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Charan Teja Kalla 9cd20f3fe0 mm: page_alloc: enforce minimum zone size to do high atomic reserves
Highatomic reserves are set to roughly 1% of zone for maximum and a
pageblock size for minimum.  Encountered a system with the below
configuration:
Normal free:7728kB boost:0kB min:804kB low:1004kB high:1204kB
reserved_highatomic:8192KB managed:49224kB

On such systems, even a single pageblock makes highatomic reserves are set
to ~8% of the zone memory.  This high value can easily exert pressure on
the zone.

Per discussion with Michal and Mel, it is not much useful to reserve the
memory for highatomic allocations on such small systems[1].  Since the
minimum size for high atomic reserves is always going to be a pageblock
size and if 1% of zone managed pages is going to be below pageblock size,
don't reserve memory for high atomic allocations.  Thanks Michal for this
suggestion[2].

Since no memory is being reserved for high atomic allocations and if
respective allocation failures are seen, this patch can be reverted.

[1] https://lore.kernel.org/linux-mm/20231117161956.d3yjdxhhm4rhl7h2@techsingularity.net/
[2] https://lore.kernel.org/linux-mm/ZVYRJMUitykepLRy@tiehlicka/

Link: https://lkml.kernel.org/r/c3a2a48e2cfe08176a80eaf01c110deb9e918055.1700821416.git.quic_charante@quicinc.com
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavankumar Kondeti <quic_pkondeti@quicinc.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-12-10 16:51:52 -08:00
arch NUMA: optimize detection of memory with no node id assigned by firmware 2023-12-10 16:51:34 -08:00
block fs: convert error_remove_page to error_remove_folio 2023-12-10 16:51:42 -08:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto This push fixes a regression in ahash and hides the Kconfig sub-options for the jitter RNG. 2023-11-09 17:04:58 -08:00
Documentation fs: convert error_remove_page to error_remove_folio 2023-12-10 16:51:42 -08:00
drivers zram: tweak writeback config help 2023-12-10 16:51:41 -08:00
fs fs/Kconfig: make hugetlbfs a menuconfig 2023-12-10 16:51:51 -08:00
include pgtable: rename ptdesc _refcount field to __page_refcount 2023-12-10 16:51:50 -08:00
init As usual, lots of singleton and doubleton patches all over the tree and 2023-11-02 20:53:31 -10:00
io_uring io_uring: use fget/fput consistently 2023-11-28 11:56:29 -07:00
ipc Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
kernel fork: use __mt_dup() to duplicate maple tree in dup_mmap() 2023-12-10 16:51:34 -08:00
lib lib/stackdepot: adjust DEPOT_POOLS_CAP for KMSAN 2023-12-10 16:51:48 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: page_alloc: enforce minimum zone size to do high atomic reserves 2023-12-10 16:51:52 -08:00
net wireless fixes: 2023-11-29 19:43:34 -08:00
rust Kbuild updates for v6.7 2023-11-04 08:07:19 -10:00
samples Landlock updates for v6.7-rc1 2023-11-03 09:28:53 -10:00
scripts Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
security + Features 2023-11-03 09:48:17 -10:00
sound ALSA: hda: Disable power-save on KONTRON SinglePC 2023-11-30 16:14:21 +01:00
tools selftests/mm: check that PAGEMAP_SCAN returns correct categories 2023-12-10 16:51:35 -08:00
usr arch: Remove Itanium (IA-64) architecture 2023-09-11 08:13:17 +00:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: generate kernel.spec in rpmbuild/SPECS/ 2023-10-03 20:49:09 +09:00
.mailmap .mailmap: add a new address mapping for Chester Lin 2023-12-06 16:12:45 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: drop Antti Palosaari 2023-12-06 16:12:49 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Merge branch 'master' into mm-hotfixes-stable 2023-12-06 17:03:50 -08:00
Makefile Linux 6.7-rc4 2023-12-03 18:52:56 +09:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -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.

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.