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Filename Latest commit message Latest commit date
Mete Durlu 48cef94b69 s390/vtime: fix average steal time calculation
[ Upstream commit 367c50f78451d3bd7ad70bc5c89f9ba6dec46ca9 ]

Current average steal timer calculation produces volatile and inflated
values. The only user of this value is KVM so far and it uses that to
decide whether or not to yield the vCPU which is seeing steal time.
KVM compares average steal timer to a threshold and if the threshold
is past then it does not allow CPU polling and yields it to host, else
it keeps the CPU by polling.
Since KVM's steal time threshold is very low by default (%10) it most
likely is not effected much by the bloated average steal timer values
because the operating region is pretty small. However there might be
new users in the future who might rely on this number. Fix average
steal timer calculation by changing the formula from:

	avg_steal_timer = avg_steal_timer / 2 + steal_timer;

to the following:

	avg_steal_timer = (avg_steal_timer + steal_timer) / 2;

This ensures that avg_steal_timer is actually a naive average of steal
timer values. It now closely follows steal timer values but of course
in a smoother manner.

Fixes: 152e9b8676 ("s390/vtime: steal time exponential moving average")
Signed-off-by: Mete Durlu <meted@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26 18:22:24 -04:00
arch s390/vtime: fix average steal time calculation 2024-03-26 18:22:24 -04:00
block block: sed-opal: handle empty atoms when parsing response 2024-03-26 18:22:12 -04:00
certs
crypto crypto: api - Disallow identical driver names 2024-02-23 08:24:48 +01:00
Documentation media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
drivers octeontx2-af: Use matching wake_up API variant in CGX command interface 2024-03-26 18:22:24 -04:00
fs afs: Revert "afs: Hide silly-rename files from userspace" 2024-03-26 18:22:24 -04:00
include media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 14:34:30 -08:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel bpf: Fix stackmap overflow check on 32-bit arches 2024-03-26 18:22:17 -04:00
lib net: blackhole_dev: fix build warning for ethh set but not used 2024-03-26 18:22:15 -04:00
LICENSES
mm userfaultfd: fix mmap_changing checking in mfill_atomic_hugetlb 2024-03-01 13:13:33 +01:00
net net: sunrpc: Fix an off by one in rpc_sockaddr2uaddr() 2024-03-26 18:22:23 -04:00
samples media: rename VFL_TYPE_GRABBER to _VIDEO 2024-03-26 18:22:22 -04:00
scripts kconfig: fix infinite loop when expanding a macro at the end of file 2024-03-26 18:22:24 -04:00
security lsm: new security_file_ioctl_compat() hook 2024-02-23 08:25:15 +01:00
sound ALSA: usb-audio: Stop parsing channels bits when all channels are found. 2024-03-26 18:22:23 -04:00
tools perf stat: Avoid metric-only segv 2024-03-26 18:22:20 -04:00
usr
virt KVM: arm64: vgic-its: Test for valid IRQ in MOVALL handler 2024-03-01 13:13:32 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.272 2024-03-15 14:40:56 -04:00
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.