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Rik van Riel fe0ea3084c ANDROID: add extra free kbytes tunable
Add a userspace visible knob to tell the VM to keep an extra amount
of memory free, by increasing the gap between each zone's min and
low watermarks.

This is useful for realtime applications that call system
calls and have a bound on the number of allocations that happen
in any short time period.  In this application, extra_free_kbytes
would be left at an amount equal to or larger than than the
maximum number of allocations that happen in any burst.

It may also be useful to reduce the memory use of virtual
machines (temporarily?), in a way that does not cause memory
fragmentation like ballooning does.

[ccross]
Revived for use on old kernels where no other solution exists.
The tunable will be removed on kernels that do better at avoiding
direct reclaim.

[surenb]
Will be reverted as soon as Android framework is reworked to
use upstream-supported watermark_scale_factor instead of
extra_free_kbytes.

Bug: 86445363
Bug: 109664768
Bug: 120445732
Change-Id: I765a42be8e964bfd3e2886d1ca85a29d60c3bb3e
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
2018-12-05 09:48:12 -08:00
arch ANDROID: cuttlefish_defconfig: Enable CONFIG_DM_VERITY_AVB 2018-12-05 09:48:12 -08:00
block block: Clear kernel memory before copying to user 2018-11-27 16:13:05 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: user - fix leaking uninitialized memory to userspace 2018-11-21 09:19:24 +01:00
Documentation ANDROID: add extra free kbytes tunable 2018-12-05 09:48:12 -08:00
drivers ANDROID: AVB error handler to invalidate vbmeta partition. 2018-12-05 09:48:12 -08:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs ANDROID: fs: FS tracepoints to track IO. 2018-12-05 09:48:12 -08:00
include ANDROID: fs: FS tracepoints to track IO. 2018-12-05 09:48:12 -08:00
init ANDROID: sched: fair/tune: Add schedtune with cgroups interface 2018-10-26 11:57:46 +01:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel ANDROID: add extra free kbytes tunable 2018-12-05 09:48:12 -08:00
lib lib/raid6: Fix arm64 test build 2018-11-27 16:13:05 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm ANDROID: add extra free kbytes tunable 2018-12-05 09:48:12 -08:00
net UPSTREAM: tcp: start receiver buffer autotuning sooner 2018-12-05 09:48:11 -08:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple 2018-12-05 09:47:58 -08:00
security apparmor: Fix uninitialized value in aa_split_fqname 2018-11-27 16:13:00 +01:00
sound ALSA: hda/ca0132 - Call pci_iounmap() instead of iounmap() 2018-11-27 16:13:09 +01:00
tools perf tools: Do not zero sample_id_all for group members 2018-11-27 16:13:06 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.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 libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
build.config.cuttlefish.aarch64 ANDROID: defconfig / build config for cuttlefish 2018-12-05 09:47:58 -08:00
build.config.cuttlefish.x86_64 ANDROID: defconfig / build config for cuttlefish 2018-12-05 09:47:58 -08:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add an entry for the code of conduct 2018-10-22 07:33:36 +01:00
Makefile ANDROID: Kbuild, LLVMLinux: allow overriding clang target triple 2018-12-05 09:47:58 -08:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.