No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Jie Zhan 73cee9b56a cpufreq: governor: Fix negative 'idle_time' handling in dbs_update()
[ Upstream commit 3698dd6b139dc37b35a9ad83d9330c1f99666c02 ]

We observed an issue that the CPU frequency can't raise up with a 100% CPU
load when NOHZ is off and the 'conservative' governor is selected.

'idle_time' can be negative if it's obtained from get_cpu_idle_time_jiffy()
when NOHZ is off.  This was found and explained in commit 9485e4ca0b
("cpufreq: governor: Fix handling of special cases in dbs_update()").

However, commit 7592019634 ("cpufreq: governors: Fix long idle detection
logic in load calculation") introduced a comparison between 'idle_time' and
'samling_rate' to detect a long idle interval.  While 'idle_time' is
converted to int before comparison, it's actually promoted to unsigned
again when compared with an unsigned 'sampling_rate'.  Hence, this leads to
wrong idle interval detection when it's in fact 100% busy and sets
policy_dbs->idle_periods to a very large value.  'conservative' adjusts the
frequency to minimum because of the large 'idle_periods', such that the
frequency can't raise up.  'Ondemand' doesn't use policy_dbs->idle_periods
so it fortunately avoids the issue.

Correct negative 'idle_time' to 0 before any use of it in dbs_update().

Fixes: 7592019634 ("cpufreq: governors: Fix long idle detection logic in load calculation")
Signed-off-by: Jie Zhan <zhanjie9@hisilicon.com>
Reviewed-by: Chen Yu <yu.c.chen@intel.com>
Link: https://patch.msgid.link/20250213035510.2402076-1-zhanjie9@hisilicon.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-04-10 14:29:39 +02:00
arch x86/mm/pat: cpa-test: fix length for CPA_ARRAY test 2025-04-10 14:29:39 +02:00
block block: fix 'kmem_cache of name 'bio-108' already exists' 2025-04-10 14:29:37 +02:00
certs
crypto crypto: testmgr - some more fixes to RSA test vectors 2025-03-13 12:43:21 +01:00
Documentation sched/isolation: Prevent boot crash when the boot CPU is nohz_full 2025-04-10 14:29:35 +02:00
drivers cpufreq: governor: Fix negative 'idle_time' handling in dbs_update() 2025-04-10 14:29:39 +02:00
fs fuse: don't truncate cached, mutated symlink 2025-04-10 14:29:36 +02:00
include fuse: don't truncate cached, mutated symlink 2025-04-10 14:29:36 +02:00
init initramfs: avoid filename buffer overrun 2024-12-14 19:44:21 +01:00
ipc ipc: replace costly bailout check in sysvipc_find_ipc() 2024-09-04 13:15:02 +02:00
kernel hrtimers: Mark is_migration_base() with __always_inline 2025-04-10 14:29:36 +02:00
lib lib: string_helpers: silence snprintf() output truncation warning 2024-12-14 19:44:39 +01:00
LICENSES
mm mm/page_alloc: fix uninitialized variable 2025-03-13 12:43:28 +01:00
net netfilter: socket: Lookup orig tuple for IPv6 SNAT 2025-04-10 14:29:39 +02:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts kbuild: Move -Wenum-enum-conversion to W=2 2025-03-13 12:43:09 +01:00
security ima: Fix use-after-free on a dentry's dname.name 2025-03-13 12:43:19 +01:00
sound ALSA: usb-audio: Add quirk for Plantronics headsets to fix control names 2025-04-10 14:29:38 +02:00
tools perf bench: Fix undefined behavior in cmpworker() 2025-03-13 12:43:08 +01:00
usr
virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Remove *.orig pattern from .gitignore 2024-11-08 16:20:33 +01:00
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.291 2025-03-13 12:43:33 +01:00
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.