sched/features I will fix it in patch v3. Thanks. > >> 3. Run some rt tasks that periodically change the priority and sleep > > Not sure about the `change the priority` part? I'm using rt-app with 2*n > rt or dl (90% running) tasks (on a system with n CPUs) and can trigger > all of these cases. Yes, this problem is relatively easy to reproduce. I wrote a test case for rt scheduler to trigger all cases. I create 150 rt threads (my test environment has 96 cpus), change priority and sleep periodically. Constantly changing priorities in order to trigger push/pull_rt_task. void *ThreadFun(void *arg) { int cnt = *(int*)arg; struct sched_param param; while (1) { sqrt(MAGIC_NUM); cnt = cnt % 10 + 1; param.sched_priority = cnt; pthread_setschedparam(pthread_self(), SCHED_RR, ¶m); sqrt(MAGIC_NUM); sqrt(MAGIC_NUM); sleep(cnt); } return NULL; } I will try to reproduce again using rt-app, and will change the description of the reproduction steps in patch v3. Thanks. > >> Signed-off-by: Hao Jia <jiahao.os@bytedance.com> >> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> > > You can remove this Signed-off-by. I can provide a Reviewed-By for the > next version. OK, Thanks again for your review and suggestion, it really helped me. > > [...] > > When running PREEMPT_RT kernel there is another similar case in DL. > > [ 215.158100] ------------[ cut here ]------------ > [ 215.158105] rq->clock_update_flags & RQCF_UPDATED > [ 215.158113] WARNING: CPU: 2 PID: 1942 at kernel/sched/core.c:690 update_rq_clock+0x128/0x1a0 > ... > [ 215.158245] update_rq_clock+0x128/0x1a0 > [ 215.158253] migrate_task_rq_dl+0xec/0x310 <--- !!! > [ 215.158259] set_task_cpu+0x84/0x1e4 > [ 215.158264] try_to_wake_up+0x1d8/0x5c0 > [ 215.158268] wake_up_process+0x1c/0x30 > [ 215.158272] hrtimer_wakeup+0x24/0x3c > [ 215.158279] __hrtimer_run_queues+0x114/0x270 > [ 215.158285] hrtimer_interrupt+0xe8/0x244 > [ 215.158291] arch_timer_handler_phys+0x30/0x50 > [ 215.158301] handle_percpu_devid_irq+0x88/0x140 > [ 215.158306] generic_handle_domain_irq+0x40/0x60 > [ 215.158313] gic_handle_irq+0x48/0xe0 > [ 215.158320] call_on_irq_stack+0x2c/0x60 > [ 215.158327] do_interrupt_handler+0x80/0x84 > > For a non_contending task, this is the same issue as in sched_rt_period_timer(). > > -->8-- > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index cfe7b40bc4ff..668a9910cd6d 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -1804,6 +1804,7 @@ select_task_rq_dl(struct task_struct *p, int cpu, int flags) > > static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused) > { > + struct rq_flags rf; > struct rq *rq; > > if (READ_ONCE(p->__state) != TASK_WAKING) > @@ -1815,7 +1816,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused > * from try_to_wake_up(). Hence, p->pi_lock is locked, but > * rq->lock is not... So, lock it > */ > - raw_spin_rq_lock(rq); > + rq_lock(rq, &rf); > if (p->dl.dl_non_contending) { > update_rq_clock(rq); > sub_running_bw(&p->dl, &rq->dl); > @@ -1831,7 +1832,7 @@ static void migrate_task_rq_dl(struct task_struct *p, int new_cpu __maybe_unused > put_task_struct(p); > } > sub_rq_bw(&p->dl, &rq->dl); > - raw_spin_rq_unlock(rq); > + rq_unlock(rq, &rf); > } > I will fix it in patch v3. Thanks. ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task 2022-04-22 9:09 [PATCH v2 0/2] Avoid obvious double update_rq_clock warning Hao Jia 2022-04-22 9:09 ` [PATCH v2 1/2] sched/core: " Hao Jia @ 2022-04-22 9:09 ` Hao Jia 2022-04-25 16:21 ` Dietmar Eggemann 1 sibling, 1 reply; 7+ messages in thread From: Hao Jia @ 2022-04-22 9:09 UTC (permalink / raw) To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann, rostedt, bsegall, mgorman, bristot Cc: linux-kernel, Hao Jia The change to call update_rq_clock() before activate_task() commit 840d719604b0 ("sched/deadline: Update rq_clock of later_rq when pushing a task") is no longer needed since commit f4904815f97a ("sched/deadline: Fix double accounting of rq/running bw in push & pull") removed the add_running_bw() before the activate_task(). So we remove some comments that are no longer needed and update rq clock in activate_task(). Signed-off-by: Hao Jia <jiahao.os@bytedance.com> --- kernel/sched/deadline.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index fb4255ae0b2c..8eb694ed7ac1 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2319,13 +2319,7 @@ static int push_dl_task(struct rq *rq) deactivate_task(rq, next_task, 0); set_task_cpu(next_task, later_rq->cpu); - - /* - * Update the later_rq clock here, because the clock is used - * by the cpufreq_update_util() inside __add_running_bw(). - */ - update_rq_clock(later_rq); - activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); + activate_task(later_rq, next_task, 0); ret = 1; resched_curr(later_rq); -- 2.32.0 ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task 2022-04-22 9:09 ` [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task Hao Jia @ 2022-04-25 16:21 ` Dietmar Eggemann 2022-04-26 8:01 ` [External] " Hao Jia 0 siblings, 1 reply; 7+ messages in thread From: Dietmar Eggemann @ 2022-04-25 16:21 UTC (permalink / raw) To: Hao Jia, mingo, peterz, juri.lelli, vincent.guittot, rostedt, bsegall, mgorman, bristot Cc: linux-kernel On 22/04/2022 11:09, Hao Jia wrote: Nitpick: I would change the message slightly into something like: sched/deadline: Remove superfluous rq clock update in push_dl_task() > The change to call update_rq_clock() before activate_task() > commit 840d719604b0 ("sched/deadline: Update rq_clock of later_rq > when pushing a task") is no longer needed since commit f4904815f97a > ("sched/deadline: Fix double accounting of rq/running bw in push & pull") > removed the add_running_bw() before the activate_task(). > > So we remove some comments that are no longer needed and update > rq clock in activate_task(). > > Signed-off-by: Hao Jia <jiahao.os@bytedance.com> > --- > kernel/sched/deadline.c | 8 +------- > 1 file changed, 1 insertion(+), 7 deletions(-) > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > index fb4255ae0b2c..8eb694ed7ac1 100644 > --- a/kernel/sched/deadline.c > +++ b/kernel/sched/deadline.c > @@ -2319,13 +2319,7 @@ static int push_dl_task(struct rq *rq) > > deactivate_task(rq, next_task, 0); > set_task_cpu(next_task, later_rq->cpu); > - > - /* > - * Update the later_rq clock here, because the clock is used > - * by the cpufreq_update_util() inside __add_running_bw(). > - */ > - update_rq_clock(later_rq); > - activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); > + activate_task(later_rq, next_task, 0); > ret = 1; > > resched_curr(later_rq); Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [External] Re: [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task 2022-04-25 16:21 ` Dietmar Eggemann @ 2022-04-26 8:01 ` Hao Jia 0 siblings, 0 replies; 7+ messages in thread From: Hao Jia @ 2022-04-26 8:01 UTC (permalink / raw) To: Dietmar Eggemann, mingo, peterz, juri.lelli, vincent.guittot, rostedt, bsegall, mgorman, bristot Cc: linux-kernel On 2022/4/26 Dietmar Eggemann wrote: > On 22/04/2022 11:09, Hao Jia wrote: > > Nitpick: I would change the message slightly into something like: > > sched/deadline: Remove superfluous rq clock update in push_dl_task() > I will do it in patch v3. Thanks. >> The change to call update_rq_clock() before activate_task() >> commit 840d719604b0 ("sched/deadline: Update rq_clock of later_rq >> when pushing a task") is no longer needed since commit f4904815f97a >> ("sched/deadline: Fix double accounting of rq/running bw in push & pull") >> removed the add_running_bw() before the activate_task(). >> >> So we remove some comments that are no longer needed and update >> rq clock in activate_task(). >> >> Signed-off-by: Hao Jia <jiahao.os@bytedance.com> >> --- >> kernel/sched/deadline.c | 8 +------- >> 1 file changed, 1 insertion(+), 7 deletions(-) >> >> diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c >> index fb4255ae0b2c..8eb694ed7ac1 100644 >> --- a/kernel/sched/deadline.c >> +++ b/kernel/sched/deadline.c >> @@ -2319,13 +2319,7 @@ static int push_dl_task(struct rq *rq) >> >> deactivate_task(rq, next_task, 0); >> set_task_cpu(next_task, later_rq->cpu); >> - >> - /* >> - * Update the later_rq clock here, because the clock is used >> - * by the cpufreq_update_util() inside __add_running_bw(). >> - */ >> - update_rq_clock(later_rq); >> - activate_task(later_rq, next_task, ENQUEUE_NOCLOCK); >> + activate_task(later_rq, next_task, 0); >> ret = 1; >> >> resched_curr(later_rq); > > Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-04-26 8:01 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2022-04-22 9:09 [PATCH v2 0/2] Avoid obvious double update_rq_clock warning Hao Jia 2022-04-22 9:09 ` [PATCH v2 1/2] sched/core: " Hao Jia 2022-04-25 15:37 ` Dietmar Eggemann 2022-04-26 7:57 ` [External] " Hao Jia 2022-04-22 9:09 ` [PATCH v2 2/2] sched/dl: Remove some comments and adjust code in push_dl_task Hao Jia 2022-04-25 16:21 ` Dietmar Eggemann 2022-04-26 8:01 ` [External] " Hao Jia
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