<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/kernel/sched, branch v5.17.9</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>sched/pelt: Fix attach_entity_load_avg() corner case</title>
<updated>2022-04-27T12:41:12+00:00</updated>
<author>
<name>kuyo chang</name>
<email>kuyo.chang@mediatek.com</email>
</author>
<published>2022-04-14T09:02:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=cce88434d94d61911a2ac3cc795cd1323d36d720'/>
<id>cce88434d94d61911a2ac3cc795cd1323d36d720</id>
<content type='text'>
[ Upstream commit 40f5aa4c5eaebfeaca4566217cb9c468e28ed682 ]

The warning in cfs_rq_is_decayed() triggered:

    SCHED_WARN_ON(cfs_rq-&gt;avg.load_avg ||
		  cfs_rq-&gt;avg.util_avg ||
		  cfs_rq-&gt;avg.runnable_avg)

There exists a corner case in attach_entity_load_avg() which will
cause load_sum to be zero while load_avg will not be.

Consider se_weight is 88761 as per the sched_prio_to_weight[] table.
Further assume the get_pelt_divider() is 47742, this gives:
se-&gt;avg.load_avg is 1.

However, calculating load_sum:

  se-&gt;avg.load_sum = div_u64(se-&gt;avg.load_avg * se-&gt;avg.load_sum, se_weight(se));
  se-&gt;avg.load_sum = 1*47742/88761 = 0.

Then enqueue_load_avg() adds this to the cfs_rq totals:

  cfs_rq-&gt;avg.load_avg += se-&gt;avg.load_avg;
  cfs_rq-&gt;avg.load_sum += se_weight(se) * se-&gt;avg.load_sum;

Resulting in load_avg being 1 with load_sum is 0, which will trigger
the WARN.

Fixes: f207934fb79d ("sched/fair: Align PELT windows between cfs_rq and its se")
Signed-off-by: kuyo chang &lt;kuyo.chang@mediatek.com&gt;
[peterz: massage changelog]
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Tested-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Link: https://lkml.kernel.org/r/20220414090229.342-1-kuyo.chang@mediatek.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 40f5aa4c5eaebfeaca4566217cb9c468e28ed682 ]

The warning in cfs_rq_is_decayed() triggered:

    SCHED_WARN_ON(cfs_rq-&gt;avg.load_avg ||
		  cfs_rq-&gt;avg.util_avg ||
		  cfs_rq-&gt;avg.runnable_avg)

There exists a corner case in attach_entity_load_avg() which will
cause load_sum to be zero while load_avg will not be.

Consider se_weight is 88761 as per the sched_prio_to_weight[] table.
Further assume the get_pelt_divider() is 47742, this gives:
se-&gt;avg.load_avg is 1.

However, calculating load_sum:

  se-&gt;avg.load_sum = div_u64(se-&gt;avg.load_avg * se-&gt;avg.load_sum, se_weight(se));
  se-&gt;avg.load_sum = 1*47742/88761 = 0.

Then enqueue_load_avg() adds this to the cfs_rq totals:

  cfs_rq-&gt;avg.load_avg += se-&gt;avg.load_avg;
  cfs_rq-&gt;avg.load_sum += se_weight(se) * se-&gt;avg.load_sum;

Resulting in load_avg being 1 with load_sum is 0, which will trigger
the WARN.

Fixes: f207934fb79d ("sched/fair: Align PELT windows between cfs_rq and its se")
Signed-off-by: kuyo chang &lt;kuyo.chang@mediatek.com&gt;
[peterz: massage changelog]
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Tested-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Link: https://lkml.kernel.org/r/20220414090229.342-1-kuyo.chang@mediatek.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched: Teach the forced-newidle balancer about CPU affinity limitation.</title>
<updated>2022-04-13T17:27:42+00:00</updated>
<author>
<name>Sebastian Andrzej Siewior</name>
<email>bigeasy@linutronix.de</email>
</author>
<published>2022-03-17T14:51:32+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=46302d48f77dce2ecd244e5be82611a9b9361fc0'/>
<id>46302d48f77dce2ecd244e5be82611a9b9361fc0</id>
<content type='text'>
commit 386ef214c3c6ab111d05e1790e79475363abaa05 upstream.

try_steal_cookie() looks at task_struct::cpus_mask to decide if the
task could be moved to `this' CPU. It ignores that the task might be in
a migration disabled section while not on the CPU. In this case the task
must not be moved otherwise per-CPU assumption are broken.

Use is_cpu_allowed(), as suggested by Peter Zijlstra, to decide if the a
task can be moved.

Fixes: d2dfa17bc7de6 ("sched: Trivial forced-newidle balancer")
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/YjNK9El+3fzGmswf@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 386ef214c3c6ab111d05e1790e79475363abaa05 upstream.

try_steal_cookie() looks at task_struct::cpus_mask to decide if the
task could be moved to `this' CPU. It ignores that the task might be in
a migration disabled section while not on the CPU. In this case the task
must not be moved otherwise per-CPU assumption are broken.

Use is_cpu_allowed(), as suggested by Peter Zijlstra, to decide if the a
task can be moved.

Fixes: d2dfa17bc7de6 ("sched: Trivial forced-newidle balancer")
Signed-off-by: Sebastian Andrzej Siewior &lt;bigeasy@linutronix.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/YjNK9El+3fzGmswf@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/core: Fix forceidle balancing</title>
<updated>2022-04-13T17:27:42+00:00</updated>
<author>
<name>Peter Zijlstra</name>
<email>peterz@infradead.org</email>
</author>
<published>2022-03-16T21:03:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=68f4f6f6622c8673bdb43ec4621f8b49a670a430'/>
<id>68f4f6f6622c8673bdb43ec4621f8b49a670a430</id>
<content type='text'>
commit 5b6547ed97f4f5dfc23f8e3970af6d11d7b7ed7e upstream.

Steve reported that ChromeOS encounters the forceidle balancer being
ran from rt_mutex_setprio()'s balance_callback() invocation and
explodes.

Now, the forceidle balancer gets queued every time the idle task gets
selected, set_next_task(), which is strictly too often.
rt_mutex_setprio() also uses set_next_task() in the 'change' pattern:

	queued = task_on_rq_queued(p); /* p-&gt;on_rq == TASK_ON_RQ_QUEUED */
	running = task_current(rq, p); /* rq-&gt;curr == p */

	if (queued)
		dequeue_task(...);
	if (running)
		put_prev_task(...);

	/* change task properties */

	if (queued)
		enqueue_task(...);
	if (running)
		set_next_task(...);

However, rt_mutex_setprio() will explicitly not run this pattern on
the idle task (since priority boosting the idle task is quite insane).
Most other 'change' pattern users are pidhash based and would also not
apply to idle.

Also, the change pattern doesn't contain a __balance_callback()
invocation and hence we could have an out-of-band balance-callback,
which *should* trigger the WARN in rq_pin_lock() (which guards against
this exact anti-pattern).

So while none of that explains how this happens, it does indicate that
having it in set_next_task() might not be the most robust option.

Instead, explicitly queue the forceidle balancer from pick_next_task()
when it does indeed result in forceidle selection. Having it here,
ensures it can only be triggered under the __schedule() rq-&gt;lock
instance, and hence must be ran from that context.

This also happens to clean up the code a little, so win-win.

Fixes: d2dfa17bc7de ("sched: Trivial forced-newidle balancer")
Reported-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: T.J. Alumbaugh &lt;talumbau@chromium.org&gt;
Link: https://lkml.kernel.org/r/20220330160535.GN8939@worktop.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5b6547ed97f4f5dfc23f8e3970af6d11d7b7ed7e upstream.

Steve reported that ChromeOS encounters the forceidle balancer being
ran from rt_mutex_setprio()'s balance_callback() invocation and
explodes.

Now, the forceidle balancer gets queued every time the idle task gets
selected, set_next_task(), which is strictly too often.
rt_mutex_setprio() also uses set_next_task() in the 'change' pattern:

	queued = task_on_rq_queued(p); /* p-&gt;on_rq == TASK_ON_RQ_QUEUED */
	running = task_current(rq, p); /* rq-&gt;curr == p */

	if (queued)
		dequeue_task(...);
	if (running)
		put_prev_task(...);

	/* change task properties */

	if (queued)
		enqueue_task(...);
	if (running)
		set_next_task(...);

However, rt_mutex_setprio() will explicitly not run this pattern on
the idle task (since priority boosting the idle task is quite insane).
Most other 'change' pattern users are pidhash based and would also not
apply to idle.

Also, the change pattern doesn't contain a __balance_callback()
invocation and hence we could have an out-of-band balance-callback,
which *should* trigger the WARN in rq_pin_lock() (which guards against
this exact anti-pattern).

So while none of that explains how this happens, it does indicate that
having it in set_next_task() might not be the most robust option.

Instead, explicitly queue the forceidle balancer from pick_next_task()
when it does indeed result in forceidle selection. Having it here,
ensures it can only be triggered under the __schedule() rq-&gt;lock
instance, and hence must be ran from that context.

This also happens to clean up the code a little, so win-win.

Fixes: d2dfa17bc7de ("sched: Trivial forced-newidle balancer")
Reported-by: Steven Rostedt &lt;rostedt@goodmis.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: T.J. Alumbaugh &lt;talumbau@chromium.org&gt;
Link: https://lkml.kernel.org/r/20220330160535.GN8939@worktop.programming.kicks-ass.net
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/rt: Plug rt_mutex_setprio() vs push_rt_task() race</title>
<updated>2022-04-08T11:57:40+00:00</updated>
<author>
<name>Valentin Schneider</name>
<email>valentin.schneider@arm.com</email>
</author>
<published>2022-01-27T15:40:59+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=feedbfeb225c034043fd8a873d4cc44141d88c56'/>
<id>feedbfeb225c034043fd8a873d4cc44141d88c56</id>
<content type='text'>
[ Upstream commit 49bef33e4b87b743495627a529029156c6e09530 ]

John reported that push_rt_task() can end up invoking
find_lowest_rq(rq-&gt;curr) when curr is not an RT task (in this case a CFS
one), which causes mayhem down convert_prio().

This can happen when current gets demoted to e.g. CFS when releasing an
rt_mutex, and the local CPU gets hit with an rto_push_work irqwork before
getting the chance to reschedule. Exactly who triggers this work isn't
entirely clear to me - switched_from_rt() only invokes rt_queue_pull_task()
if there are no RT tasks on the local RQ, which means the local CPU can't
be in the rto_mask.

My current suspected sequence is something along the lines of the below,
with the demoted task being current.

  mark_wakeup_next_waiter()
    rt_mutex_adjust_prio()
      rt_mutex_setprio() // deboost originally-CFS task
	check_class_changed()
	  switched_from_rt() // Only rt_queue_pull_task() if !rq-&gt;rt.rt_nr_running
	  switched_to_fair() // Sets need_resched
      __balance_callbacks() // if pull_rt_task(), tell_cpu_to_push() can't select local CPU per the above
      raw_spin_rq_unlock(rq)

       // need_resched is set, so task_woken_rt() can't
       // invoke push_rt_tasks(). Best I can come up with is
       // local CPU has rt_nr_migratory &gt;= 2 after the demotion, so stays
       // in the rto_mask, and then:

       &lt;some other CPU running rto_push_irq_work_func() queues rto_push_work on this CPU&gt;
	 push_rt_task()
	   // breakage follows here as rq-&gt;curr is CFS

Move an existing check to check rq-&gt;curr vs the next pushable task's
priority before getting anywhere near find_lowest_rq(). While at it, add an
explicit sched_class of rq-&gt;curr check prior to invoking
find_lowest_rq(rq-&gt;curr). Align the DL logic to also reschedule regardless
of next_task's migratability.

Fixes: a7c81556ec4d ("sched: Fix migrate_disable() vs rt/dl balancing")
Reported-by: John Keeping &lt;john@metanate.com&gt;
Signed-off-by: Valentin Schneider &lt;valentin.schneider@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Tested-by: John Keeping &lt;john@metanate.com&gt;
Link: https://lore.kernel.org/r/20220127154059.974729-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 49bef33e4b87b743495627a529029156c6e09530 ]

John reported that push_rt_task() can end up invoking
find_lowest_rq(rq-&gt;curr) when curr is not an RT task (in this case a CFS
one), which causes mayhem down convert_prio().

This can happen when current gets demoted to e.g. CFS when releasing an
rt_mutex, and the local CPU gets hit with an rto_push_work irqwork before
getting the chance to reschedule. Exactly who triggers this work isn't
entirely clear to me - switched_from_rt() only invokes rt_queue_pull_task()
if there are no RT tasks on the local RQ, which means the local CPU can't
be in the rto_mask.

My current suspected sequence is something along the lines of the below,
with the demoted task being current.

  mark_wakeup_next_waiter()
    rt_mutex_adjust_prio()
      rt_mutex_setprio() // deboost originally-CFS task
	check_class_changed()
	  switched_from_rt() // Only rt_queue_pull_task() if !rq-&gt;rt.rt_nr_running
	  switched_to_fair() // Sets need_resched
      __balance_callbacks() // if pull_rt_task(), tell_cpu_to_push() can't select local CPU per the above
      raw_spin_rq_unlock(rq)

       // need_resched is set, so task_woken_rt() can't
       // invoke push_rt_tasks(). Best I can come up with is
       // local CPU has rt_nr_migratory &gt;= 2 after the demotion, so stays
       // in the rto_mask, and then:

       &lt;some other CPU running rto_push_irq_work_func() queues rto_push_work on this CPU&gt;
	 push_rt_task()
	   // breakage follows here as rq-&gt;curr is CFS

Move an existing check to check rq-&gt;curr vs the next pushable task's
priority before getting anywhere near find_lowest_rq(). While at it, add an
explicit sched_class of rq-&gt;curr check prior to invoking
find_lowest_rq(rq-&gt;curr). Align the DL logic to also reschedule regardless
of next_task's migratability.

Fixes: a7c81556ec4d ("sched: Fix migrate_disable() vs rt/dl balancing")
Reported-by: John Keeping &lt;john@metanate.com&gt;
Signed-off-by: Valentin Schneider &lt;valentin.schneider@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Dietmar Eggemann &lt;dietmar.eggemann@arm.com&gt;
Tested-by: John Keeping &lt;john@metanate.com&gt;
Link: https://lore.kernel.org/r/20220127154059.974729-1-valentin.schneider@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/cpuacct: Fix charge percpu cpuusage</title>
<updated>2022-04-08T11:57:40+00:00</updated>
<author>
<name>Chengming Zhou</name>
<email>zhouchengming@bytedance.com</email>
</author>
<published>2022-02-20T05:14:24+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ccd5b65aeea993b742f31893b868b5eaf08fbeec'/>
<id>ccd5b65aeea993b742f31893b868b5eaf08fbeec</id>
<content type='text'>
[ Upstream commit 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd ]

The cpuacct_account_field() is always called by the current task
itself, so it's ok to use __this_cpu_add() to charge the tick time.

But cpuacct_charge() maybe called by update_curr() in load_balance()
on a random CPU, different from the CPU on which the task is running.
So __this_cpu_add() will charge that cputime to a random incorrect CPU.

Fixes: 73e6aafd9ea8 ("sched/cpuacct: Simplify the cpuacct code")
Reported-by: Minye Zhu &lt;zhuminye@bytedance.com&gt;
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Link: https://lore.kernel.org/r/20220220051426.5274-1-zhouchengming@bytedance.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 248cc9993d1cc12b8e9ed716cc3fc09f6c3517dd ]

The cpuacct_account_field() is always called by the current task
itself, so it's ok to use __this_cpu_add() to charge the tick time.

But cpuacct_charge() maybe called by update_curr() in load_balance()
on a random CPU, different from the CPU on which the task is running.
So __this_cpu_add() will charge that cputime to a random incorrect CPU.

Fixes: 73e6aafd9ea8 ("sched/cpuacct: Simplify the cpuacct code")
Reported-by: Minye Zhu &lt;zhuminye@bytedance.com&gt;
Signed-off-by: Chengming Zhou &lt;zhouchengming@bytedance.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Tejun Heo &lt;tj@kernel.org&gt;
Link: https://lore.kernel.org/r/20220220051426.5274-1-zhouchengming@bytedance.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/fair: Improve consistency of allowed NUMA balance calculations</title>
<updated>2022-04-08T11:57:39+00:00</updated>
<author>
<name>Mel Gorman</name>
<email>mgorman@techsingularity.net</email>
</author>
<published>2022-02-08T09:43:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=38ab4d5d48866e01f4d6328e3be8d3cc18237257'/>
<id>38ab4d5d48866e01f4d6328e3be8d3cc18237257</id>
<content type='text'>
[ Upstream commit 2cfb7a1b031b0e816af7a6ee0c6ab83b0acdf05a ]

There are inconsistencies when determining if a NUMA imbalance is allowed
that should be corrected.

o allow_numa_imbalance changes types and is not always examining
  the destination group so both the type should be corrected as
  well as the naming.
o find_idlest_group uses the sched_domain's weight instead of the
  group weight which is different to find_busiest_group
o find_busiest_group uses the source group instead of the destination
  which is different to task_numa_find_cpu
o Both find_idlest_group and find_busiest_group should account
  for the number of running tasks if a move was allowed to be
  consistent with task_numa_find_cpu

Fixes: 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes")
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Link: https://lore.kernel.org/r/20220208094334.16379-2-mgorman@techsingularity.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2cfb7a1b031b0e816af7a6ee0c6ab83b0acdf05a ]

There are inconsistencies when determining if a NUMA imbalance is allowed
that should be corrected.

o allow_numa_imbalance changes types and is not always examining
  the destination group so both the type should be corrected as
  well as the naming.
o find_idlest_group uses the sched_domain's weight instead of the
  group weight which is different to find_busiest_group
o find_busiest_group uses the source group instead of the destination
  which is different to task_numa_find_cpu
o Both find_idlest_group and find_busiest_group should account
  for the number of running tasks if a move was allowed to be
  consistent with task_numa_find_cpu

Fixes: 7d2b5dd0bcc4 ("sched/numa: Allow a floating imbalance between NUMA nodes")
Signed-off-by: Mel Gorman &lt;mgorman@techsingularity.net&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Gautham R. Shenoy &lt;gautham.shenoy@amd.com&gt;
Link: https://lore.kernel.org/r/20220208094334.16379-2-mgorman@techsingularity.net
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/uclamp: Fix iowait boost escaping uclamp restriction</title>
<updated>2022-04-08T11:57:39+00:00</updated>
<author>
<name>Qais Yousef</name>
<email>qais.yousef@arm.com</email>
</author>
<published>2021-12-16T22:53:20+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=88e4d8c3cf083604e7e34f758100921a3367bf63'/>
<id>88e4d8c3cf083604e7e34f758100921a3367bf63</id>
<content type='text'>
[ Upstream commit d37aee9018e68b0d356195caefbb651910e0bbfa ]

iowait_boost signal is applied independently of util and doesn't take
into account uclamp settings of the rq. An io heavy task that is capped
by uclamp_max could still request higher frequency because
sugov_iowait_apply() doesn't clamp the boost via uclamp_rq_util_with()
like effective_cpu_util() does.

Make sure that iowait_boost honours uclamp requests by calling
uclamp_rq_util_with() when applying the boost.

Fixes: 982d9cdc22c9 ("sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Link: https://lore.kernel.org/r/20211216225320.2957053-3-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit d37aee9018e68b0d356195caefbb651910e0bbfa ]

iowait_boost signal is applied independently of util and doesn't take
into account uclamp settings of the rq. An io heavy task that is capped
by uclamp_max could still request higher frequency because
sugov_iowait_apply() doesn't clamp the boost via uclamp_rq_util_with()
like effective_cpu_util() does.

Make sure that iowait_boost honours uclamp requests by calling
uclamp_rq_util_with() when applying the boost.

Fixes: 982d9cdc22c9 ("sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
Link: https://lore.kernel.org/r/20211216225320.2957053-3-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/sugov: Ignore 'busy' filter when rq is capped by uclamp_max</title>
<updated>2022-04-08T11:57:39+00:00</updated>
<author>
<name>Qais Yousef</name>
<email>qais.yousef@arm.com</email>
</author>
<published>2021-12-16T22:53:19+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d9f51b85bfd88918951e157d5e8cd9a1b4ad6a25'/>
<id>d9f51b85bfd88918951e157d5e8cd9a1b4ad6a25</id>
<content type='text'>
[ Upstream commit 7a17e1db1265471f7718af100cfc5e41280d53a7 ]

sugov_update_single_{freq, perf}() contains a 'busy' filter that ensures
we don't bring the frqeuency down if there's no idle time (CPU is busy).

The problem is that with uclamp_max we will have scenarios where a busy
task is capped to run at a lower frequency and this filter prevents
applying the capping when this task starts running.

We handle this by skipping the filter when uclamp is enabled and the rq
is being capped by uclamp_max.

We introduce a new function uclamp_rq_is_capped() to help detecting when
this capping is taking effect. Some code shuffling was required to allow
using cpu_util_{cfs, rt}() in this new function.

On 2 Core SMT2 Intel laptop I see:

Without this patch:

	uclampset -M 0 sysbench --test=cpu --threads = 4 run

produces a score of ~3200 consistently. Which is the highest possible.

Compiling the kernel also results in frequency running at max 3.1GHz all
the time - running uclampset -M 400 to cap it has no effect without this
patch.

With this patch:

	uclampset -M 0 sysbench --test=cpu --threads = 4 run

produces a score of ~1100 with some outliers in ~1700. Uclamp max
aggregates the performance requirements, so having high values sometimes
is expected if some other task happens to require that frequency starts
running at the same time.

When compiling the kernel with uclampset -M 400 I can see the
frequencies mostly in the ~2GHz region. Helpful to conserve power and
prevent heating when not plugged in.

Fixes: 982d9cdc22c9 ("sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20211216225320.2957053-2-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 7a17e1db1265471f7718af100cfc5e41280d53a7 ]

sugov_update_single_{freq, perf}() contains a 'busy' filter that ensures
we don't bring the frqeuency down if there's no idle time (CPU is busy).

The problem is that with uclamp_max we will have scenarios where a busy
task is capped to run at a lower frequency and this filter prevents
applying the capping when this task starts running.

We handle this by skipping the filter when uclamp is enabled and the rq
is being capped by uclamp_max.

We introduce a new function uclamp_rq_is_capped() to help detecting when
this capping is taking effect. Some code shuffling was required to allow
using cpu_util_{cfs, rt}() in this new function.

On 2 Core SMT2 Intel laptop I see:

Without this patch:

	uclampset -M 0 sysbench --test=cpu --threads = 4 run

produces a score of ~3200 consistently. Which is the highest possible.

Compiling the kernel also results in frequency running at max 3.1GHz all
the time - running uclampset -M 400 to cap it has no effect without this
patch.

With this patch:

	uclampset -M 0 sysbench --test=cpu --threads = 4 run

produces a score of ~1100 with some outliers in ~1700. Uclamp max
aggregates the performance requirements, so having high values sometimes
is expected if some other task happens to require that frequency starts
running at the same time.

When compiling the kernel with uclampset -M 400 I can see the
frequencies mostly in the ~2GHz region. Helpful to conserve power and
prevent heating when not plugged in.

Fixes: 982d9cdc22c9 ("sched/cpufreq, sched/uclamp: Add clamps for FAIR and RT tasks")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20211216225320.2957053-2-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/core: Export pelt_thermal_tp</title>
<updated>2022-04-08T11:57:39+00:00</updated>
<author>
<name>Qais Yousef</name>
<email>qais.yousef@arm.com</email>
</author>
<published>2021-10-28T11:50:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=dd282f7aea3d5a10ea88d5aa1da651877ece8963'/>
<id>dd282f7aea3d5a10ea88d5aa1da651877ece8963</id>
<content type='text'>
[ Upstream commit 77cf151b7bbdfa3577b3c3f3a5e267a6c60a263b ]

We can't use this tracepoint in modules without having the symbol
exported first, fix that.

Fixes: 765047932f15 ("sched/pelt: Add support to track thermal pressure")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20211028115005.873539-1-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 77cf151b7bbdfa3577b3c3f3a5e267a6c60a263b ]

We can't use this tracepoint in modules without having the symbol
exported first, fix that.

Fixes: 765047932f15 ("sched/pelt: Add support to track thermal pressure")
Signed-off-by: Qais Yousef &lt;qais.yousef@arm.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20211028115005.873539-1-qais.yousef@arm.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/debug: Remove mpol_get/put and task_lock/unlock from sched_show_numa</title>
<updated>2022-04-08T11:57:39+00:00</updated>
<author>
<name>Bharata B Rao</name>
<email>bharata@amd.com</email>
</author>
<published>2022-01-18T05:05:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7d81adcaf441e26d33c85eb1b124980d5b06a09f'/>
<id>7d81adcaf441e26d33c85eb1b124980d5b06a09f</id>
<content type='text'>
[ Upstream commit 28c988c3ec29db74a1dda631b18785958d57df4f ]

The older format of /proc/pid/sched printed home node info which
required the mempolicy and task lock around mpol_get(). However
the format has changed since then and there is no need for
sched_show_numa() any more to have mempolicy argument,
asssociated mpol_get/put and task_lock/unlock. Remove them.

Fixes: 397f2378f1361 ("sched/numa: Fix numa balancing stats in /proc/pid/sched")
Signed-off-by: Bharata B Rao &lt;bharata@amd.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Link: https://lore.kernel.org/r/20220118050515.2973-1-bharata@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 28c988c3ec29db74a1dda631b18785958d57df4f ]

The older format of /proc/pid/sched printed home node info which
required the mempolicy and task lock around mpol_get(). However
the format has changed since then and there is no need for
sched_show_numa() any more to have mempolicy argument,
asssociated mpol_get/put and task_lock/unlock. Remove them.

Fixes: 397f2378f1361 ("sched/numa: Fix numa balancing stats in /proc/pid/sched")
Signed-off-by: Bharata B Rao &lt;bharata@amd.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Reviewed-by: Srikar Dronamraju &lt;srikar@linux.vnet.ibm.com&gt;
Acked-by: Mel Gorman &lt;mgorman@suse.de&gt;
Link: https://lore.kernel.org/r/20220118050515.2973-1-bharata@amd.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
