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Filename Latest commit message Latest commit date
Rafael J. Wysocki 18feee7b1c cpuidle: teo: Fix "early hits" handling for disabled idle states
commit 159e48560f51d9c2aa02d762a18cd24f7868ab27 upstream.

The TEO governor uses idle duration "bins" defined in accordance with
the CPU idle states table provided by the driver, so that each "bin"
covers the idle duration range between the target residency of the
idle state corresponding to it and the target residency of the closest
deeper idle state.  The governor collects statistics for each bin
regardless of whether or not the idle state corresponding to it is
currently enabled.

In particular, the "early hits" metric measures the likelihood of a
situation in which the idle duration measured after wakeup falls into
to given bin, but the time till the next timer (sleep length) falls
into a bin corresponding to one of the deeper idle states.  It is
used when the "hits" and "misses" metrics indicate that the state
"matching" the sleep length should not be selected, so that the state
with the maximum "early hits" value is selected instead of it.

If the idle state corresponding to the given bin is disabled, it
cannot be selected and if it turns out to be the one that should be
selected, a shallower idle state needs to be used instead of it.
Nevertheless, the metrics collected for the bin corresponding to it
are still valid and need to be taken into account as though that
state had not been disabled.

As far as the "early hits" metric is concerned, teo_select() tries to
take disabled states into account, but the state index corresponding
to the maximum "early hits" value computed by it may be incorrect.
Namely, it always uses the index of the previous maximum "early hits"
state then, but there may be enabled idle states closer to the
disabled one in question.  In particular, if the current candidate
state (whose index is the idx value) is closer to the disabled one
and the "early hits" value of the disabled state is greater than the
current maximum, the index of the current candidate state (idx)
should replace the "maximum early hits state" index.

Modify the code to handle that case correctly.

Fixes: b26bf6ab71 ("cpuidle: New timer events oriented governor for tickless systems")
Reported-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: 5.1+ <stable@vger.kernel.org> # 5.1+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17 19:56:22 +01:00
arch s390/mm: properly clear _PAGE_NOEXEC bit when it is not supported 2019-12-17 19:56:16 +01:00
block blk-mq: avoid sysfs buffer overflow with too many CPU cores 2019-12-17 19:56:14 +01:00
certs
crypto crypto: user - fix memory leak in crypto_reportstat 2019-12-13 08:43:11 +01:00
Documentation USB: documentation: flags on usb-storage versus UAS 2019-12-17 19:55:32 +01:00
drivers cpuidle: teo: Fix "early hits" handling for disabled idle states 2019-12-17 19:56:22 +01:00
fs ovl: relax WARN_ON() on rename to self 2019-12-17 19:56:11 +01:00
include media: cec.h: CEC_OP_REC_FLAG_ values were swapped 2019-12-17 19:56:20 +01:00
init Merge branch 'next-lockdown' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-09-28 08:14:15 -07:00
ipc ipc/sem.c: convert to use built-in RCU list checking 2019-09-25 17:51:41 -07:00
kernel cgroup: pids: use atomic64_t for pids->limit 2019-12-17 19:56:15 +01:00
lib lib: raid6: fix awk build warnings 2019-12-17 19:56:09 +01:00
LICENSES
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-11-22 09:11:18 -08:00
net rfkill: allocate static minor 2019-12-13 08:43:18 +01:00
samples samples/bpf: fix build by setting HAVE_ATTR_TEST to zero 2019-10-31 21:39:15 +01:00
scripts arm64 fix for -rc8 / final 2019-11-15 09:14:23 -08:00
security efi/efi_test: Lock down /dev/efi_test and require CAP_SYS_ADMIN 2019-10-31 09:40:21 +01:00
sound ASoC: fsl_audmix: Add spin lock to protect tdms 2019-12-17 19:56:14 +01:00
tools kselftest: Fix NULL INSTALL_PATH for TARGETS runlist 2019-12-13 08:43:31 +01:00
usr kbuild: update compile-test header list for v5.4-rc2 2019-10-05 15:29:49 +09:00
virt KVM: arm/arm64: vgic: Don't rely on the wrong pending table 2019-12-13 08:43:00 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore Modules updates for v5.4 2019-09-22 10:34:46 -07:00
.mailmap ARM: SoC fixes 2019-11-10 13:41:59 -08:00
COPYING
CREDITS MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer 2019-10-10 08:12:51 -07:00
Kbuild
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-11-22 14:28:14 -08:00
Makefile Linux 5.4.3 2019-12-13 08:43:32 +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.