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Mainline Linux tree for various devices, only for fun :)
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Patrick Bellasi 295f1a9953 cpufreq: schedutil: Fix iowait boost reset 
A more energy efficient update of the IO wait boosting mechanism has
been introduced in:

   commit a5a0809bc5 ("cpufreq: schedutil: Make iowait boost more energy efficient")

where the boost value is expected to be:

 - doubled at each successive wakeup from IO
   staring from the minimum frequency supported by a CPU

 - reset when a CPU is not updated for more then one tick
   by either disabling the IO wait boost or resetting its value to the
   minimum frequency if this new update requires an IO boost.

This approach is supposed to "ignore" boosting for sporadic wakeups from
IO, while still getting the frequency boosted to the maximum to benefit
long sequence of wakeup from IO operations.

However, these assumptions are not always satisfied.
For example, when an IO boosted CPU enters idle for more the one tick
and then wakes up after an IO wait, since in sugov_set_iowait_boost() we
first check the IOWAIT flag, we keep doubling the iowait boost instead
of restarting from the minimum frequency value.

This misbehavior could happen mainly on non-shared frequency domains,
thus defeating the energy efficiency optimization, but it can also
happen on shared frequency domain systems.

Let fix this issue in sugov_set_iowait_boost() by:
 - first check the IO wait boost reset conditions
   to eventually reset the boost value
 - then applying the correct IO boost value
   if required by the caller

Fixes: a5a0809bc5 (cpufreq: schedutil: Make iowait boost more energy efficient)
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-05-22 14:05:05 +02:00
arch Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-13 10:53:08 -07:00
block blk-mq: fix sysfs inflight counter 2018-04-26 09:02:01 -06:00
certs certs/blacklist_nohashes.c: fix const confusion in certs blacklist 2018-02-21 15:35:43 -08:00
crypto crypto: drbg - set freed buffers to NULL 2018-04-21 00:57:00 +08:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-11 14:14:46 -07:00
drivers Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux 2018-05-12 10:58:57 -07:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs some small SMB3 fixes for 4.17-rc5, some for stable 2018-05-12 18:49:53 -07:00
include Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-13 10:53:08 -07:00
init init: fix false positives in W+X checking 2018-05-11 17:28:45 -07:00
ipc ipc/shm: fix use-after-free of shm file via remap_file_pages() 2018-04-13 17:10:27 -07:00
kernel cpufreq: schedutil: Fix iowait boost reset 2018-05-22 14:05:05 +02:00
lib another dma-mapping fix for 4.17-rc: 2018-05-13 10:28:53 -07:00
LICENSES LICENSES: Add MPL-1.1 license 2018-01-06 10:59:44 -07:00
mm Merge branch 'akpm' (patches from Andrew) 2018-05-11 18:04:12 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2018-05-11 14:14:46 -07:00
samples bpf: sockmap sample use clang flag, -target bpf 2018-04-23 23:42:21 +02:00
scripts scripts/faddr2line: fix error when addr2line output contains discriminator 2018-05-11 17:28:45 -07:00
security Merge branch 'userns-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2018-04-24 17:58:51 -07:00
sound ALSA: pcm: Check PCM state at xfern compat ioctl 2018-05-02 08:54:54 +02:00
tools Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-05-13 10:44:32 -07:00
usr kbuild: rename built-in.o to built-in.a 2018-03-26 02:01:19 +09:00
virt KVM/arm fixes for 4.17, take #2 2018-05-05 23:05:31 +02:00
.clang-format clang-format: add configuration file 2018-04-11 10:28:35 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap Merge candidates for 4.17 merge window 2018-04-06 17:35:43 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS MAINTAINERS/CREDITS: Drop METAG ARCHITECTURE 2018-03-05 16:34:24 +00:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
MAINTAINERS Merge branch 'akpm' (patches from Andrew) 2018-05-11 18:04:12 -07:00
Makefile Linux 4.17-rc5 2018-05-13 16:15:17 -07:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.