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Xuewen Yan 3e1493f463 sched/uclamp: Ignore max aggregation if rq is idle
When a task wakes up on an idle rq, uclamp_rq_util_with() would max
aggregate with rq value. But since there is no task enqueued yet, the
values are stale based on the last task that was running. When the new
task actually wakes up and enqueued, then the rq uclamp values should
reflect that of the newly woken up task effective uclamp values.

This is a problem particularly for uclamp_max because it default to
1024. If a task p with uclamp_max = 512 wakes up, then max aggregation
would ignore the capping that should apply when this task is enqueued,
which is wrong.

Fix that by ignoring max aggregation if the rq is idle since in that
case the effective uclamp value of the rq will be the ones of the task
that will wake up.

Fixes: 9d20ad7dfc ("sched/uclamp: Add uclamp_util_with()")
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
[qias: Changelog]
Reviewed-by: Qais Yousef <qais.yousef@arm.com>
Link: https://lore.kernel.org/r/20210630141204.8197-1-xuewen.yan94@gmail.com
2021-07-02 15:58:24 +02:00
Documentation sched/doc: Update the CPU capacity asymmetry bits 2021-06-24 09:07:51 +02:00
LICENSES LICENSES: Add the CC-BY-4.0 license 2020-12-08 10:33:27 -07:00
arch sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
block sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
certs Kbuild updates for v5.13 (2nd) 2021-05-08 10:00:11 -07:00
crypto async_xor: check src_offs is not NULL before updating it 2021-06-10 19:40:14 -07:00
drivers sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
fs sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
include sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag 2021-06-24 09:07:50 +02:00
init sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
ipc ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry 2021-05-22 15:09:07 -10:00
kernel sched/uclamp: Ignore max aggregation if rq is idle 2021-07-02 15:58:24 +02:00
lib sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
mm sched: Introduce task_is_running() 2021-06-18 11:43:07 +02:00
net sched: Change task_struct::state 2021-06-18 11:43:09 +02:00
samples VFIO fixes for v5.13-rc5 2021-06-03 11:52:24 -07:00
scripts kbuild: Quote OBJCOPY var to avoid a pahole call break the build 2021-05-27 11:32:56 -07:00
security trusted-keys: match tpm_get_ops on all return paths 2021-05-12 22:36:37 +03:00
sound sound fixes for 5.13-rc6 2021-06-11 10:47:10 -07:00
tools Merge branch 'sched/urgent' into sched/core, to resolve conflicts 2021-06-18 11:31:25 +02:00
usr .gitignore: prefix local generated files with a slash 2021-05-02 00:43:35 +09:00
virt sched,perf,kvm: Fix preemption condition 2021-06-18 11:43:07 +02:00
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.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
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CREDITS MAINTAINERS: move Murali Karicheri to credits 2021-04-29 15:47:30 -07:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS USB fixes for 5.13-rc6 2021-06-12 12:34:49 -07:00
Makefile Linux 5.13-rc6 2021-06-13 14:43:10 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.