forked from luck/tmp_suning_uos_patched
41f1aed56d
3023 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Arnd Bergmann
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41f1aed56d |
smp: Fix smp_call_function_single_async prototype
commit 1139aeb1c521eb4a050920ce6c64c36c4f2a3ab7 upstream. As of commit |
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Waiman Long
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94f1bdf01b |
sched/debug: Fix cgroup_path[] serialization
[ Upstream commit ad789f84c9a145f8a18744c0387cec22ec51651e ]
The handling of sysrq key can be activated by echoing the key to
/proc/sysrq-trigger or via the magic key sequence typed into a terminal
that is connected to the system in some way (serial, USB or other mean).
In the former case, the handling is done in a user context. In the
latter case, it is likely to be in an interrupt context.
Currently in print_cpu() of kernel/sched/debug.c, sched_debug_lock is
taken with interrupt disabled for the whole duration of the calls to
print_*_stats() and print_rq() which could last for the quite some time
if the information dump happens on the serial console.
If the system has many cpus and the sched_debug_lock is somehow busy
(e.g. parallel sysrq-t), the system may hit a hard lockup panic
depending on the actually serial console implementation of the
system.
The purpose of sched_debug_lock is to serialize the use of the global
cgroup_path[] buffer in print_cpu(). The rests of the printk calls don't
need serialization from sched_debug_lock.
Calling printk() with interrupt disabled can still be problematic if
multiple instances are running. Allocating a stack buffer of PATH_MAX
bytes is not feasible because of the limited size of the kernel stack.
The solution implemented in this patch is to allow only one caller at a
time to use the full size group_path[], while other simultaneous callers
will have to use shorter stack buffers with the possibility of path
name truncation. A "..." suffix will be printed if truncation may have
happened. The cgroup path name is provided for informational purpose
only, so occasional path name truncation should not be a big problem.
Fixes:
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Valentin Schneider
|
80862cbf76 |
sched/fair: Fix shift-out-of-bounds in load_balance()
[ Upstream commit 39a2a6eb5c9b66ea7c8055026303b3aa681b49a5 ]
Syzbot reported a handful of occurrences where an sd->nr_balance_failed can
grow to much higher values than one would expect.
A successful load_balance() resets it to 0; a failed one increments
it. Once it gets to sd->cache_nice_tries + 3, this *should* trigger an
active balance, which will either set it to sd->cache_nice_tries+1 or reset
it to 0. However, in case the to-be-active-balanced task is not allowed to
run on env->dst_cpu, then the increment is done without any further
modification.
This could then be repeated ad nauseam, and would explain the absurdly high
values reported by syzbot (86, 149). VincentG noted there is value in
letting sd->cache_nice_tries grow, so the shift itself should be
fixed. That means preventing:
"""
If the value of the right operand is negative or is greater than or equal
to the width of the promoted left operand, the behavior is undefined.
"""
Thus we need to cap the shift exponent to
BITS_PER_TYPE(typeof(lefthand)) - 1.
I had a look around for other similar cases via coccinelle:
@expr@
position pos;
expression E1;
expression E2;
@@
(
E1 >> E2@pos
|
E1 >> E2@pos
)
@cst depends on expr@
position pos;
expression expr.E1;
constant cst;
@@
(
E1 >> cst@pos
|
E1 << cst@pos
)
@script:python depends on !cst@
pos << expr.pos;
exp << expr.E2;
@@
# Dirty hack to ignore constexpr
if exp.upper() != exp:
coccilib.report.print_report(pos[0], "Possible UB shift here")
The only other match in kernel/sched is rq_clock_thermal() which employs
sched_thermal_decay_shift, and that exponent is already capped to 10, so
that one is fine.
Fixes:
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Charan Teja Reddy
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a15f68a5d5 |
sched,psi: Handle potential task count underflow bugs more gracefully
[ Upstream commit 9d10a13d1e4c349b76f1c675a874a7f981d6d3b4 ] psi_group_cpu->tasks, represented by the unsigned int, stores the number of tasks that could be stalled on a psi resource(io/mem/cpu). Decrementing these counters at zero leads to wrapping which further leads to the psi_group_cpu->state_mask is being set with the respective pressure state. This could result into the unnecessary time sampling for the pressure state thus cause the spurious psi events. This can further lead to wrong actions being taken at the user land based on these psi events. Though psi_bug is set under these conditions but that just for debug purpose. Fix it by decrementing the ->tasks count only when it is non-zero. Signed-off-by: Charan Teja Reddy <charante@codeaurora.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lkml.kernel.org/r/1618585336-37219-1-git-send-email-charante@codeaurora.org Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Peter Zijlstra
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ae7fe4794d |
sched,fair: Alternative sched_slice()
[ Upstream commit 0c2de3f054a59f15e01804b75a04355c48de628c ] The current sched_slice() seems to have issues; there's two possible things that could be improved: - the 'nr_running' used for __sched_period() is daft when cgroups are considered. Using the RQ wide h_nr_running seems like a much more consistent number. - (esp) cgroups can slice it real fine, which makes for easy over-scheduling, ensure min_gran is what the name says. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Valentin Schneider <valentin.schneider@arm.com> Link: https://lkml.kernel.org/r/20210412102001.611897312@infradead.org Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Lingutla Chandrasekhar
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2f5f4cce49 |
sched/fair: Ignore percpu threads for imbalance pulls
[ Upstream commit 9bcb959d05eeb564dfc9cac13a59843a4fb2edf2 ]
During load balance, LBF_SOME_PINNED will be set if any candidate task
cannot be detached due to CPU affinity constraints. This can result in
setting env->sd->parent->sgc->group_imbalance, which can lead to a group
being classified as group_imbalanced (rather than any of the other, lower
group_type) when balancing at a higher level.
In workloads involving a single task per CPU, LBF_SOME_PINNED can often be
set due to per-CPU kthreads being the only other runnable tasks on any
given rq. This results in changing the group classification during
load-balance at higher levels when in reality there is nothing that can be
done for this affinity constraint: per-CPU kthreads, as the name implies,
don't get to move around (modulo hotplug shenanigans).
It's not as clear for userspace tasks - a task could be in an N-CPU cpuset
with N-1 offline CPUs, making it an "accidental" per-CPU task rather than
an intended one. KTHREAD_IS_PER_CPU gives us an indisputable signal which
we can leverage here to not set LBF_SOME_PINNED.
Note that the aforementioned classification to group_imbalance (when
nothing can be done) is especially problematic on big.LITTLE systems, which
have a topology the likes of:
DIE [ ]
MC [ ][ ]
0 1 2 3
L L B B
arch_scale_cpu_capacity(L) < arch_scale_cpu_capacity(B)
Here, setting LBF_SOME_PINNED due to a per-CPU kthread when balancing at MC
level on CPUs [0-1] will subsequently prevent CPUs [2-3] from classifying
the [0-1] group as group_misfit_task when balancing at DIE level. Thus, if
CPUs [0-1] are running CPU-bound (misfit) tasks, ill-timed per-CPU kthreads
can significantly delay the upgmigration of said misfit tasks. Systems
relying on ASYM_PACKING are likely to face similar issues.
Signed-off-by: Lingutla Chandrasekhar <clingutla@codeaurora.org>
[Use kthread_is_per_cpu() rather than p->nr_cpus_allowed]
[Reword changelog]
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lkml.kernel.org/r/20210407220628.3798191-2-valentin.schneider@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Vincent Donnefort
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661af9371c |
sched/pelt: Fix task util_est update filtering
[ Upstream commit b89997aa88f0b07d8a6414c908af75062103b8c9 ] Being called for each dequeue, util_est reduces the number of its updates by filtering out when the EWMA signal is different from the task util_avg by less than 1%. It is a problem for a sudden util_avg ramp-up. Due to the decay from a previous high util_avg, EWMA might now be close enough to the new util_avg. No update would then happen while it would leave ue.enqueued with an out-of-date value. Taking into consideration the two util_est members, EWMA and enqueued for the filtering, ensures, for both, an up-to-date value. This is for now an issue only for the trace probe that might return the stale value. Functional-wise, it isn't a problem, as the value is always accessed through max(enqueued, ewma). This problem has been observed using LISA's UtilConvergence:test_means on the sd845c board. No regression observed with Hackbench on sd845c and Perf-bench sched pipe on hikey/hikey960. Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lkml.kernel.org/r/20210225165820.1377125-1-vincent.donnefort@arm.com Signed-off-by: Sasha Levin <sashal@kernel.org> |
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Mathieu Desnoyers
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68b4378d91 |
sched/membarrier: fix missing local execution of ipi_sync_rq_state()
commit ce29ddc47b91f97e7f69a0fb7cbb5845f52a9825 upstream.
The function sync_runqueues_membarrier_state() should copy the
membarrier state from the @mm received as parameter to each runqueue
currently running tasks using that mm.
However, the use of smp_call_function_many() skips the current runqueue,
which is unintended. Replace by a call to on_each_cpu_mask().
Fixes:
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Juri Lelli
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9a68fa0ebb |
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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Peter Zijlstra
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6816509065 |
sched/core: Allow try_invoke_on_locked_down_task() with irqs disabled
commit 1b7af295541d75535374325fd617944534853919 upstream. The try_invoke_on_locked_down_task() function currently requires that interrupts be enabled, but it is called with interrupts disabled from rcu_print_task_stall(), resulting in an "IRQs not enabled as expected" diagnostic. This commit therefore updates try_invoke_on_locked_down_task() to use raw_spin_lock_irqsave() instead of raw_spin_lock_irq(), thus allowing use from either context. Link: https://lore.kernel.org/lkml/000000000000903d5805ab908fc4@google.com/ Link: https://lore.kernel.org/lkml/20200928075729.GC2611@hirez.programming.kicks-ass.net/ Reported-by: syzbot+cb3b69ae80afd6535b0e@syzkaller.appspotmail.com Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Frederic Weisbecker
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e713bdd791 |
rcu/nocb: Perform deferred wake up before last idle's need_resched() check
commit 43789ef3f7d61aa7bed0cb2764e588fc990c30ef upstream.
Entering RCU idle mode may cause a deferred wake up of an RCU NOCB_GP
kthread (rcuog) to be serviced.
Usually a local wake up happening while running the idle task is handled
in one of the need_resched() checks carefully placed within the idle
loop that can break to the scheduler.
Unfortunately the call to rcu_idle_enter() is already beyond the last
generic need_resched() check and we may halt the CPU with a resched
request unhandled, leaving the task hanging.
Fix this with splitting the rcuog wakeup handling from rcu_idle_enter()
and place it before the last generic need_resched() check in the idle
loop. It is then assumed that no call to call_rcu() will be performed
after that in the idle loop until the CPU is put in low power mode.
Fixes:
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Qais Yousef
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91e10f2ad1 |
sched/eas: Don't update misfit status if the task is pinned
[ Upstream commit 0ae78eec8aa64e645866e75005162603a77a0f49 ]
If the task is pinned to a cpu, setting the misfit status means that
we'll unnecessarily continuously attempt to migrate the task but fail.
This continuous failure will cause the balance_interval to increase to
a high value, and eventually cause unnecessary significant delays in
balancing the system when real imbalance happens.
Caught while testing uclamp where rt-app calibration loop was pinned to
cpu 0, shortly after which we spawn another task with high util_clamp
value. The task was failing to migrate after over 40ms of runtime due to
balance_interval unnecessary expanded to a very high value from the
calibration loop.
Not done here, but it could be useful to extend the check for pinning to
verify that the affinity of the task has a cpu that fits. We could end
up in a similar situation otherwise.
Fixes:
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Xuewen Yan
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e830af503c |
sched/fair: Avoid stale CPU util_est value for schedutil in task dequeue
[ Upstream commit 8c1f560c1ea3f19e22ba356f62680d9d449c9ec2 ]
CPU (root cfs_rq) estimated utilization (util_est) is currently used in
dequeue_task_fair() to drive frequency selection before it is updated.
with:
CPU_util : rq->cfs.avg.util_avg
CPU_util_est : rq->cfs.avg.util_est
CPU_utilization : max(CPU_util, CPU_util_est)
task_util : p->se.avg.util_avg
task_util_est : p->se.avg.util_est
dequeue_task_fair():
/* (1) CPU_util and task_util update + inform schedutil about
CPU_utilization changes */
for_each_sched_entity() /* 2 loops */
(dequeue_entity() ->) update_load_avg() -> cfs_rq_util_change()
-> cpufreq_update_util() ->...-> sugov_update_[shared\|single]
-> sugov_get_util() -> cpu_util_cfs()
/* (2) CPU_util_est and task_util_est update */
util_est_dequeue()
cpu_util_cfs() uses CPU_utilization which could lead to a false (too
high) utilization value for schedutil in task ramp-down or ramp-up
scenarios during task dequeue.
To mitigate the issue split the util_est update (2) into:
(A) CPU_util_est update in util_est_dequeue()
(B) task_util_est update in util_est_update()
Place (A) before (1) and keep (B) where (2) is. The latter is necessary
since (B) relies on task_util update in (1).
Fixes:
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Thomas Gleixner
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8933a52534 |
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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Peng Liu
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6d4250fe7d |
sched/deadline: Fix sched_dl_global_validate()
[ Upstream commit a57415f5d1e43c3a5c5d412cd85e2792d7ed9b11 ]
When change sched_rt_{runtime, period}_us, we validate that the new
settings should at least accommodate the currently allocated -dl
bandwidth:
sched_rt_handler()
--> sched_dl_bandwidth_validate()
{
new_bw = global_rt_runtime()/global_rt_period();
for_each_possible_cpu(cpu) {
dl_b = dl_bw_of(cpu);
if (new_bw < dl_b->total_bw) <-------
ret = -EBUSY;
}
}
But under CONFIG_SMP, dl_bw is per root domain , but not per CPU,
dl_b->total_bw is the allocated bandwidth of the whole root domain.
Instead, we should compare dl_b->total_bw against "cpus*new_bw",
where 'cpus' is the number of CPUs of the root domain.
Also, below annotation(in kernel/sched/sched.h) implied implementation
only appeared in SCHED_DEADLINE v2[1], then deadline scheduler kept
evolving till got merged(v9), but the annotation remains unchanged,
meaningless and misleading, update it.
* With respect to SMP, the bandwidth is given on a per-CPU basis,
* meaning that:
* - dl_bw (< 100%) is the bandwidth of the system (group) on each CPU;
* - dl_total_bw array contains, in the i-eth element, the currently
* allocated bandwidth on the i-eth CPU.
[1]: https://lore.kernel.org/lkml/1267385230.13676.101.camel@Palantir/
Fixes:
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Andy Lutomirski
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e45cdc71d1 |
membarrier: Execute SYNC_CORE on the calling thread
membarrier()'s MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE is documented as
syncing the core on all sibling threads but not necessarily the calling
thread. This behavior is fundamentally buggy and cannot be used safely.
Suppose a user program has two threads. Thread A is on CPU 0 and thread B
is on CPU 1. Thread A modifies some text and calls
membarrier(MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE).
Then thread B executes the modified code. If, at any point after
membarrier() decides which CPUs to target, thread A could be preempted and
replaced by thread B on CPU 0. This could even happen on exit from the
membarrier() syscall. If this happens, thread B will end up running on CPU
0 without having synced.
In principle, this could be fixed by arranging for the scheduler to issue
sync_core_before_usermode() whenever switching between two threads in the
same mm if there is any possibility of a concurrent membarrier() call, but
this would have considerable overhead. Instead, make membarrier() sync the
calling CPU as well.
As an optimization, this avoids an extra smp_mb() in the default
barrier-only mode and an extra rseq preempt on the caller.
Fixes:
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Andy Lutomirski
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758c9373d8 |
membarrier: Explicitly sync remote cores when SYNC_CORE is requested
membarrier() does not explicitly sync_core() remote CPUs; instead, it
relies on the assumption that an IPI will result in a core sync. On x86,
this may be true in practice, but it's not architecturally reliable. In
particular, the SDM and APM do not appear to guarantee that interrupt
delivery is serializing. While IRET does serialize, IPI return can
schedule, thereby switching to another task in the same mm that was
sleeping in a syscall. The new task could then SYSRET back to usermode
without ever executing IRET.
Make this more robust by explicitly calling sync_core_before_usermode()
on remote cores. (This also helps people who search the kernel tree for
instances of sync_core() and sync_core_before_usermode() -- one might be
surprised that the core membarrier code doesn't currently show up in a
such a search.)
Fixes:
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Andy Lutomirski
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2ecedd7569 |
membarrier: Add an actual barrier before rseq_preempt()
It seems that most RSEQ membarrier users will expect any stores done before
the membarrier() syscall to be visible to the target task(s). While this
is extremely likely to be true in practice, nothing actually guarantees it
by a strict reading of the x86 manuals. Rather than providing this
guarantee by accident and potentially causing a problem down the road, just
add an explicit barrier.
Fixes:
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Linus Torvalds
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f91a3aa6bc |
Yet two more places which invoke tracing from RCU disabled regions in the
idle path. Similar to the entry path the low level idle functions have to be non-instrumentable. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEQp8+kY+LLUocC4bMphj1TA10mKEFAl/DpAUTHHRnbHhAbGlu dXRyb25peC5kZQAKCRCmGPVMDXSYoXSLD/9klc0YimnEnROW6Q5Svb2IcyIutmXF bOIY1bYYoKILOBj3wyvDUhmdMuq5zh7H9yG11hO8MaVVWVQcLcOMLdHTYm9dcdmF xQk33+xqjuhRShB+nEmC9ayYtWogtH6W6uZ6WDtF9ZltMKU85n5ddGJ/Fvo+HoCb NbOdHGJdJ3/3ZCeHnxOnxM+5/GwjkBuccTV/tXmb3yXrfU9DBySyQ4/UchcpF43w LcEb0kiQbpZsBTByKJOQV8+RR654S0sILlvRwVXpmj94vrgGwhlVk1/9rz7tkOhF ksoo1mTVu75LMt22G/hXxE63787yRvFdHjapf0+kCOAuhl992NK+xlGDH8o9DXcu 9y73D4bI0HnDFs20w6vs20iLvxECJiYHJqlgR5ZwFUToceaNgtiYr8kzuD7Zbae1 KG2E7BuNSwHWMtf97fGn44GZknPEOaKdDn4Wv6/bvKHxLm77qe11RKF70Stcz2AI am13KmQzzsHGF5qNWwpElRUxSdxfJMR66RnOdTQULGrRedaZTFol/y2pnVzTSe3k SZnlpL5kE7y92UYDogPb5wWA7b+YkJN0OdSkRFy1FH26ZG8E4M7ZJ2tql5Sw7pGM lsTjXpAUphnK5rz7QcYE8KAZWj//fIAcElIrvdklVcBnS3IqjfksYW27B64133vx cT1B/lA1PHXj6Q== =raED -----END PGP SIGNATURE----- Merge tag 'locking-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Thomas Gleixner: "Two more places which invoke tracing from RCU disabled regions in the idle path. Similar to the entry path the low level idle functions have to be non-instrumentable" * tag 'locking-urgent-2020-11-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: intel_idle: Fix intel_idle() vs tracing sched/idle: Fix arch_cpu_idle() vs tracing |
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Peter Zijlstra
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58c644ba51 |
sched/idle: Fix arch_cpu_idle() vs tracing
We call arch_cpu_idle() with RCU disabled, but then use
local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
Switch all arch_cpu_idle() implementations to use
raw_local_irq_{en,dis}able() and carefully manage the
lockdep,rcu,tracing state like we do in entry.
(XXX: we really should change arch_cpu_idle() to not return with
interrupts enabled)
Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lkml.kernel.org/r/20201120114925.594122626@infradead.org
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Linus Torvalds
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f4b936f5d6 |
A couple of scheduler fixes:
- Make the conditional update of the overutilized state work correctly by
caching the relevant flags state before overwriting them and checking
them afterwards.
- Fix a data race in the wakeup path which caused loadavg on ARM64
platforms to become a random number generator.
- Fix the ordering of the iowaiter accounting operations so it can't be
decremented before it is incremented.
- Fix a bug in the deadline scheduler vs. priority inheritance when a
non-deadline task A has inherited the parameters of a deadline task B
and then blocks on a non-deadline task C.
The second inheritance step used the static deadline parameters of task
A, which are usually 0, instead of further propagating task B's
parameters. The zero initialized parameters trigger a bug in the
deadline scheduler.
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Merge tag 'sched-urgent-2020-11-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
"A couple of scheduler fixes:
- Make the conditional update of the overutilized state work
correctly by caching the relevant flags state before overwriting
them and checking them afterwards.
- Fix a data race in the wakeup path which caused loadavg on ARM64
platforms to become a random number generator.
- Fix the ordering of the iowaiter accounting operations so it can't
be decremented before it is incremented.
- Fix a bug in the deadline scheduler vs. priority inheritance when a
non-deadline task A has inherited the parameters of a deadline task
B and then blocks on a non-deadline task C.
The second inheritance step used the static deadline parameters of
task A, which are usually 0, instead of further propagating task
B's parameters. The zero initialized parameters trigger a bug in
the deadline scheduler"
* tag 'sched-urgent-2020-11-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Fix priority inheritance with multiple scheduling classes
sched: Fix rq->nr_iowait ordering
sched: Fix data-race in wakeup
sched/fair: Fix overutilized update in enqueue_task_fair()
|
||
|
Juri Lelli
|
2279f540ea |
sched/deadline: Fix priority inheritance with multiple scheduling classes
Glenn reported that "an application [he developed produces] a BUG in deadline.c when a SCHED_DEADLINE task contends with CFS tasks on nested PTHREAD_PRIO_INHERIT mutexes. I believe the bug is triggered when a CFS task that was boosted by a SCHED_DEADLINE task boosts another CFS task (nested priority inheritance). ------------[ cut here ]------------ kernel BUG at kernel/sched/deadline.c:1462! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 12 PID: 19171 Comm: dl_boost_bug Tainted: ... Hardware name: ... RIP: 0010:enqueue_task_dl+0x335/0x910 Code: ... RSP: 0018:ffffc9000c2bbc68 EFLAGS: 00010002 RAX: 0000000000000009 RBX: ffff888c0af94c00 RCX: ffffffff81e12500 RDX: 000000000000002e RSI: ffff888c0af94c00 RDI: ffff888c10b22600 RBP: ffffc9000c2bbd08 R08: 0000000000000009 R09: 0000000000000078 R10: ffffffff81e12440 R11: ffffffff81e1236c R12: ffff888bc8932600 R13: ffff888c0af94eb8 R14: ffff888c10b22600 R15: ffff888bc8932600 FS: 00007fa58ac55700(0000) GS:ffff888c10b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa58b523230 CR3: 0000000bf44ab003 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? intel_pstate_update_util_hwp+0x13/0x170 rt_mutex_setprio+0x1cc/0x4b0 task_blocks_on_rt_mutex+0x225/0x260 rt_spin_lock_slowlock_locked+0xab/0x2d0 rt_spin_lock_slowlock+0x50/0x80 hrtimer_grab_expiry_lock+0x20/0x30 hrtimer_cancel+0x13/0x30 do_nanosleep+0xa0/0x150 hrtimer_nanosleep+0xe1/0x230 ? __hrtimer_init_sleeper+0x60/0x60 __x64_sys_nanosleep+0x8d/0xa0 do_syscall_64+0x4a/0x100 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7fa58b52330d ... ---[ end trace 0000000000000002 ]— He also provided a simple reproducer creating the situation below: So the execution order of locking steps are the following (N1 and N2 are non-deadline tasks. D1 is a deadline task. M1 and M2 are mutexes that are enabled * with priority inheritance.) Time moves forward as this timeline goes down: N1 N2 D1 | | | | | | Lock(M1) | | | | | | Lock(M2) | | | | | | Lock(M2) | | | | Lock(M1) | | (!!bug triggered!) | Daniel reported a similar situation as well, by just letting ksoftirqd run with DEADLINE (and eventually block on a mutex). Problem is that boosted entities (Priority Inheritance) use static DEADLINE parameters of the top priority waiter. However, there might be cases where top waiter could be a non-DEADLINE entity that is currently boosted by a DEADLINE entity from a different lock chain (i.e., nested priority chains involving entities of non-DEADLINE classes). In this case, top waiter static DEADLINE parameters could be null (initialized to 0 at fork()) and replenish_dl_entity() would hit a BUG(). Fix this by keeping track of the original donor and using its parameters when a task is boosted. Reported-by: Glenn Elliott <glenn@aurora.tech> Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Daniel Bristot de Oliveira <bristot@redhat.com> Link: https://lkml.kernel.org/r/20201117061432.517340-1-juri.lelli@redhat.com |
||
|
Peter Zijlstra
|
ec618b84f6 |
sched: Fix rq->nr_iowait ordering
schedule() ttwu()
deactivate_task(); if (p->on_rq && ...) // false
atomic_dec(&task_rq(p)->nr_iowait);
if (prev->in_iowait)
atomic_inc(&rq->nr_iowait);
Allows nr_iowait to be decremented before it gets incremented,
resulting in more dodgy IO-wait numbers than usual.
Note that because we can now do ttwu_queue_wakelist() before
p->on_cpu==0, we lose the natural ordering and have to further delay
the decrement.
Fixes:
|
||
|
Quentin Perret
|
8e1ac4299a |
sched/fair: Fix overutilized update in enqueue_task_fair()
enqueue_task_fair() attempts to skip the overutilized update for new
tasks as their util_avg is not accurate yet. However, the flag we check
to do so is overwritten earlier on in the function, which makes the
condition pretty much a nop.
Fix this by saving the flag early on.
Fixes:
|
||
|
Linus Torvalds
|
d0a37fd57f |
A set of scheduler fixes:
- Address a load balancer regression by making the load balancer use the
same logic as the wakeup path to spread tasks in the LLC domain.
- Prefer the CPU on which a task run last over the local CPU in the fast
wakeup path for asymmetric CPU capacity systems to align with the
symmetric case. This ensures more locality and prevents massive
migration overhead on those asymetric systems
- Fix a memory corruption bug in the scheduler debug code caused by
handing a modified buffer pointer to kfree().
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Merge tag 'sched-urgent-2020-11-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
"A set of scheduler fixes:
- Address a load balancer regression by making the load balancer use
the same logic as the wakeup path to spread tasks in the LLC domain
- Prefer the CPU on which a task run last over the local CPU in the
fast wakeup path for asymmetric CPU capacity systems to align with
the symmetric case. This ensures more locality and prevents massive
migration overhead on those asymetric systems
- Fix a memory corruption bug in the scheduler debug code caused by
handing a modified buffer pointer to kfree()"
* tag 'sched-urgent-2020-11-15' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/debug: Fix memory corruption caused by multiple small reads of flags
sched/fair: Prefer prev cpu in asymmetric wakeup path
sched/fair: Ensure tasks spreading in LLC during LB
|
||
|
Colin Ian King
|
8d4d9c7b43 |
sched/debug: Fix memory corruption caused by multiple small reads of flags
Reading /proc/sys/kernel/sched_domain/cpu*/domain0/flags mutliple times
with small reads causes oopses with slub corruption issues because the kfree is
free'ing an offset from a previous allocation. Fix this by adding in a new
pointer 'buf' for the allocation and kfree and use the temporary pointer tmp
to handle memory copies of the buf offsets.
Fixes:
|
||
|
Vincent Guittot
|
b4c9c9f156 |
sched/fair: Prefer prev cpu in asymmetric wakeup path
During fast wakeup path, scheduler always check whether local or prev cpus are good candidates for the task before looking for other cpus in the domain. With commit |
||
|
Vincent Guittot
|
16b0a7a1a0 |
sched/fair: Ensure tasks spreading in LLC during LB
schbench shows latency increase for 95 percentile above since: commit |
||
|
Rafael J. Wysocki
|
9a2a9ebc0a |
cpufreq: Introduce governor flags
A new cpufreq governor flag will be added subsequently, so replace the bool dynamic_switching fleid in struct cpufreq_governor with a flags field and introduce CPUFREQ_GOV_DYNAMIC_SWITCHING to set for the "dynamic switching" governors instead of it. No intentional functional impact. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> |
||
|
Viresh Kumar
|
23a881852f |
cpufreq: schedutil: Don't skip freq update if need_freq_update is set
The cpufreq policy's frequency limits (min/max) can get changed at any point of time, while schedutil is trying to update the next frequency. Though the schedutil governor has necessary locking and support in place to make sure we don't miss any of those updates, there is a corner case where the governor will find that the CPU is already running at the desired frequency and so may skip an update. For example, consider that the CPU can run at 1 GHz, 1.2 GHz and 1.4 GHz and is running at 1 GHz currently. Schedutil tries to update the frequency to 1.2 GHz, during this time the policy limits get changed as policy->min = 1.4 GHz. As schedutil (and cpufreq core) does clamp the frequency at various instances, we will eventually set the frequency to 1.4 GHz, while we will save 1.2 GHz in sg_policy->next_freq. Now lets say the policy limits get changed back at this time with policy->min as 1 GHz. The next time schedutil is invoked by the scheduler, we will reevaluate the next frequency (because need_freq_update will get set due to limits change event) and lets say we want to set the frequency to 1.2 GHz again. At this point sugov_update_next_freq() will find the next_freq == current_freq and will abort the update, while the CPU actually runs at 1.4 GHz. Until now need_freq_update was used as a flag to indicate that the policy's frequency limits have changed, and that we should consider the new limits while reevaluating the next frequency. This patch fixes the above mentioned issue by extending the purpose of the need_freq_update flag. If this flag is set now, the schedutil governor will not try to abort a frequency change even if next_freq == current_freq. As similar behavior is required in the case of CPUFREQ_NEED_UPDATE_LIMITS flag as well, need_freq_update will never be set to false if that flag is set for the driver. We also don't need to consider the need_freq_update flag in sugov_update_single() anymore to handle the special case of busy CPU, as we won't abort a frequency update anymore. Reported-by: zhuguangqing <zhuguangqing@xiaomi.com> Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Rearrange code to avoid a branch ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
||
|
Rafael J. Wysocki
|
d1e7c2996e |
cpufreq: schedutil: Always call driver if CPUFREQ_NEED_UPDATE_LIMITS is set
Because sugov_update_next_freq() may skip a frequency update even if the need_freq_update flag has been set for the policy at hand, policy limits updates may not take effect as expected. For example, if the intel_pstate driver operates in the passive mode with HWP enabled, it needs to update the HWP min and max limits when the policy min and max limits change, respectively, but that may not happen if the target frequency does not change along with the limit at hand. In particular, if the policy min is changed first, causing the target frequency to be adjusted to it, and the policy max limit is changed later to the same value, the HWP max limit will not be updated to follow it as expected, because the target frequency is still equal to the policy min limit and it will not change until that limit is updated. To address this issue, modify get_next_freq() to let the driver callback run if the CPUFREQ_NEED_UPDATE_LIMITS cpufreq driver flag is set regardless of whether or not the new frequency to set is equal to the previous one. Fixes: |
||
|
Joe Perches
|
33def8498f |
treewide: Convert macro and uses of __section(foo) to __section("foo")
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.
Remove the quote operator # from compiler_attributes.h __section macro.
Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.
Conversion done using the script at:
https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl
Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
Linus Torvalds
|
87702a337f |
Two scheduler fixes:
- A trivial build fix for sched_feat() to compile correctly with
CONFIG_JUMP_LABEL=n
- Replace a zero lenght array with a flexible array.
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Merge tag 'sched-urgent-2020-10-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
"Two scheduler fixes:
- A trivial build fix for sched_feat() to compile correctly with
CONFIG_JUMP_LABEL=n
- Replace a zero lenght array with a flexible array"
* tag 'sched-urgent-2020-10-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/features: Fix !CONFIG_JUMP_LABEL case
sched: Replace zero-length array with flexible-array
|
||
|
Linus Torvalds
|
41f762a15a |
More power management updates for 5.10-rc1
- Move the AVS drivers to new platform-specific locations and get
rid of the drivers/power/avs directory (Ulf Hansson).
- Add on/off notifiers and idle state accounting support to the
generic power domains (genpd) framework (Ulf Hansson, Lina Iyer).
- Ulf will maintain the PM domain part of cpuidle-psci (Ulf Hansson).
- Make intel_idle disregard ACPI _CST if it cannot use the data
returned by that method (Mel Gorman).
- Modify intel_pstate to avoid leaving useless sysfs directory
structure behind if it cannot be registered (Chen Yu).
- Fix domain detection in the RAPL power capping driver and prevent
it from failing to enumerate the Psys RAPL domain (Zhang Rui).
- Allow acpi-cpufreq to use ACPI _PSD information with Family 19 and
later AMD chips (Wei Huang).
- Update the driver assumptions comment in intel_idle and fix a
kerneldoc comment in the runtime PM framework (Alexander Monakov,
Bean Huo).
- Avoid unnecessary resets of the cached frequency in the schedutil
cpufreq governor to reduce overhead (Wei Wang).
- Clean up the cpufreq core a bit (Viresh Kumar).
- Make assorted minor janitorial changes (Daniel Lezcano, Geert
Uytterhoeven, Hubert Jasudowicz, Tom Rix).
- Clean up and optimize the cpupower utility somewhat (Colin Ian
King, Martin Kaistra).
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Merge tag 'pm-5.10-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull more power management updates from Rafael Wysocki:
"First of all, the adaptive voltage scaling (AVS) drivers go to new
platform-specific locations as planned (this part was reported to have
merge conflicts against the new arm-soc updates in linux-next).
In addition to that, there are some fixes (intel_idle, intel_pstate,
RAPL, acpi_cpufreq), the addition of on/off notifiers and idle state
accounting support to the generic power domains (genpd) code and some
janitorial changes all over.
Specifics:
- Move the AVS drivers to new platform-specific locations and get rid
of the drivers/power/avs directory (Ulf Hansson).
- Add on/off notifiers and idle state accounting support to the
generic power domains (genpd) framework (Ulf Hansson, Lina Iyer).
- Ulf will maintain the PM domain part of cpuidle-psci (Ulf Hansson).
- Make intel_idle disregard ACPI _CST if it cannot use the data
returned by that method (Mel Gorman).
- Modify intel_pstate to avoid leaving useless sysfs directory
structure behind if it cannot be registered (Chen Yu).
- Fix domain detection in the RAPL power capping driver and prevent
it from failing to enumerate the Psys RAPL domain (Zhang Rui).
- Allow acpi-cpufreq to use ACPI _PSD information with Family 19 and
later AMD chips (Wei Huang).
- Update the driver assumptions comment in intel_idle and fix a
kerneldoc comment in the runtime PM framework (Alexander Monakov,
Bean Huo).
- Avoid unnecessary resets of the cached frequency in the schedutil
cpufreq governor to reduce overhead (Wei Wang).
- Clean up the cpufreq core a bit (Viresh Kumar).
- Make assorted minor janitorial changes (Daniel Lezcano, Geert
Uytterhoeven, Hubert Jasudowicz, Tom Rix).
- Clean up and optimize the cpupower utility somewhat (Colin Ian
King, Martin Kaistra)"
* tag 'pm-5.10-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (23 commits)
PM: sleep: remove unreachable break
PM: AVS: Drop the avs directory and the corresponding Kconfig
PM: AVS: qcom-cpr: Move the driver to the qcom specific drivers
PM: runtime: Fix typo in pm_runtime_set_active() helper comment
PM: domains: Fix build error for genpd notifiers
powercap: Fix typo in Kconfig "Plance" -> "Plane"
cpufreq: schedutil: restore cached freq when next_f is not changed
acpi-cpufreq: Honor _PSD table setting on new AMD CPUs
PM: AVS: smartreflex Move driver to soc specific drivers
PM: AVS: rockchip-io: Move the driver to the rockchip specific drivers
PM: domains: enable domain idle state accounting
PM: domains: Add curly braces to delimit comment + statement block
PM: domains: Add support for PM domain on/off notifiers for genpd
powercap/intel_rapl: enumerate Psys RAPL domain together with package RAPL domain
powercap/intel_rapl: Fix domain detection
intel_idle: Ignore _CST if control cannot be taken from the platform
cpuidle: Remove pointless stub
intel_idle: mention assumption that WBINVD is not needed
MAINTAINERS: Add section for cpuidle-psci PM domain
cpufreq: intel_pstate: Delete intel_pstate sysfs if failed to register the driver
...
|
||
|
Wei Wang
|
0070ea2962 |
cpufreq: schedutil: restore cached freq when next_f is not changed
We have the raw cached freq to reduce the chance in calling cpufreq driver where it could be costly in some arch/SoC. Currently, the raw cached freq is reset in sugov_update_single() when it avoids frequency reduction (which is not desirable sometimes), but it is better to restore the previous value of it in that case, because it may not change in the next cycle and it is not necessary to change the CPU frequency then. Adapted from https://android-review.googlesource.com/1352810/ Signed-off-by: Wei Wang <wvw@google.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> [ rjw: Subject edit and changelog rewrite ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
||
|
Jens Axboe
|
91989c7078 |
task_work: cleanup notification modes
A previous commit changed the notification mode from true/false to an
int, allowing notify-no, notify-yes, or signal-notify. This was
backwards compatible in the sense that any existing true/false user
would translate to either 0 (on notification sent) or 1, the latter
which mapped to TWA_RESUME. TWA_SIGNAL was assigned a value of 2.
Clean this up properly, and define a proper enum for the notification
mode. Now we have:
- TWA_NONE. This is 0, same as before the original change, meaning no
notification requested.
- TWA_RESUME. This is 1, same as before the original change, meaning
that we use TIF_NOTIFY_RESUME.
- TWA_SIGNAL. This uses TIF_SIGPENDING/JOBCTL_TASK_WORK for the
notification.
Clean up all the callers, switching their 0/1/false/true to using the
appropriate TWA_* mode for notifications.
Fixes:
|
||
|
Juri Lelli
|
a73f863af4 |
sched/features: Fix !CONFIG_JUMP_LABEL case
Commit: |
||
|
zhuguangqing
|
eba9f08293 |
sched: Replace zero-length array with flexible-array
In the following commit:
04f5c362ec6d: ("sched/fair: Replace zero-length array with flexible-array")
a zero-length array cpumask[0] has been replaced with cpumask[].
But there is still a cpumask[0] in 'struct sched_group_capacity'
which was missed.
The point of using [] instead of [0] is that with [] the compiler will
generate a build warning if it isn't the last member of a struct.
[ mingo: Rewrote the changelog. ]
Signed-off-by: zhuguangqing <zhuguangqing@xiaomi.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20201014140220.11384-1-zhuguangqing83@gmail.com
|
||
|
Linus Torvalds
|
0b8417c141 |
Power management updates for 5.10-rc1
- Rework cpufreq statistics collection to allow it to take place
when fast frequency switching is enabled in the governor (Viresh
Kumar).
- Make the cpufreq core set the frequency scale on behalf of the
driver and update several cpufreq drivers accordingly (Ionela
Voinescu, Valentin Schneider).
- Add new hardware support to the STI and qcom cpufreq drivers and
improve them (Alain Volmat, Manivannan Sadhasivam).
- Fix multiple assorted issues in cpufreq drivers (Jon Hunter,
Krzysztof Kozlowski, Matthias Kaehlcke, Pali Rohár, Stephan
Gerhold, Viresh Kumar).
- Fix several assorted issues in the operating performance points
(OPP) framework (Stephan Gerhold, Viresh Kumar).
- Allow devfreq drivers to fetch devfreq instances by DT enumeration
instead of using explicit phandles and modify the devfreq core
code to support driver-specific devfreq DT bindings (Leonard
Crestez, Chanwoo Choi).
- Improve initial hardware resetting in the tegra30 devfreq driver
and clean up the tegra cpuidle driver (Dmitry Osipenko).
- Update the cpuidle core to collect state entry rejection
statistics and expose them via sysfs (Lina Iyer).
- Improve the ACPI _CST code handling diagnostics (Chen Yu).
- Update the PSCI cpuidle driver to allow the PM domain
initialization to occur in the OSI mode as well as in the PC
mode (Ulf Hansson).
- Rework the generic power domains (genpd) core code to allow
domain power off transition to be aborted in the absence of the
"power off" domain callback (Ulf Hansson).
- Fix two suspend-to-idle issues in the ACPI EC driver (Rafael
Wysocki).
- Fix the handling of timer_expires in the PM-runtime framework on
32-bit systems and the handling of device links in it (Grygorii
Strashko, Xiang Chen).
- Add IO requests batching support to the hibernate image saving and
reading code and drop a bogus get_gendisk() from there (Xiaoyi
Chen, Christoph Hellwig).
- Allow PCIe ports to be put into the D3cold power state if they
are power-manageable via ACPI (Lukas Wunner).
- Add missing header file include to a power capping driver (Pujin
Shi).
- Clean up the qcom-cpr AVS driver a bit (Liu Shixin).
- Kevin Hilman steps down as designated reviwer of adaptive voltage
scaling (AVS) driverrs (Kevin Hilman).
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Merge tag 'pm-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"These rework the collection of cpufreq statistics to allow it to take
place if fast frequency switching is enabled in the governor, rework
the frequency invariance handling in the cpufreq core and drivers, add
new hardware support to a couple of cpufreq drivers, fix a number of
assorted issues and clean up the code all over.
Specifics:
- Rework cpufreq statistics collection to allow it to take place when
fast frequency switching is enabled in the governor (Viresh Kumar).
- Make the cpufreq core set the frequency scale on behalf of the
driver and update several cpufreq drivers accordingly (Ionela
Voinescu, Valentin Schneider).
- Add new hardware support to the STI and qcom cpufreq drivers and
improve them (Alain Volmat, Manivannan Sadhasivam).
- Fix multiple assorted issues in cpufreq drivers (Jon Hunter,
Krzysztof Kozlowski, Matthias Kaehlcke, Pali Rohár, Stephan
Gerhold, Viresh Kumar).
- Fix several assorted issues in the operating performance points
(OPP) framework (Stephan Gerhold, Viresh Kumar).
- Allow devfreq drivers to fetch devfreq instances by DT enumeration
instead of using explicit phandles and modify the devfreq core code
to support driver-specific devfreq DT bindings (Leonard Crestez,
Chanwoo Choi).
- Improve initial hardware resetting in the tegra30 devfreq driver
and clean up the tegra cpuidle driver (Dmitry Osipenko).
- Update the cpuidle core to collect state entry rejection statistics
and expose them via sysfs (Lina Iyer).
- Improve the ACPI _CST code handling diagnostics (Chen Yu).
- Update the PSCI cpuidle driver to allow the PM domain
initialization to occur in the OSI mode as well as in the PC mode
(Ulf Hansson).
- Rework the generic power domains (genpd) core code to allow domain
power off transition to be aborted in the absence of the "power
off" domain callback (Ulf Hansson).
- Fix two suspend-to-idle issues in the ACPI EC driver (Rafael
Wysocki).
- Fix the handling of timer_expires in the PM-runtime framework on
32-bit systems and the handling of device links in it (Grygorii
Strashko, Xiang Chen).
- Add IO requests batching support to the hibernate image saving and
reading code and drop a bogus get_gendisk() from there (Xiaoyi
Chen, Christoph Hellwig).
- Allow PCIe ports to be put into the D3cold power state if they are
power-manageable via ACPI (Lukas Wunner).
- Add missing header file include to a power capping driver (Pujin
Shi).
- Clean up the qcom-cpr AVS driver a bit (Liu Shixin).
- Kevin Hilman steps down as designated reviwer of adaptive voltage
scaling (AVS) drivers (Kevin Hilman)"
* tag 'pm-5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (65 commits)
cpufreq: stats: Fix string format specifier mismatch
arm: disable frequency invariance for CONFIG_BL_SWITCHER
cpufreq,arm,arm64: restructure definitions of arch_set_freq_scale()
cpufreq: stats: Add memory barrier to store_reset()
cpufreq: schedutil: Simplify sugov_fast_switch()
ACPI: EC: PM: Drop ec_no_wakeup check from acpi_ec_dispatch_gpe()
ACPI: EC: PM: Flush EC work unconditionally after wakeup
PCI/ACPI: Whitelist hotplug ports for D3 if power managed by ACPI
PM: hibernate: remove the bogus call to get_gendisk() in software_resume()
cpufreq: Move traces and update to policy->cur to cpufreq core
cpufreq: stats: Enable stats for fast-switch as well
cpufreq: stats: Mark few conditionals with unlikely()
cpufreq: stats: Remove locking
cpufreq: stats: Defer stats update to cpufreq_stats_record_transition()
PM: domains: Allow to abort power off when no ->power_off() callback
PM: domains: Rename power state enums for genpd
PM / devfreq: tegra30: Improve initial hardware resetting
PM / devfreq: event: Change prototype of devfreq_event_get_edev_by_phandle function
PM / devfreq: Change prototype of devfreq_get_devfreq_by_phandle function
PM / devfreq: Add devfreq_get_devfreq_by_node function
...
|
||
|
Linus Torvalds
|
edaa5ddf38 |
Scheduler changes for v5.10:
- Reorganize & clean up the SD* flags definitions and add a bunch
of sanity checks. These new checks caught quite a few bugs or at
least inconsistencies, resulting in another set of patches.
- Rseq updates, add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
- Add a new tracepoint to improve CPU capacity tracking
- Improve overloaded SMP system load-balancing behavior
- Tweak SMT balancing
- Energy-aware scheduling updates
- NUMA balancing improvements
- Deadline scheduler fixes and improvements
- CPU isolation fixes
- Misc cleanups, simplifications and smaller optimizations.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- reorganize & clean up the SD* flags definitions and add a bunch of
sanity checks. These new checks caught quite a few bugs or at least
inconsistencies, resulting in another set of patches.
- rseq updates, add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
- add a new tracepoint to improve CPU capacity tracking
- improve overloaded SMP system load-balancing behavior
- tweak SMT balancing
- energy-aware scheduling updates
- NUMA balancing improvements
- deadline scheduler fixes and improvements
- CPU isolation fixes
- misc cleanups, simplifications and smaller optimizations
* tag 'sched-core-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
sched/deadline: Unthrottle PI boosted threads while enqueuing
sched/debug: Add new tracepoint to track cpu_capacity
sched/fair: Tweak pick_next_entity()
rseq/selftests: Test MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
rseq/selftests,x86_64: Add rseq_offset_deref_addv()
rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
sched/fair: Use dst group while checking imbalance for NUMA balancer
sched/fair: Reduce busy load balance interval
sched/fair: Minimize concurrent LBs between domain level
sched/fair: Reduce minimal imbalance threshold
sched/fair: Relax constraint on task's load during load balance
sched/fair: Remove the force parameter of update_tg_load_avg()
sched/fair: Fix wrong cpu selecting from isolated domain
sched: Remove unused inline function uclamp_bucket_base_value()
sched/rt: Disable RT_RUNTIME_SHARE by default
sched/deadline: Fix stale throttling on de-/boosted tasks
sched/numa: Use runnable_avg to classify node
sched/topology: Move sd_flag_debug out of #ifdef CONFIG_SYSCTL
MAINTAINERS: Add myself as SCHED_DEADLINE reviewer
sched/topology: Move SD_DEGENERATE_GROUPS_MASK out of linux/sched/topology.h
...
|
||
|
Rafael J. Wysocki
|
86836bac55 |
cpufreq: schedutil: Simplify sugov_fast_switch()
Drop a redundant local variable definition from sugov_fast_switch() and rearrange the code in there to avoid the redundant logical negation. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> |
||
|
Viresh Kumar
|
08d8c65e84 |
cpufreq: Move traces and update to policy->cur to cpufreq core
The cpufreq core handles the updates to policy->cur and recording of cpufreq trace events for all the governors except schedutil's fast switch case. Move that as well to cpufreq core for consistency and readability. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
||
|
Daniel Bristot de Oliveira
|
feff2e65ef |
sched/deadline: Unthrottle PI boosted threads while enqueuing
stress-ng has a test (stress-ng --cyclic) that creates a set of threads
under SCHED_DEADLINE with the following parameters:
dl_runtime = 10000 (10 us)
dl_deadline = 100000 (100 us)
dl_period = 100000 (100 us)
These parameters are very aggressive. When using a system without HRTICK
set, these threads can easily execute longer than the dl_runtime because
the throttling happens with 1/HZ resolution.
During the main part of the test, the system works just fine because
the workload does not try to run over the 10 us. The problem happens at
the end of the test, on the exit() path. During exit(), the threads need
to do some cleanups that require real-time mutex locks, mainly those
related to memory management, resulting in this scenario:
Note: locks are rt_mutexes...
------------------------------------------------------------------------
TASK A: TASK B: TASK C:
activation
activation
activation
lock(a): OK! lock(b): OK!
<overrun runtime>
lock(a)
-> block (task A owns it)
-> self notice/set throttled
+--< -> arm replenished timer
| switch-out
| lock(b)
| -> <C prio > B prio>
| -> boost TASK B
| unlock(a) switch-out
| -> handle lock a to B
| -> wakeup(B)
| -> B is throttled:
| -> do not enqueue
| switch-out
|
|
+---------------------> replenishment timer
-> TASK B is boosted:
-> do not enqueue
------------------------------------------------------------------------
BOOM: TASK B is runnable but !enqueued, holding TASK C: the system
crashes with hung task C.
This problem is avoided by removing the throttle state from the boosted
thread while boosting it (by TASK A in the example above), allowing it to
be queued and run boosted.
The next replenishment will take care of the runtime overrun, pushing
the deadline further away. See the "while (dl_se->runtime <= 0)" on
replenish_dl_entity() for more information.
Reported-by: Mark Simmons <msimmons@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: Mark Simmons <msimmons@redhat.com>
Link: https://lkml.kernel.org/r/5076e003450835ec74e6fa5917d02c4fa41687e6.1600170294.git.bristot@redhat.com
|
||
|
Vincent Donnefort
|
51cf18c90c |
sched/debug: Add new tracepoint to track cpu_capacity
rq->cpu_capacity is a key element in several scheduler parts, such as EAS task placement and load balancing. Tracking this value enables testing and/or debugging by a toolkit. Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/1598605249-72651-1-git-send-email-vincent.donnefort@arm.com |
||
|
Peter Oskolkov
|
9abb897345 |
sched/fair: Tweak pick_next_entity()
Currently, pick_next_entity(...) has the following structure
(simplified):
[...]
if (last_buddy_ok())
result = last_buddy;
if (next_buddy_ok())
result = next_buddy;
[...]
The intended behavior is to prefer next buddy over last buddy;
the current code somewhat obfuscates this, and also wastes
cycles checking the last buddy when eventually the next buddy is
picked up.
So this patch refactors two 'ifs' above into
[...]
if (next_buddy_ok())
result = next_buddy;
else if (last_buddy_ok())
result = last_buddy;
[...]
Signed-off-by: Peter Oskolkov <posk@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guitttot@linaro.org>
Link: https://lkml.kernel.org/r/20200930173532.1069092-1-posk@google.com
|
||
|
Peter Oskolkov
|
2a36ab717e |
rseq/membarrier: Add MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ
This patchset is based on Google-internal RSEQ work done by Paul Turner and Andrew Hunter. When working with per-CPU RSEQ-based memory allocations, it is sometimes important to make sure that a global memory location is no longer accessed from RSEQ critical sections. For example, there can be two per-CPU lists, one is "active" and accessed per-CPU, while another one is inactive and worked on asynchronously "off CPU" (e.g. garbage collection is performed). Then at some point the two lists are swapped, and a fast RCU-like mechanism is required to make sure that the previously active list is no longer accessed. This patch introduces such a mechanism: in short, membarrier() syscall issues an IPI to a CPU, restarting a potentially active RSEQ critical section on the CPU. Signed-off-by: Peter Oskolkov <posk@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lkml.kernel.org/r/20200923233618.2572849-1-posk@google.com |
||
|
Barry Song
|
233e7aca4c |
sched/fair: Use dst group while checking imbalance for NUMA balancer
Barry Song noted the following
Something is wrong. In find_busiest_group(), we are checking if
src has higher load, however, in task_numa_find_cpu(), we are
checking if dst will have higher load after balancing. It seems
it is not sensible to check src.
It maybe cause wrong imbalance value, for example,
if dst_running = env->dst_stats.nr_running + 1 results in 3 or
above, and src_running = env->src_stats.nr_running - 1 results
in 1;
The current code is thinking imbalance as 0 since src_running is
smaller than 2. This is inconsistent with load balancer.
Basically, in find_busiest_group(), the NUMA imbalance is ignored if moving
a task "from an almost idle domain" to a "domain with spare capacity". This
patch forbids movement "from a misplaced domain" to "an almost idle domain"
as that is closer to what the CPU load balancer expects.
This patch is not a universal win. The old behaviour was intended to allow
a task from an almost idle NUMA node to migrate to its preferred node if
the destination had capacity but there are corner cases. For example,
a NAS compute load could be parallelised to use 1/3rd of available CPUs
but not all those potential tasks are active at all times allowing this
logic to trigger. An obvious example is specjbb 2005 running various
numbers of warehouses on a 2 socket box with 80 cpus.
specjbb
5.9.0-rc4 5.9.0-rc4
vanilla dstbalance-v1r1
Hmean tput-1 46425.00 ( 0.00%) 43394.00 * -6.53%*
Hmean tput-2 98416.00 ( 0.00%) 96031.00 * -2.42%*
Hmean tput-3 150184.00 ( 0.00%) 148783.00 * -0.93%*
Hmean tput-4 200683.00 ( 0.00%) 197906.00 * -1.38%*
Hmean tput-5 236305.00 ( 0.00%) 245549.00 * 3.91%*
Hmean tput-6 281559.00 ( 0.00%) 285692.00 * 1.47%*
Hmean tput-7 338558.00 ( 0.00%) 334467.00 * -1.21%*
Hmean tput-8 340745.00 ( 0.00%) 372501.00 * 9.32%*
Hmean tput-9 424343.00 ( 0.00%) 413006.00 * -2.67%*
Hmean tput-10 421854.00 ( 0.00%) 434261.00 * 2.94%*
Hmean tput-11 493256.00 ( 0.00%) 485330.00 * -1.61%*
Hmean tput-12 549573.00 ( 0.00%) 529959.00 * -3.57%*
Hmean tput-13 593183.00 ( 0.00%) 555010.00 * -6.44%*
Hmean tput-14 588252.00 ( 0.00%) 599166.00 * 1.86%*
Hmean tput-15 623065.00 ( 0.00%) 642713.00 * 3.15%*
Hmean tput-16 703924.00 ( 0.00%) 660758.00 * -6.13%*
Hmean tput-17 666023.00 ( 0.00%) 697675.00 * 4.75%*
Hmean tput-18 761502.00 ( 0.00%) 758360.00 * -0.41%*
Hmean tput-19 796088.00 ( 0.00%) 798368.00 * 0.29%*
Hmean tput-20 733564.00 ( 0.00%) 823086.00 * 12.20%*
Hmean tput-21 840980.00 ( 0.00%) 856711.00 * 1.87%*
Hmean tput-22 804285.00 ( 0.00%) 872238.00 * 8.45%*
Hmean tput-23 795208.00 ( 0.00%) 889374.00 * 11.84%*
Hmean tput-24 848619.00 ( 0.00%) 966783.00 * 13.92%*
Hmean tput-25 750848.00 ( 0.00%) 903790.00 * 20.37%*
Hmean tput-26 780523.00 ( 0.00%) 962254.00 * 23.28%*
Hmean tput-27 1042245.00 ( 0.00%) 991544.00 * -4.86%*
Hmean tput-28 1090580.00 ( 0.00%) 1035926.00 * -5.01%*
Hmean tput-29 999483.00 ( 0.00%) 1082948.00 * 8.35%*
Hmean tput-30 1098663.00 ( 0.00%) 1113427.00 * 1.34%*
Hmean tput-31 1125671.00 ( 0.00%) 1134175.00 * 0.76%*
Hmean tput-32 968167.00 ( 0.00%) 1250286.00 * 29.14%*
Hmean tput-33 1077676.00 ( 0.00%) 1060893.00 * -1.56%*
Hmean tput-34 1090538.00 ( 0.00%) 1090933.00 * 0.04%*
Hmean tput-35 967058.00 ( 0.00%) 1107421.00 * 14.51%*
Hmean tput-36 1051745.00 ( 0.00%) 1210663.00 * 15.11%*
Hmean tput-37 1019465.00 ( 0.00%) 1351446.00 * 32.56%*
Hmean tput-38 1083102.00 ( 0.00%) 1064541.00 * -1.71%*
Hmean tput-39 1232990.00 ( 0.00%) 1303623.00 * 5.73%*
Hmean tput-40 1175542.00 ( 0.00%) 1340943.00 * 14.07%*
Hmean tput-41 1127826.00 ( 0.00%) 1339492.00 * 18.77%*
Hmean tput-42 1198313.00 ( 0.00%) 1411023.00 * 17.75%*
Hmean tput-43 1163733.00 ( 0.00%) 1228253.00 * 5.54%*
Hmean tput-44 1305562.00 ( 0.00%) 1357886.00 * 4.01%*
Hmean tput-45 1326752.00 ( 0.00%) 1406061.00 * 5.98%*
Hmean tput-46 1339424.00 ( 0.00%) 1418451.00 * 5.90%*
Hmean tput-47 1415057.00 ( 0.00%) 1381570.00 * -2.37%*
Hmean tput-48 1392003.00 ( 0.00%) 1421167.00 * 2.10%*
Hmean tput-49 1408374.00 ( 0.00%) 1418659.00 * 0.73%*
Hmean tput-50 1359822.00 ( 0.00%) 1391070.00 * 2.30%*
Hmean tput-51 1414246.00 ( 0.00%) 1392679.00 * -1.52%*
Hmean tput-52 1432352.00 ( 0.00%) 1354020.00 * -5.47%*
Hmean tput-53 1387563.00 ( 0.00%) 1409563.00 * 1.59%*
Hmean tput-54 1406420.00 ( 0.00%) 1388711.00 * -1.26%*
Hmean tput-55 1438804.00 ( 0.00%) 1387472.00 * -3.57%*
Hmean tput-56 1399465.00 ( 0.00%) 1400296.00 * 0.06%*
Hmean tput-57 1428132.00 ( 0.00%) 1396399.00 * -2.22%*
Hmean tput-58 1432385.00 ( 0.00%) 1386253.00 * -3.22%*
Hmean tput-59 1421612.00 ( 0.00%) 1371416.00 * -3.53%*
Hmean tput-60 1429423.00 ( 0.00%) 1389412.00 * -2.80%*
Hmean tput-61 1396230.00 ( 0.00%) 1351122.00 * -3.23%*
Hmean tput-62 1418396.00 ( 0.00%) 1383098.00 * -2.49%*
Hmean tput-63 1409918.00 ( 0.00%) 1374662.00 * -2.50%*
Hmean tput-64 1410236.00 ( 0.00%) 1376216.00 * -2.41%*
Hmean tput-65 1396405.00 ( 0.00%) 1364418.00 * -2.29%*
Hmean tput-66 1395975.00 ( 0.00%) 1357326.00 * -2.77%*
Hmean tput-67 1392986.00 ( 0.00%) 1349642.00 * -3.11%*
Hmean tput-68 1386541.00 ( 0.00%) 1343261.00 * -3.12%*
Hmean tput-69 1374407.00 ( 0.00%) 1342588.00 * -2.32%*
Hmean tput-70 1377513.00 ( 0.00%) 1334654.00 * -3.11%*
Hmean tput-71 1369319.00 ( 0.00%) 1334952.00 * -2.51%*
Hmean tput-72 1354635.00 ( 0.00%) 1329005.00 * -1.89%*
Hmean tput-73 1350933.00 ( 0.00%) 1318942.00 * -2.37%*
Hmean tput-74 1351714.00 ( 0.00%) 1316347.00 * -2.62%*
Hmean tput-75 1352198.00 ( 0.00%) 1309974.00 * -3.12%*
Hmean tput-76 1349490.00 ( 0.00%) 1286064.00 * -4.70%*
Hmean tput-77 1336131.00 ( 0.00%) 1303684.00 * -2.43%*
Hmean tput-78 1308896.00 ( 0.00%) 1271024.00 * -2.89%*
Hmean tput-79 1326703.00 ( 0.00%) 1290862.00 * -2.70%*
Hmean tput-80 1336199.00 ( 0.00%) 1291629.00 * -3.34%*
The performance at the mid-point is better but not universally better. The
patch is a mixed bag depending on the workload, machine and overall
levels of utilisation. Sometimes it's better (sometimes much better),
other times it is worse (sometimes much worse). Given that there isn't a
universally good decision in this section and more people seem to prefer
the patch then it may be best to keep the LB decisions consistent and
revisit imbalance handling when the load balancer code changes settle down.
Jirka Hladky added the following observation.
Our results are mostly in line with what you see. We observe
big gains (20-50%) when the system is loaded to 1/3 of the
maximum capacity and mixed results at the full load - some
workloads benefit from the patch at the full load, others not,
but performance changes at the full load are mostly within the
noise of results (+/-5%). Overall, we think this patch is helpful.
[mgorman@techsingularity.net: Rewrote changelog]
Fixes:
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Vincent Guittot
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6e7499135d |
sched/fair: Reduce busy load balance interval
The busy_factor, which increases load balance interval when a cpu is busy, is set to 32 by default. This value generates some huge LB interval on large system like the THX2 made of 2 node x 28 cores x 4 threads. For such system, the interval increases from 112ms to 3584ms at MC level. And from 228ms to 7168ms at NUMA level. Even on smaller system, a lower busy factor has shown improvement on the fair distribution of the running time so let reduce it for all. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/20200921072424.14813-5-vincent.guittot@linaro.org |
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Vincent Guittot
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e4d32e4d54 |
sched/fair: Minimize concurrent LBs between domain level
sched domains tend to trigger simultaneously the load balance loop but the larger domains often need more time to collect statistics. This slowness makes the larger domain trying to detach tasks from a rq whereas tasks already migrated somewhere else at a sub-domain level. This is not a real problem for idle LB because the period of smaller domains will increase with its CPUs being busy and this will let time for higher ones to pulled tasks. But this becomes a problem when all CPUs are already busy because all domains stay synced when they trigger their LB. A simple way to minimize simultaneous LB of all domains is to decrement the the busy interval by 1 jiffies. Because of the busy_factor, the interval of larger domain will not be a multiple of smaller ones anymore. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Link: https://lkml.kernel.org/r/20200921072424.14813-4-vincent.guittot@linaro.org |
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Vincent Guittot
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2208cdaa56 |
sched/fair: Reduce minimal imbalance threshold
The 25% default imbalance threshold for DIE and NUMA domain is large enough to generate significant unfairness between threads. A typical example is the case of 11 threads running on 2x4 CPUs. The imbalance of 20% between the 2 groups of 4 cores is just low enough to not trigger the load balance between the 2 groups. We will have always the same 6 threads on one group of 4 CPUs and the other 5 threads on the other group of CPUS. With a fair time sharing in each group, we ends up with +20% running time for the group of 5 threads. Consider decreasing the imbalance threshold for overloaded case where we use the load to balance task and to ensure fair time sharing. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Phil Auld <pauld@redhat.com> Acked-by: Hillf Danton <hdanton@sina.com> Link: https://lkml.kernel.org/r/20200921072424.14813-3-vincent.guittot@linaro.org |