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1119 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Quentin Perret
|
449884aeb3 |
sched: Fix UCLAMP_FLAG_IDLE setting
[ Upstream commit ca4984a7dd863f3e1c0df775ae3e744bff24c303 ]
The UCLAMP_FLAG_IDLE flag is set on a runqueue when dequeueing the last
uclamp active task (that is, when buckets.tasks reaches 0 for all
buckets) to maintain the last uclamp.max and prevent blocked util from
suddenly becoming visible.
However, there is an asymmetry in how the flag is set and cleared which
can lead to having the flag set whilst there are active tasks on the rq.
Specifically, the flag is cleared in the uclamp_rq_inc() path, which is
called at enqueue time, but set in uclamp_rq_dec_id() which is called
both when dequeueing a task _and_ in the update_uclamp_active() path. As
a result, when both uclamp_rq_{dec,ind}_id() are called from
update_uclamp_active(), the flag ends up being set but not cleared,
hence leaving the runqueue in a broken state.
Fix this by clearing the flag in update_uclamp_active() as well.
Fixes:
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Qais Yousef
|
97f32c7f33 |
sched/uclamp: Fix uclamp_tg_restrict()
[ Upstream commit 0213b7083e81f4acd69db32cb72eb4e5f220329a ] Now cpu.uclamp.min acts as a protection, we need to make sure that the uclamp request of the task is within the allowed range of the cgroup, that is it is clamp()'ed correctly by tg->uclamp[UCLAMP_MIN] and tg->uclamp[UCLAMP_MAX]. As reported by Xuewen [1] we can have some corner cases where there's inversion between uclamp requested by task (p) and the uclamp values of the taskgroup it's attached to (tg). Following table demonstrates 2 corner cases: | p | tg | effective -----------+-----+------+----------- CASE 1 -----------+-----+------+----------- uclamp_min | 60% | 0% | 60% -----------+-----+------+----------- uclamp_max | 80% | 50% | 50% -----------+-----+------+----------- CASE 2 -----------+-----+------+----------- uclamp_min | 0% | 30% | 30% -----------+-----+------+----------- uclamp_max | 20% | 50% | 20% -----------+-----+------+----------- With this fix we get: | p | tg | effective -----------+-----+------+----------- CASE 1 -----------+-----+------+----------- uclamp_min | 60% | 0% | 50% -----------+-----+------+----------- uclamp_max | 80% | 50% | 50% -----------+-----+------+----------- CASE 2 -----------+-----+------+----------- uclamp_min | 0% | 30% | 30% -----------+-----+------+----------- uclamp_max | 20% | 50% | 30% -----------+-----+------+----------- Additionally uclamp_update_active_tasks() must now unconditionally update both UCLAMP_MIN/MAX because changing the tg's UCLAMP_MAX for instance could have an impact on the effective UCLAMP_MIN of the tasks. | p | tg | effective -----------+-----+------+----------- old -----------+-----+------+----------- uclamp_min | 60% | 0% | 50% -----------+-----+------+----------- uclamp_max | 80% | 50% | 50% -----------+-----+------+----------- *new* -----------+-----+------+----------- uclamp_min | 60% | 0% | *60%* -----------+-----+------+----------- uclamp_max | 80% |*70%* | *70%* -----------+-----+------+----------- [1] https://lore.kernel.org/lkml/CAB8ipk_a6VFNjiEnHRHkUMBKbA+qzPQvhtNjJ_YNzQhqV_o8Zw@mail.gmail.com/ Fixes: 0c18f2ecfcc2 ("sched/uclamp: Fix wrong implementation of cpu.uclamp.min") Reported-by: Xuewen Yan <xuewen.yan94@gmail.com> Signed-off-by: Qais Yousef <qais.yousef@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20210617165155.3774110-1-qais.yousef@arm.com Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Qais Yousef
|
8e5ffc1039 |
sched/uclamp: Fix locking around cpu_util_update_eff()
[ Upstream commit 93b73858701fd01de26a4a874eb95f9b7156fd4b ]
cpu_cgroup_css_online() calls cpu_util_update_eff() without holding the
uclamp_mutex or rcu_read_lock() like other call sites, which is
a mistake.
The uclamp_mutex is required to protect against concurrent reads and
writes that could update the cgroup hierarchy.
The rcu_read_lock() is required to traverse the cgroup data structures
in cpu_util_update_eff().
Surround the caller with the required locks and add some asserts to
better document the dependency in cpu_util_update_eff().
Fixes: 7226017ad37a ("sched/uclamp: Fix a bug in propagating uclamp value in new cgroups")
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210510145032.1934078-3-qais.yousef@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Qais Yousef
|
0b199ce65b |
sched/uclamp: Fix wrong implementation of cpu.uclamp.min
[ Upstream commit 0c18f2ecfcc274a4bcc1d122f79ebd4001c3b445 ]
cpu.uclamp.min is a protection as described in cgroup-v2 Resource
Distribution Model
Documentation/admin-guide/cgroup-v2.rst
which means we try our best to preserve the minimum performance point of
tasks in this group. See full description of cpu.uclamp.min in the
cgroup-v2.rst.
But the current implementation makes it a limit, which is not what was
intended.
For example:
tg->cpu.uclamp.min = 20%
p0->uclamp[UCLAMP_MIN] = 0
p1->uclamp[UCLAMP_MIN] = 50%
Previous Behavior (limit):
p0->effective_uclamp = 0
p1->effective_uclamp = 20%
New Behavior (Protection):
p0->effective_uclamp = 20%
p1->effective_uclamp = 50%
Which is inline with how protections should work.
With this change the cgroup and per-task behaviors are the same, as
expected.
Additionally, we remove the confusing relationship between cgroup and
!user_defined flag.
We don't want for example RT tasks that are boosted by default to max to
change their boost value when they attach to a cgroup. If a cgroup wants
to limit the max performance point of tasks attached to it, then
cpu.uclamp.max must be set accordingly.
Or if they want to set different boost value based on cgroup, then
sysctl_sched_util_clamp_min_rt_default must be used to NOT boost to max
and set the right cpu.uclamp.min for each group to let the RT tasks
obtain the desired boost value when attached to that group.
As it stands the dependency on !user_defined flag adds an extra layer of
complexity that is not required now cpu.uclamp.min behaves properly as
a protection.
The propagation model of effective cpu.uclamp.min in child cgroups as
implemented by cpu_util_update_eff() is still correct. The parent
protection sets an upper limit of what the child cgroups will
effectively get.
Fixes:
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Quentin Perret
|
687f523c13 |
sched: Fix out-of-bound access in uclamp
[ Upstream commit 6d2f8909a5fabb73fe2a63918117943986c39b6c ]
Util-clamp places tasks in different buckets based on their clamp values
for performance reasons. However, the size of buckets is currently
computed using a rounding division, which can lead to an off-by-one
error in some configurations.
For instance, with 20 buckets, the bucket size will be 1024/20=51. A
task with a clamp of 1024 will be mapped to bucket id 1024/51=20. Sadly,
correct indexes are in range [0,19], hence leading to an out of bound
memory access.
Clamp the bucket id to fix the issue.
Fixes:
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Juri Lelli
|
99d2926531 |
sched/features: Fix hrtick reprogramming
[ Upstream commit 156ec6f42b8d300dbbf382738ff35c8bad8f4c3a ]
Hung tasks and RCU stall cases were reported on systems which were not
100% busy. Investigation of such unexpected cases (no sign of potential
starvation caused by tasks hogging the system) pointed out that the
periodic sched tick timer wasn't serviced anymore after a certain point
and that caused all machinery that depends on it (timers, RCU, etc.) to
stop working as well. This issues was however only reproducible if
HRTICK was enabled.
Looking at core dumps it was found that the rbtree of the hrtimer base
used also for the hrtick was corrupted (i.e. next as seen from the base
root and actual leftmost obtained by traversing the tree are different).
Same base is also used for periodic tick hrtimer, which might get "lost"
if the rbtree gets corrupted.
Much alike what described in commit
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Thomas Gleixner
|
52f525f2bd |
sched: Reenable interrupts in do_sched_yield()
[ Upstream commit 345a957fcc95630bf5535d7668a59ed983eb49a7 ]
do_sched_yield() invokes schedule() with interrupts disabled which is
not allowed. This goes back to the pre git era to commit a6efb709806c
("[PATCH] irqlock patch 2.5.27-H6") in the history tree.
Reenable interrupts and remove the misleading comment which "explains" it.
Fixes:
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Juri Lelli
|
78e27678db |
sched/features: Fix !CONFIG_JUMP_LABEL case
[ Upstream commit a73f863af4ce9730795eab7097fb2102e6854365 ] Commit: |
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Sebastian Andrzej Siewior
|
644148cd15 |
workqueue: Remove the warning in wq_worker_sleeping()
[ Upstream commit 62849a9612924a655c67cf6962920544aa5c20db ]
The kernel test robot triggered a warning with the following race:
task-ctx A interrupt-ctx B
worker
-> process_one_work()
-> work_item()
-> schedule();
-> sched_submit_work()
-> wq_worker_sleeping()
-> ->sleeping = 1
atomic_dec_and_test(nr_running)
__schedule(); *interrupt*
async_page_fault()
-> local_irq_enable();
-> schedule();
-> sched_submit_work()
-> wq_worker_sleeping()
-> if (WARN_ON(->sleeping)) return
-> __schedule()
-> sched_update_worker()
-> wq_worker_running()
-> atomic_inc(nr_running);
-> ->sleeping = 0;
-> sched_update_worker()
-> wq_worker_running()
if (!->sleeping) return
In this context the warning is pointless everything is fine.
An interrupt before wq_worker_sleeping() will perform the ->sleeping
assignment (0 -> 1 > 0) twice.
An interrupt after wq_worker_sleeping() will trigger the warning and
nr_running will be decremented (by A) and incremented once (only by B, A
will skip it). This is the case until the ->sleeping is zeroed again in
wq_worker_running().
Remove the WARN statement because this condition may happen. Document
that preemption around wq_worker_sleeping() needs to be disabled to
protect ->sleeping and not just as an optimisation.
Fixes:
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Qais Yousef
|
2c0000f409 |
sched/uclamp: Fix a deadlock when enabling uclamp static key
[ Upstream commit e65855a52b479f98674998cb23b21ef5a8144b04 ]
The following splat was caught when setting uclamp value of a task:
BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:49
cpus_read_lock+0x68/0x130
static_key_enable+0x1c/0x38
__sched_setscheduler+0x900/0xad8
Fix by ensuring we enable the key outside of the critical section in
__sched_setscheduler()
Fixes: 46609ce22703 ("sched/uclamp: Protect uclamp fast path code with static key")
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200716110347.19553-4-qais.yousef@arm.com
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Qais Yousef
|
88435320eb |
sched/uclamp: Protect uclamp fast path code with static key
[ Upstream commit 46609ce227039fd192e0ecc7d940bed587fd2c78 ]
There is a report that when uclamp is enabled, a netperf UDP test
regresses compared to a kernel compiled without uclamp.
https://lore.kernel.org/lkml/20200529100806.GA3070@suse.de/
While investigating the root cause, there were no sign that the uclamp
code is doing anything particularly expensive but could suffer from bad
cache behavior under certain circumstances that are yet to be
understood.
https://lore.kernel.org/lkml/20200616110824.dgkkbyapn3io6wik@e107158-lin/
To reduce the pressure on the fast path anyway, add a static key that is
by default will skip executing uclamp logic in the
enqueue/dequeue_task() fast path until it's needed.
As soon as the user start using util clamp by:
1. Changing uclamp value of a task with sched_setattr()
2. Modifying the default sysctl_sched_util_clamp_{min, max}
3. Modifying the default cpu.uclamp.{min, max} value in cgroup
We flip the static key now that the user has opted to use util clamp.
Effectively re-introducing uclamp logic in the enqueue/dequeue_task()
fast path. It stays on from that point forward until the next reboot.
This should help minimize the effect of util clamp on workloads that
don't need it but still allow distros to ship their kernels with uclamp
compiled in by default.
SCHED_WARN_ON() in uclamp_rq_dec_id() was removed since now we can end
up with unbalanced call to uclamp_rq_dec_id() if we flip the key while
a task is running in the rq. Since we know it is harmless we just
quietly return if we attempt a uclamp_rq_dec_id() when
rq->uclamp[].bucket[].tasks is 0.
In schedutil, we introduce a new uclamp_is_enabled() helper which takes
the static key into account to ensure RT boosting behavior is retained.
The following results demonstrates how this helps on 2 Sockets Xeon E5
2x10-Cores system.
nouclamp uclamp uclamp-static-key
Hmean send-64 162.43 ( 0.00%) 157.84 * -2.82%* 163.39 * 0.59%*
Hmean send-128 324.71 ( 0.00%) 314.78 * -3.06%* 326.18 * 0.45%*
Hmean send-256 641.55 ( 0.00%) 628.67 * -2.01%* 648.12 * 1.02%*
Hmean send-1024 2525.28 ( 0.00%) 2448.26 * -3.05%* 2543.73 * 0.73%*
Hmean send-2048 4836.14 ( 0.00%) 4712.08 * -2.57%* 4867.69 * 0.65%*
Hmean send-3312 7540.83 ( 0.00%) 7425.45 * -1.53%* 7621.06 * 1.06%*
Hmean send-4096 9124.53 ( 0.00%) 8948.82 * -1.93%* 9276.25 * 1.66%*
Hmean send-8192 15589.67 ( 0.00%) 15486.35 * -0.66%* 15819.98 * 1.48%*
Hmean send-16384 26386.47 ( 0.00%) 25752.25 * -2.40%* 26773.74 * 1.47%*
The perf diff between nouclamp and uclamp-static-key when uclamp is
disabled in the fast path:
8.73% -1.55% [kernel.kallsyms] [k] try_to_wake_up
0.07% +0.04% [kernel.kallsyms] [k] deactivate_task
0.13% -0.02% [kernel.kallsyms] [k] activate_task
The diff between nouclamp and uclamp-static-key when uclamp is enabled
in the fast path:
8.73% -0.72% [kernel.kallsyms] [k] try_to_wake_up
0.13% +0.39% [kernel.kallsyms] [k] activate_task
0.07% +0.38% [kernel.kallsyms] [k] deactivate_task
Fixes:
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Qais Yousef
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047187eb0a |
sched/uclamp: Fix initialization of struct uclamp_rq
[ Upstream commit d81ae8aac85ca2e307d273f6dc7863a721bf054e ]
struct uclamp_rq was zeroed out entirely in assumption that in the first
call to uclamp_rq_inc() they'd be initialized correctly in accordance to
default settings.
But when next patch introduces a static key to skip
uclamp_rq_{inc,dec}() until userspace opts in to use uclamp, schedutil
will fail to perform any frequency changes because the
rq->uclamp[UCLAMP_MAX].value is zeroed at init and stays as such. Which
means all rqs are capped to 0 by default.
Fix it by making sure we do proper initialization at init without
relying on uclamp_rq_inc() doing it later.
Fixes:
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Mathieu Desnoyers
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b5b7749188 |
sched: Fix unreliable rseq cpu_id for new tasks
commit ce3614daabea8a2d01c1dd17ae41d1ec5e5ae7db upstream.
While integrating rseq into glibc and replacing glibc's sched_getcpu
implementation with rseq, glibc's tests discovered an issue with
incorrect __rseq_abi.cpu_id field value right after the first time
a newly created process issues sched_setaffinity.
For the records, it triggers after building glibc and running tests, and
then issuing:
for x in {1..2000} ; do posix/tst-affinity-static & done
and shows up as:
error: Unexpected CPU 2, expected 0
error: Unexpected CPU 2, expected 0
error: Unexpected CPU 2, expected 0
error: Unexpected CPU 2, expected 0
error: Unexpected CPU 138, expected 0
error: Unexpected CPU 138, expected 0
error: Unexpected CPU 138, expected 0
error: Unexpected CPU 138, expected 0
This is caused by the scheduler invoking __set_task_cpu() directly from
sched_fork() and wake_up_new_task(), thus bypassing rseq_migrate() which
is done by set_task_cpu().
Add the missing rseq_migrate() to both functions. The only other direct
use of __set_task_cpu() is done by init_idle(), which does not involve a
user-space task.
Based on my testing with the glibc test-case, just adding rseq_migrate()
to wake_up_new_task() is sufficient to fix the observed issue. Also add
it to sched_fork() to keep things consistent.
The reason why this never triggered so far with the rseq/basic_test
selftest is unclear.
The current use of sched_getcpu(3) does not typically require it to be
always accurate. However, use of the __rseq_abi.cpu_id field within rseq
critical sections requires it to be accurate. If it is not accurate, it
can cause corruption in the per-cpu data targeted by rseq critical
sections in user-space.
Reported-By: Florian Weimer <fweimer@redhat.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-By: Florian Weimer <fweimer@redhat.com>
Cc: stable@vger.kernel.org # v4.18+
Link: https://lkml.kernel.org/r/20200707201505.2632-1-mathieu.desnoyers@efficios.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Scott Wood
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1128ed7e1d |
sched/core: Check cpus_mask, not cpus_ptr in __set_cpus_allowed_ptr(), to fix mask corruption
[ Upstream commit fd844ba9ae59b51e34e77105d79f8eca780b3bd6 ] This function is concerned with the long-term CPU mask, not the transitory mask the task might have while migrate disabled. Before this patch, if a task was migrate-disabled at the time __set_cpus_allowed_ptr() was called, and the new mask happened to be equal to the CPU that the task was running on, then the mask update would be lost. Signed-off-by: Scott Wood <swood@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200617121742.cpxppyi7twxmpin7@linutronix.de Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Juri Lelli
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83bdf7f8b7 |
sched/core: Fix PI boosting between RT and DEADLINE tasks
[ Upstream commit 740797ce3a124b7dd22b7fb832d87bc8fba1cf6f ]
syzbot reported the following warning:
WARNING: CPU: 1 PID: 6351 at kernel/sched/deadline.c:628
enqueue_task_dl+0x22da/0x38a0 kernel/sched/deadline.c:1504
At deadline.c:628 we have:
623 static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
624 {
625 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
626 struct rq *rq = rq_of_dl_rq(dl_rq);
627
628 WARN_ON(dl_se->dl_boosted);
629 WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
[...]
}
Which means that setup_new_dl_entity() has been called on a task
currently boosted. This shouldn't happen though, as setup_new_dl_entity()
is only called when the 'dynamic' deadline of the new entity
is in the past w.r.t. rq_clock and boosted tasks shouldn't verify this
condition.
Digging through the PI code I noticed that what above might in fact happen
if an RT tasks blocks on an rt_mutex hold by a DEADLINE task. In the
first branch of boosting conditions we check only if a pi_task 'dynamic'
deadline is earlier than mutex holder's and in this case we set mutex
holder to be dl_boosted. However, since RT 'dynamic' deadlines are only
initialized if such tasks get boosted at some point (or if they become
DEADLINE of course), in general RT 'dynamic' deadlines are usually equal
to 0 and this verifies the aforementioned condition.
Fix it by checking that the potential donor task is actually (even if
temporary because in turn boosted) running at DEADLINE priority before
using its 'dynamic' deadline value.
Fixes:
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Huaixin Chang
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9fa3b0bd99 |
sched: Defend cfs and rt bandwidth quota against overflow
[ Upstream commit d505b8af58912ae1e1a211fabc9995b19bd40828 ] When users write some huge number into cpu.cfs_quota_us or cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of schedulable checks. to_ratio() could be altered to avoid unnecessary internal overflow, but min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to prevent overflow. Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Peter Zijlstra
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f7757368e0 |
sched/core: Fix illegal RCU from offline CPUs
[ Upstream commit bf2c59fce4074e55d622089b34be3a6bc95484fb ] In the CPU-offline process, it calls mmdrop() after idle entry and the subsequent call to cpuhp_report_idle_dead(). Once execution passes the call to rcu_report_dead(), RCU is ignoring the CPU, which results in lockdep complaining when mmdrop() uses RCU from either memcg or debugobjects below. Fix it by cleaning up the active_mm state from BP instead. Every arch which has CONFIG_HOTPLUG_CPU should have already called idle_task_exit() from AP. The only exception is parisc because it switches them to &init_mm unconditionally (see smp_boot_one_cpu() and smp_cpu_init()), but the patch will still work there because it calls mmgrab(&init_mm) in smp_cpu_init() and then should call mmdrop(&init_mm) in finish_cpu(). WARNING: suspicious RCU usage ----------------------------- kernel/workqueue.c:710 RCU or wq_pool_mutex should be held! other info that might help us debug this: RCU used illegally from offline CPU! Call Trace: dump_stack+0xf4/0x164 (unreliable) lockdep_rcu_suspicious+0x140/0x164 get_work_pool+0x110/0x150 __queue_work+0x1bc/0xca0 queue_work_on+0x114/0x120 css_release+0x9c/0xc0 percpu_ref_put_many+0x204/0x230 free_pcp_prepare+0x264/0x570 free_unref_page+0x38/0xf0 __mmdrop+0x21c/0x2c0 idle_task_exit+0x170/0x1b0 pnv_smp_cpu_kill_self+0x38/0x2e0 cpu_die+0x48/0x64 arch_cpu_idle_dead+0x30/0x50 do_idle+0x2f4/0x470 cpu_startup_entry+0x38/0x40 start_secondary+0x7a8/0xa80 start_secondary_resume+0x10/0x14 Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Qian Cai <cai@lca.pw> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Link: https://lkml.kernel.org/r/20200401214033.8448-1-cai@lca.pw Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Quentin Perret
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c04d01e918 |
sched/core: Fix reset-on-fork from RT with uclamp
commit eaf5a92ebde5bca3bb2565616115bd6d579486cd upstream.
uclamp_fork() resets the uclamp values to their default when the
reset-on-fork flag is set. It also checks whether the task has a RT
policy, and sets its uclamp.min to 1024 accordingly. However, during
reset-on-fork, the task's policy is lowered to SCHED_NORMAL right after,
hence leading to an erroneous uclamp.min setting for the new task if it
was forked from RT.
Fix this by removing the unnecessary check on rt_task() in
uclamp_fork() as this doesn't make sense if the reset-on-fork flag is
set.
Fixes:
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Scott Wood
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1dbfae0095 |
sched/core: Remove duplicate assignment in sched_tick_remote()
commit 82e0516ce3a147365a5dd2a9bedd5ba43a18663d upstream.
A redundant "curr = rq->curr" was added; remove it.
Fixes: ebc0f83c78a2 ("timers/nohz: Update NOHZ load in remote tick")
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/1580776558-12882-1-git-send-email-swood@redhat.com
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
||
|
Vincent Guittot
|
36b5fcc140 |
sched/fair: Prevent unlimited runtime on throttled group
[ Upstream commit 2a4b03ffc69f2dedc6388e9a6438b5f4c133a40d ]
When a running task is moved on a throttled task group and there is no
other task enqueued on the CPU, the task can keep running using 100% CPU
whatever the allocated bandwidth for the group and although its cfs rq is
throttled. Furthermore, the group entity of the cfs_rq and its parents are
not enqueued but only set as curr on their respective cfs_rqs.
We have the following sequence:
sched_move_task
-dequeue_task: dequeue task and group_entities.
-put_prev_task: put task and group entities.
-sched_change_group: move task to new group.
-enqueue_task: enqueue only task but not group entities because cfs_rq is
throttled.
-set_next_task : set task and group_entities as current sched_entity of
their cfs_rq.
Another impact is that the root cfs_rq runnable_load_avg at root rq stays
null because the group_entities are not enqueued. This situation will stay
the same until an "external" event triggers a reschedule. Let trigger it
immediately instead.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/1579011236-31256-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
||
|
Peter Zijlstra (Intel)
|
166d6008fa |
timers/nohz: Update NOHZ load in remote tick
[ Upstream commit ebc0f83c78a2d26384401ecf2d2fa48063c0ee27 ] The way loadavg is tracked during nohz only pays attention to the load upon entering nohz. This can be particularly noticeable if full nohz is entered while non-idle, and then the cpu goes idle and stays that way for a long time. Use the remote tick to ensure that full nohz cpus report their deltas within a reasonable time. [ swood: Added changelog and removed recheck of stopped tick. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Scott Wood <swood@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1578736419-14628-3-git-send-email-swood@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org> |
||
|
Scott Wood
|
5a309e3bf1 |
sched/core: Don't skip remote tick for idle CPUs
[ Upstream commit 488603b815a7514c7009e6fc339d74ed4a30f343 ] This will be used in the next patch to get a loadavg update from nohz cpus. The delta check is skipped because idle_sched_class doesn't update se.exec_start. Signed-off-by: Scott Wood <swood@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/1578736419-14628-2-git-send-email-swood@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org> |
||
|
Li Guanglei
|
5d13f62b9e |
sched/core: Fix size of rq::uclamp initialization
[ Upstream commit dcd6dffb0a75741471297724640733fa4e958d72 ]
rq::uclamp is an array of struct uclamp_rq, make sure we clear the
whole thing.
Fixes:
|
||
|
Qais Yousef
|
9f6f61c61a |
sched/uclamp: Reject negative values in cpu_uclamp_write()
commit b562d140649966d4daedd0483a8fe59ad3bb465a upstream.
The check to ensure that the new written value into cpu.uclamp.{min,max}
is within range, [0:100], wasn't working because of the signed
comparison
7301 if (req.percent > UCLAMP_PERCENT_SCALE) {
7302 req.ret = -ERANGE;
7303 return req;
7304 }
# echo -1 > cpu.uclamp.min
# cat cpu.uclamp.min
42949671.96
Cast req.percent into u64 to force the comparison to be unsigned and
work as intended in capacity_from_percent().
# echo -1 > cpu.uclamp.min
sh: write error: Numerical result out of range
Fixes:
|
||
|
Qais Yousef
|
ba95651cef |
sched/uclamp: Fix a bug in propagating uclamp value in new cgroups
commit 7226017ad37a888915628e59a84a2d1e57b40707 upstream.
When a new cgroup is created, the effective uclamp value wasn't updated
with a call to cpu_util_update_eff() that looks at the hierarchy and
update to the most restrictive values.
Fix it by ensuring to call cpu_util_update_eff() when a new cgroup
becomes online.
Without this change, the newly created cgroup uses the default
root_task_group uclamp values, which is 1024 for both uclamp_{min, max},
which will cause the rq to to be clamped to max, hence cause the
system to run at max frequency.
The problem was observed on Ubuntu server and was reproduced on Debian
and Buildroot rootfs.
By default, Ubuntu and Debian create a cpu controller cgroup hierarchy
and add all tasks to it - which creates enough noise to keep the rq
uclamp value at max most of the time. Imitating this behavior makes the
problem visible in Buildroot too which otherwise looks fine since it's a
minimal userspace.
Fixes:
|
||
|
Valentin Schneider
|
c598c8a46d |
sched/uclamp: Fix overzealous type replacement
[ Upstream commit 7763baace1b738d65efa46d68326c9406311c6bf ] Some uclamp helpers had their return type changed from 'unsigned int' to 'enum uclamp_id' by commit |
||
|
Qais Yousef
|
6e1ff0773f |
sched/uclamp: Fix incorrect condition
uclamp_update_active() should perform the update when
p->uclamp[clamp_id].active is true. But when the logic was inverted in
[1], the if condition wasn't inverted correctly too.
[1] https://lore.kernel.org/lkml/20190902073836.GO2369@hirez.programming.kicks-ass.net/
Reported-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Qais Yousef <qais.yousef@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Patrick Bellasi <patrick.bellasi@matbug.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes:
|
||
|
Peter Zijlstra
|
ff51ff84d8 |
sched/core: Avoid spurious lock dependencies
While seemingly harmless, __sched_fork() does hrtimer_init(), which,
when DEBUG_OBJETS, can end up doing allocations.
This then results in the following lock order:
rq->lock
zone->lock.rlock
batched_entropy_u64.lock
Which in turn causes deadlocks when we do wakeups while holding that
batched_entropy lock -- as the random code does.
Solve this by moving __sched_fork() out from under rq->lock. This is
safe because nothing there relies on rq->lock, as also evident from the
other __sched_fork() callsite.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akpm@linux-foundation.org
Cc: bigeasy@linutronix.de
Cc: cl@linux.com
Cc: keescook@chromium.org
Cc: penberg@kernel.org
Cc: rientjes@google.com
Cc: thgarnie@google.com
Cc: tytso@mit.edu
Cc: will@kernel.org
Fixes:
|
||
|
Peter Zijlstra
|
6e2df0581f |
sched: Fix pick_next_task() vs 'change' pattern race
Commit |
||
|
Qais Yousef
|
e3b8b6a0d1 |
sched/core: Fix compilation error when cgroup not selected
When cgroup is disabled the following compilation error was hit
kernel/sched/core.c: In function ‘uclamp_update_active_tasks’:
kernel/sched/core.c:1081:23: error: storage size of ‘it’ isn’t known
struct css_task_iter it;
^~
kernel/sched/core.c:1084:2: error: implicit declaration of function ‘css_task_iter_start’; did you mean ‘__sg_page_iter_start’? [-Werror=implicit-function-declaration]
css_task_iter_start(css, 0, &it);
^~~~~~~~~~~~~~~~~~~
__sg_page_iter_start
kernel/sched/core.c:1085:14: error: implicit declaration of function ‘css_task_iter_next’; did you mean ‘__sg_page_iter_next’? [-Werror=implicit-function-declaration]
while ((p = css_task_iter_next(&it))) {
^~~~~~~~~~~~~~~~~~
__sg_page_iter_next
kernel/sched/core.c:1091:2: error: implicit declaration of function ‘css_task_iter_end’; did you mean ‘get_task_cred’? [-Werror=implicit-function-declaration]
css_task_iter_end(&it);
^~~~~~~~~~~~~~~~~
get_task_cred
kernel/sched/core.c:1081:23: warning: unused variable ‘it’ [-Wunused-variable]
struct css_task_iter it;
^~
cc1: some warnings being treated as errors
make[2]: *** [kernel/sched/core.o] Error 1
Fix by protetion uclamp_update_active_tasks() with
CONFIG_UCLAMP_TASK_GROUP
Fixes:
|
||
|
Aleksa Sarai
|
dff3a85fec |
sched_setattr: switch to copy_struct_from_user()
Switch sched_setattr() syscall from it's own copying struct sched_attr
from userspace to the new dedicated copy_struct_from_user() helper.
The change is very straightforward, and helps unify the syscall
interface for struct-from-userspace syscalls. Ideally we could also
unify sched_getattr(2)-style syscalls as well, but unfortunately the
correct semantics for such syscalls are much less clear (see [1] for
more detail). In future we could come up with a more sane idea for how
the syscall interface should look.
[1]: commit
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Linus Torvalds
|
9c5efe9ae7 |
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar: - Apply a number of membarrier related fixes and cleanups, which fixes a use-after-free race in the membarrier code - Introduce proper RCU protection for tasks on the runqueue - to get rid of the subtle task_rcu_dereference() interface that was easy to get wrong - Misc fixes, but also an EAS speedup * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/fair: Avoid redundant EAS calculation sched/core: Remove double update_max_interval() call on CPU startup sched/core: Fix preempt_schedule() interrupt return comment sched/fair: Fix -Wunused-but-set-variable warnings sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr() sched/membarrier: Return -ENOMEM to userspace on memory allocation failure sched/membarrier: Skip IPIs when mm->mm_users == 1 selftests, sched/membarrier: Add multi-threaded test sched/membarrier: Fix p->mm->membarrier_state racy load sched/membarrier: Call sync_core only before usermode for same mm sched/membarrier: Remove redundant check sched/membarrier: Fix private expedited registration check tasks, sched/core: RCUify the assignment of rq->curr tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue tasks: Add a count of task RCU users sched/core: Convert vcpu_is_preempted() from macro to an inline function sched/fair: Remove unused cfs_rq_clock_task() function |
||
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Valentin Schneider
|
9fc41acc89 |
sched/core: Remove double update_max_interval() call on CPU startup
update_max_interval() is called in both CPUHP_AP_SCHED_STARTING's startup and teardown callbacks, but it turns out it's also called at the end of the startup callback of CPUHP_AP_ACTIVE (which is further down the startup sequence). There's no point in repeating this interval update in the startup sequence since the CPU will remain online until it goes down the teardown path. Remove the redundant call in sched_cpu_activate() (CPUHP_AP_ACTIVE). Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dietmar.eggemann@arm.com Cc: juri.lelli@redhat.com Cc: vincent.guittot@linaro.org Link: https://lkml.kernel.org/r/20190923093017.11755-1-valentin.schneider@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
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Valentin Schneider
|
a49b4f4012 |
sched/core: Fix preempt_schedule() interrupt return comment
preempt_schedule_irq() is the one that should be called on return from interrupt, clean up the comment to avoid any ambiguity. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-m68k@lists.linux-m68k.org Cc: linux-riscv@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Link: https://lkml.kernel.org/r/20190923143620.29334-2-valentin.schneider@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
KeMeng Shi
|
714e501e16 |
sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
An oops can be triggered in the scheduler when running qemu on arm64: Unable to handle kernel paging request at virtual address ffff000008effe40 Internal error: Oops: 96000007 [#1] SMP Process migration/0 (pid: 12, stack limit = 0x00000000084e3736) pstate: 20000085 (nzCv daIf -PAN -UAO) pc : __ll_sc___cmpxchg_case_acq_4+0x4/0x20 lr : move_queued_task.isra.21+0x124/0x298 ... Call trace: __ll_sc___cmpxchg_case_acq_4+0x4/0x20 __migrate_task+0xc8/0xe0 migration_cpu_stop+0x170/0x180 cpu_stopper_thread+0xec/0x178 smpboot_thread_fn+0x1ac/0x1e8 kthread+0x134/0x138 ret_from_fork+0x10/0x18 __set_cpus_allowed_ptr() will choose an active dest_cpu in affinity mask to migrage the process if process is not currently running on any one of the CPUs specified in affinity mask. __set_cpus_allowed_ptr() will choose an invalid dest_cpu (dest_cpu >= nr_cpu_ids, 1024 in my virtual machine) if CPUS in an affinity mask are deactived by cpu_down after cpumask_intersects check. cpumask_test_cpu() of dest_cpu afterwards is overflown and may pass if corresponding bit is coincidentally set. As a consequence, kernel will access an invalid rq address associate with the invalid CPU in migration_cpu_stop->__migrate_task->move_queued_task and the Oops occurs. The reproduce the crash: 1) A process repeatedly binds itself to cpu0 and cpu1 in turn by calling sched_setaffinity. 2) A shell script repeatedly does "echo 0 > /sys/devices/system/cpu/cpu1/online" and "echo 1 > /sys/devices/system/cpu/cpu1/online" in turn. 3) Oops appears if the invalid CPU is set in memory after tested cpumask. Signed-off-by: KeMeng Shi <shikemeng@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/1568616808-16808-1-git-send-email-shikemeng@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Mathieu Desnoyers
|
227a4aadc7 |
sched/membarrier: Fix p->mm->membarrier_state racy load
The membarrier_state field is located within the mm_struct, which is not guaranteed to exist when used from runqueue-lock-free iteration on runqueues by the membarrier system call. Copy the membarrier_state from the mm_struct into the scheduler runqueue when the scheduler switches between mm. When registering membarrier for mm, after setting the registration bit in the mm membarrier state, issue a synchronize_rcu() to ensure the scheduler observes the change. In order to take care of the case where a runqueue keeps executing the target mm without swapping to other mm, iterate over each runqueue and issue an IPI to copy the membarrier_state from the mm_struct into each runqueue which have the same mm which state has just been modified. Move the mm membarrier_state field closer to pgd in mm_struct to use a cache line already touched by the scheduler switch_mm. The membarrier_execve() (now membarrier_exec_mmap) hook now needs to clear the runqueue's membarrier state in addition to clear the mm membarrier state, so move its implementation into the scheduler membarrier code so it can access the runqueue structure. Add memory barrier in membarrier_exec_mmap() prior to clearing the membarrier state, ensuring memory accesses executed prior to exec are not reordered with the stores clearing the membarrier state. As suggested by Linus, move all membarrier.c RCU read-side locks outside of the for each cpu loops. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <efault@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190919173705.2181-5-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Eric W. Biederman
|
5311a98fef |
tasks, sched/core: RCUify the assignment of rq->curr
The current task on the runqueue is currently read with rcu_dereference(). To obtain ordinary RCU semantics for an rcu_dereference() of rq->curr it needs to be paired with rcu_assign_pointer() of rq->curr. Which provides the memory barrier necessary to order assignments to the task_struct and the assignment to rq->curr. Unfortunately the assignment of rq->curr in __schedule is a hot path, and it has already been show that additional barriers in that code will reduce the performance of the scheduler. So I will attempt to describe below why you can effectively have ordinary RCU semantics without any additional barriers. The assignment of rq->curr in init_idle is a slow path called once per cpu and that can use rcu_assign_pointer() without any concerns. As I write this there are effectively two users of rcu_dereference() on rq->curr. There is the membarrier code in kernel/sched/membarrier.c that only looks at "->mm" after the rcu_dereference(). Then there is task_numa_compare() in kernel/sched/fair.c. My best reading of the code shows that task_numa_compare only access: "->flags", "->cpus_ptr", "->numa_group", "->numa_faults[]", "->total_numa_faults", and "->se.cfs_rq". The code in __schedule() essentially does: rq_lock(...); smp_mb__after_spinlock(); next = pick_next_task(...); rq->curr = next; context_switch(prev, next); At the start of the function the rq_lock/smp_mb__after_spinlock pair provides a full memory barrier. Further there is a full memory barrier in context_switch(). This means that any task that has already run and modified itself (the common case) has already seen two memory barriers before __schedule() runs and begins executing. A task that modifies itself then sees a third full memory barrier pair with the rq_lock(); For a brand new task that is enqueued with wake_up_new_task() there are the memory barriers present from the taking and release the pi_lock and the rq_lock as the processes is enqueued as well as the full memory barrier at the start of __schedule() assuming __schedule() happens on the same cpu. This means that by the time we reach the assignment of rq->curr except for values on the task struct modified in pick_next_task the code has the same guarantees as if it used rcu_assign_pointer(). Reading through all of the implementations of pick_next_task it appears pick_next_task is limited to modifying the task_struct fields "->se", "->rt", "->dl". These fields are the sched_entity structures of the varies schedulers. Further "->se.cfs_rq" is only changed in cgroup attach/move operations initialized by userspace. Unless I have missed something this means that in practice that the users of "rcu_dereference(rq->curr)" get normal RCU semantics of rcu_dereference() for the fields the care about, despite the assignment of rq->curr in __schedule() ot using rcu_assign_pointer. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20190903200603.GW2349@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Eric W. Biederman
|
0ff7b2cfba |
tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue
In the ordinary case today the RCU grace period for a task_struct is triggered when another process wait's for it's zombine and causes the kernel to call release_task(). As the waiting task has to receive a signal and then act upon it before this happens, typically this will occur after the original task as been removed from the runqueue. Unfortunaty in some cases such as self reaping tasks it can be shown that release_task() will be called starting the grace period for task_struct long before the task leaves the runqueue. Therefore use put_task_struct_rcu_user() in finish_task_switch() to guarantee that the there is a RCU lifetime after the task leaves the runqueue. Besides the change in the start of the RCU grace period for the task_struct this change may cause perf_event_delayed_put and trace_sched_process_free. The function perf_event_delayed_put boils down to just a WARN_ON for cases that I assume never show happen. So I don't see any problem with delaying it. The function trace_sched_process_free is a trace point and thus visible to user space. Occassionally userspace has the strangest dependencies so this has a miniscule chance of causing a regression. This change only changes the timing of when the tracepoint is called. The change in timing arguably gives userspace a more accurate picture of what is going on. So I don't expect there to be a regression. In the case where a task self reaps we are pretty much guaranteed that the RCU grace period is delayed. So we should get quite a bit of coverage in of this worst case for the change in a normal threaded workload. So I expect any issues to turn up quickly or not at all. I have lightly tested this change and everything appears to work fine. Inspired-by: Linus Torvalds <torvalds@linux-foundation.org> Inspired-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Christoph Lameter <cl@linux.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux admin <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/87r24jdpl5.fsf_-_@x220.int.ebiederm.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Linus Torvalds
|
84da111de0 |
hmm related patches for 5.4
This is more cleanup and consolidation of the hmm APIs and the very
strongly related mmu_notifier interfaces. Many places across the tree
using these interfaces are touched in the process. Beyond that a cleanup
to the page walker API and a few memremap related changes round out the
series:
- General improvement of hmm_range_fault() and related APIs, more
documentation, bug fixes from testing, API simplification &
consolidation, and unused API removal
- Simplify the hmm related kconfigs to HMM_MIRROR and DEVICE_PRIVATE, and
make them internal kconfig selects
- Hoist a lot of code related to mmu notifier attachment out of drivers by
using a refcount get/put attachment idiom and remove the convoluted
mmu_notifier_unregister_no_release() and related APIs.
- General API improvement for the migrate_vma API and revision of its only
user in nouveau
- Annotate mmu_notifiers with lockdep and sleeping region debugging
Two series unrelated to HMM or mmu_notifiers came along due to
dependencies:
- Allow pagemap's memremap_pages family of APIs to work without providing
a struct device
- Make walk_page_range() and related use a constant structure for function
pointers
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Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull hmm updates from Jason Gunthorpe:
"This is more cleanup and consolidation of the hmm APIs and the very
strongly related mmu_notifier interfaces. Many places across the tree
using these interfaces are touched in the process. Beyond that a
cleanup to the page walker API and a few memremap related changes
round out the series:
- General improvement of hmm_range_fault() and related APIs, more
documentation, bug fixes from testing, API simplification &
consolidation, and unused API removal
- Simplify the hmm related kconfigs to HMM_MIRROR and DEVICE_PRIVATE,
and make them internal kconfig selects
- Hoist a lot of code related to mmu notifier attachment out of
drivers by using a refcount get/put attachment idiom and remove the
convoluted mmu_notifier_unregister_no_release() and related APIs.
- General API improvement for the migrate_vma API and revision of its
only user in nouveau
- Annotate mmu_notifiers with lockdep and sleeping region debugging
Two series unrelated to HMM or mmu_notifiers came along due to
dependencies:
- Allow pagemap's memremap_pages family of APIs to work without
providing a struct device
- Make walk_page_range() and related use a constant structure for
function pointers"
* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (75 commits)
libnvdimm: Enable unit test infrastructure compile checks
mm, notifier: Catch sleeping/blocking for !blockable
kernel.h: Add non_block_start/end()
drm/radeon: guard against calling an unpaired radeon_mn_unregister()
csky: add missing brackets in a macro for tlb.h
pagewalk: use lockdep_assert_held for locking validation
pagewalk: separate function pointers from iterator data
mm: split out a new pagewalk.h header from mm.h
mm/mmu_notifiers: annotate with might_sleep()
mm/mmu_notifiers: prime lockdep
mm/mmu_notifiers: add a lockdep map for invalidate_range_start/end
mm/mmu_notifiers: remove the __mmu_notifier_invalidate_range_start/end exports
mm/hmm: hmm_range_fault() infinite loop
mm/hmm: hmm_range_fault() NULL pointer bug
mm/hmm: fix hmm_range_fault()'s handling of swapped out pages
mm/mmu_notifiers: remove unregister_no_release
RDMA/odp: remove ib_ucontext from ib_umem
RDMA/odp: use mmu_notifier_get/put for 'struct ib_ucontext_per_mm'
RDMA/mlx5: Use odp instead of mr->umem in pagefault_mr
RDMA/mlx5: Use ib_umem_start instead of umem.address
...
|
||
|
Linus Torvalds
|
7f2444d38f |
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core timer updates from Thomas Gleixner:
"Timers and timekeeping updates:
- A large overhaul of the posix CPU timer code which is a preparation
for moving the CPU timer expiry out into task work so it can be
properly accounted on the task/process.
An update to the bogus permission checks will come later during the
merge window as feedback was not complete before heading of for
travel.
- Switch the timerqueue code to use cached rbtrees and get rid of the
homebrewn caching of the leftmost node.
- Consolidate hrtimer_init() + hrtimer_init_sleeper() calls into a
single function
- Implement the separation of hrtimers to be forced to expire in hard
interrupt context even when PREEMPT_RT is enabled and mark the
affected timers accordingly.
- Implement a mechanism for hrtimers and the timer wheel to protect
RT against priority inversion and live lock issues when a (hr)timer
which should be canceled is currently executing the callback.
Instead of infinitely spinning, the task which tries to cancel the
timer blocks on a per cpu base expiry lock which is held and
released by the (hr)timer expiry code.
- Enable the Hyper-V TSC page based sched_clock for Hyper-V guests
resulting in faster access to timekeeping functions.
- Updates to various clocksource/clockevent drivers and their device
tree bindings.
- The usual small improvements all over the place"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits)
posix-cpu-timers: Fix permission check regression
posix-cpu-timers: Always clear head pointer on dequeue
hrtimer: Add a missing bracket and hide `migration_base' on !SMP
posix-cpu-timers: Make expiry_active check actually work correctly
posix-timers: Unbreak CONFIG_POSIX_TIMERS=n build
tick: Mark sched_timer to expire in hard interrupt context
hrtimer: Add kernel doc annotation for HRTIMER_MODE_HARD
x86/hyperv: Hide pv_ops access for CONFIG_PARAVIRT=n
posix-cpu-timers: Utilize timerqueue for storage
posix-cpu-timers: Move state tracking to struct posix_cputimers
posix-cpu-timers: Deduplicate rlimit handling
posix-cpu-timers: Remove pointless comparisons
posix-cpu-timers: Get rid of 64bit divisions
posix-cpu-timers: Consolidate timer expiry further
posix-cpu-timers: Get rid of zero checks
rlimit: Rewrite non-sensical RLIMIT_CPU comment
posix-cpu-timers: Respect INFINITY for hard RTTIME limit
posix-cpu-timers: Switch thread group sampling to array
posix-cpu-timers: Restructure expiry array
posix-cpu-timers: Remove cputime_expires
...
|
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Linus Torvalds
|
7e67a85999 |
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- MAINTAINERS: Add Mark Rutland as perf submaintainer, Juri Lelli and
Vincent Guittot as scheduler submaintainers. Add Dietmar Eggemann,
Steven Rostedt, Ben Segall and Mel Gorman as scheduler reviewers.
As perf and the scheduler is getting bigger and more complex,
document the status quo of current responsibilities and interests,
and spread the review pain^H^H^H^H fun via an increase in the Cc:
linecount generated by scripts/get_maintainer.pl. :-)
- Add another series of patches that brings the -rt (PREEMPT_RT) tree
closer to mainline: split the monolithic CONFIG_PREEMPT dependencies
into a new CONFIG_PREEMPTION category that will allow the eventual
introduction of CONFIG_PREEMPT_RT. Still a few more hundred patches
to go though.
- Extend the CPU cgroup controller with uclamp.min and uclamp.max to
allow the finer shaping of CPU bandwidth usage.
- Micro-optimize energy-aware wake-ups from O(CPUS^2) to O(CPUS).
- Improve the behavior of high CPU count, high thread count
applications running under cpu.cfs_quota_us constraints.
- Improve balancing with SCHED_IDLE (SCHED_BATCH) tasks present.
- Improve CPU isolation housekeeping CPU allocation NUMA locality.
- Fix deadline scheduler bandwidth calculations and logic when cpusets
rebuilds the topology, or when it gets deadline-throttled while it's
being offlined.
- Convert the cpuset_mutex to percpu_rwsem, to allow it to be used from
setscheduler() system calls without creating global serialization.
Add new synchronization between cpuset topology-changing events and
the deadline acceptance tests in setscheduler(), which were broken
before.
- Rework the active_mm state machine to be less confusing and more
optimal.
- Rework (simplify) the pick_next_task() slowpath.
- Improve load-balancing on AMD EPYC systems.
- ... and misc cleanups, smaller fixes and improvements - please see
the Git log for more details.
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits)
sched/psi: Correct overly pessimistic size calculation
sched/fair: Speed-up energy-aware wake-ups
sched/uclamp: Always use 'enum uclamp_id' for clamp_id values
sched/uclamp: Update CPU's refcount on TG's clamp changes
sched/uclamp: Use TG's clamps to restrict TASK's clamps
sched/uclamp: Propagate system defaults to the root group
sched/uclamp: Propagate parent clamps
sched/uclamp: Extend CPU's cgroup controller
sched/topology: Improve load balancing on AMD EPYC systems
arch, ia64: Make NUMA select SMP
sched, perf: MAINTAINERS update, add submaintainers and reviewers
sched/fair: Use rq_lock/unlock in online_fair_sched_group
cpufreq: schedutil: fix equation in comment
sched: Rework pick_next_task() slow-path
sched: Allow put_prev_task() to drop rq->lock
sched/fair: Expose newidle_balance()
sched: Add task_struct pointer to sched_class::set_curr_task
sched: Rework CPU hotplug task selection
sched/{rt,deadline}: Fix set_next_task vs pick_next_task
sched: Fix kerneldoc comment for ia64_set_curr_task
...
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Linus Torvalds
|
94d18ee934 |
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:
"This cycle's RCU changes were:
- A few more RCU flavor consolidation cleanups.
- Updates to RCU's list-traversal macros improving lockdep usability.
- Forward-progress improvements for no-CBs CPUs: Avoid ignoring
incoming callbacks during grace-period waits.
- Forward-progress improvements for no-CBs CPUs: Use ->cblist
structure to take advantage of others' grace periods.
- Also added a small commit that avoids needlessly inflicting
scheduler-clock ticks on callback-offloaded CPUs.
- Forward-progress improvements for no-CBs CPUs: Reduce contention on
->nocb_lock guarding ->cblist.
- Forward-progress improvements for no-CBs CPUs: Add ->nocb_bypass
list to further reduce contention on ->nocb_lock guarding ->cblist.
- Miscellaneous fixes.
- Torture-test updates.
- minor LKMM updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (86 commits)
MAINTAINERS: Update from paulmck@linux.ibm.com to paulmck@kernel.org
rcu: Don't include <linux/ktime.h> in rcutiny.h
rcu: Allow rcu_do_batch() to dynamically adjust batch sizes
rcu/nocb: Don't wake no-CBs GP kthread if timer posted under overload
rcu/nocb: Reduce __call_rcu_nocb_wake() leaf rcu_node ->lock contention
rcu/nocb: Reduce nocb_cb_wait() leaf rcu_node ->lock contention
rcu/nocb: Advance CBs after merge in rcutree_migrate_callbacks()
rcu/nocb: Avoid synchronous wakeup in __call_rcu_nocb_wake()
rcu/nocb: Print no-CBs diagnostics when rcutorture writer unduly delayed
rcu/nocb: EXP Check use and usefulness of ->nocb_lock_contended
rcu/nocb: Add bypass callback queueing
rcu/nocb: Atomic ->len field in rcu_segcblist structure
rcu/nocb: Unconditionally advance and wake for excessive CBs
rcu/nocb: Reduce ->nocb_lock contention with separate ->nocb_gp_lock
rcu/nocb: Reduce contention at no-CBs invocation-done time
rcu/nocb: Reduce contention at no-CBs registry-time CB advancement
rcu/nocb: Round down for number of no-CBs grace-period kthreads
rcu/nocb: Avoid ->nocb_lock capture by corresponding CPU
rcu/nocb: Avoid needless wakeups of no-CBs grace-period kthread
rcu/nocb: Make __call_rcu_nocb_wake() safe for many callbacks
...
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Ingo Molnar
|
563c4f85f9 |
Merge branch 'sched/rt' into sched/core, to pick up -rt changes
Pick up the first couple of patches working towards PREEMPT_RT. Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Daniel Vetter
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312364f353 |
kernel.h: Add non_block_start/end()
In some special cases we must not block, but there's not a spinlock, preempt-off, irqs-off or similar critical section already that arms the might_sleep() debug checks. Add a non_block_start/end() pair to annotate these. This will be used in the oom paths of mmu-notifiers, where blocking is not allowed to make sure there's forward progress. Quoting Michal: "The notifier is called from quite a restricted context - oom_reaper - which shouldn't depend on any locks or sleepable conditionals. The code should be swift as well but we mostly do care about it to make a forward progress. Checking for sleepable context is the best thing we could come up with that would describe these demands at least partially." Peter also asked whether we want to catch spinlocks on top, but Michal said those are less of a problem because spinlocks can't have an indirect dependency upon the page allocator and hence close the loop with the oom reaper. Suggested by Michal Hocko. Link: https://lore.kernel.org/r/20190826201425.17547-4-daniel.vetter@ffwll.ch Acked-by: Christian König <christian.koenig@amd.com> (v1) Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> |
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Ingo Molnar
|
1251201c0d |
sched/core: Fix uclamp ABI bug, clean up and robustify sched_read_attr() ABI logic and code
Thadeu Lima de Souza Cascardo reported that 'chrt' broke on recent kernels: $ chrt -p $$ chrt: failed to get pid 26306's policy: Argument list too long and he has root-caused the bug to the following commit increasing sched_attr size and breaking sched_read_attr() into returning -EFBIG: |
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Patrick Bellasi
|
0413d7f33e |
sched/uclamp: Always use 'enum uclamp_id' for clamp_id values
The supported clamp indexes are defined in 'enum clamp_id', however, because of the code logic in some of the first utilization clamping series version, sometimes we needed to use 'unsigned int' to represent indices. This is not more required since the final version of the uclamp_* APIs can always use the proper enum uclamp_id type. Fix it with a bulk rename now that we have all the bits merged. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Michal Koutny <mkoutny@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190822132811.31294-7-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
|
babbe170e0 |
sched/uclamp: Update CPU's refcount on TG's clamp changes
On updates of task group (TG) clamp values, ensure that these new values are enforced on all RUNNABLE tasks of the task group, i.e. all RUNNABLE tasks are immediately boosted and/or capped as requested. Do that each time we update effective clamps from cpu_util_update_eff(). Use the *cgroup_subsys_state (css) to walk the list of tasks in each affected TG and update their RUNNABLE tasks. Update each task by using the same mechanism used for cpu affinity masks updates, i.e. by taking the rq lock. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Michal Koutny <mkoutny@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190822132811.31294-6-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
|
3eac870a32 |
sched/uclamp: Use TG's clamps to restrict TASK's clamps
When a task specific clamp value is configured via sched_setattr(2), this
value is accounted in the corresponding clamp bucket every time the task is
{en,de}qeued. However, when cgroups are also in use, the task specific
clamp values could be restricted by the task_group (TG) clamp values.
Update uclamp_cpu_inc() to aggregate task and TG clamp values. Every time a
task is enqueued, it's accounted in the clamp bucket tracking the smaller
clamp between the task specific value and its TG effective value. This
allows to:
1. ensure cgroup clamps are always used to restrict task specific requests,
i.e. boosted not more than its TG effective protection and capped at
least as its TG effective limit.
2. implement a "nice-like" policy, where tasks are still allowed to request
less than what enforced by their TG effective limits and protections
Do this by exploiting the concept of "effective" clamp, which is already
used by a TG to track parent enforced restrictions.
Apply task group clamp restrictions only to tasks belonging to a child
group. While, for tasks in the root group or in an autogroup, system
defaults are still enforced.
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Michal Koutny <mkoutny@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alessio Balsini <balsini@android.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Perret <quentin.perret@arm.com>
Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com>
Cc: Steve Muckle <smuckle@google.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Todd Kjos <tkjos@google.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lkml.kernel.org/r/20190822132811.31294-5-patrick.bellasi@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
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Patrick Bellasi
|
7274a5c1bb |
sched/uclamp: Propagate system defaults to the root group
The clamp values are not tunable at the level of the root task group. That's for two main reasons: - the root group represents "system resources" which are always entirely available from the cgroup standpoint. - when tuning/restricting "system resources" makes sense, tuning must be done using a system wide API which should also be available when control groups are not. When a system wide restriction is available, cgroups should be aware of its value in order to know exactly how much "system resources" are available for the subgroups. Utilization clamping supports already the concepts of: - system defaults: which define the maximum possible clamp values usable by tasks. - effective clamps: which allows a parent cgroup to constraint (maybe temporarily) its descendants without losing the information related to the values "requested" from them. Exploit these two concepts and bind them together in such a way that, whenever system default are tuned, the new values are propagated to (possibly) restrict or relax the "effective" value of nested cgroups. When cgroups are in use, force an update of all the RUNNABLE tasks. Otherwise, keep things simple and do just a lazy update next time each task will be enqueued. Do that since we assume a more strict resource control is required when cgroups are in use. This allows also to keep "effective" clamp values updated in case we need to expose them to user-space. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Michal Koutny <mkoutny@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190822132811.31294-4-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Patrick Bellasi
|
0b60ba2dd3 |
sched/uclamp: Propagate parent clamps
In order to properly support hierarchical resources control, the cgroup delegation model requires that attribute writes from a child group never fail but still are locally consistent and constrained based on parent's assigned resources. This requires to properly propagate and aggregate parent attributes down to its descendants. Implement this mechanism by adding a new "effective" clamp value for each task group. The effective clamp value is defined as the smaller value between the clamp value of a group and the effective clamp value of its parent. This is the actual clamp value enforced on tasks in a task group. Since it's possible for a cpu.uclamp.min value to be bigger than the cpu.uclamp.max value, ensure local consistency by restricting each "protection" (i.e. min utilization) with the corresponding "limit" (i.e. max utilization). Do that at effective clamps propagation to ensure all user-space write never fails while still always tracking the most restrictive values. Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Michal Koutny <mkoutny@suse.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: Alessio Balsini <balsini@android.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Joel Fernandes <joelaf@google.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Quentin Perret <quentin.perret@arm.com> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Steve Muckle <smuckle@google.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Todd Kjos <tkjos@google.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: https://lkml.kernel.org/r/20190822132811.31294-3-patrick.bellasi@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |