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Dev Jain d4202e66a4 selftests/mm: compaction_test: fix bogus test success on Aarch64
Patch series "Fixes for compaction_test", v2.

The compaction_test memory selftest introduces fragmentation in memory
and then tries to allocate as many hugepages as possible. This series
addresses some problems.

On Aarch64, if nr_hugepages == 0, then the test trivially succeeds since
compaction_index becomes 0, which is less than 3, due to no division by
zero exception being raised. We fix that by checking for division by
zero.

Secondly, correctly set the number of hugepages to zero before trying
to set a large number of them.

Now, consider a situation in which, at the start of the test, a non-zero
number of hugepages have been already set (while running the entire
selftests/mm suite, or manually by the admin). The test operates on 80%
of memory to avoid OOM-killer invocation, and because some memory is
already blocked by hugepages, it would increase the chance of OOM-killing.
Also, since mem_free used in check_compaction() is the value before we
set nr_hugepages to zero, the chance that the compaction_index will
be small is very high if the preset nr_hugepages was high, leading to a
bogus test success.


This patch (of 3):

Currently, if at runtime we are not able to allocate a huge page, the test
will trivially pass on Aarch64 due to no exception being raised on
division by zero while computing compaction_index.  Fix that by checking
for nr_hugepages == 0.  Anyways, in general, avoid a division by zero by
exiting the program beforehand.  While at it, fix a typo, and handle the
case where the number of hugepages may overflow an integer.

Link: https://lkml.kernel.org/r/20240521074358.675031-1-dev.jain@arm.com
Link: https://lkml.kernel.org/r/20240521074358.675031-2-dev.jain@arm.com
Fixes: bd67d5c15c ("Test compaction of mlocked memory")
Signed-off-by: Dev Jain <dev.jain@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Sri Jayaramappa <sjayaram@akamai.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-05-24 11:55:05 -07:00
arch - A series ("kbuild: enable more warnings by default") from Arnd 2024-05-22 18:59:29 -07:00
block Compactifying bdev flags 2024-05-21 13:02:56 -07:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto This push fixes a bug in the new ecc P521 code as well as a buggy 2024-05-20 08:47:54 -07:00
Documentation lib: add version into /proc/allocinfo output 2024-05-24 11:55:05 -07:00
drivers - A series ("kbuild: enable more warnings by default") from Arnd 2024-05-22 18:59:29 -07:00
fs - A series ("kbuild: enable more warnings by default") from Arnd 2024-05-22 18:59:29 -07:00
include kasan, fortify: properly rename memintrinsics 2024-05-24 11:55:05 -07:00
init Driver core changes for 6.10-rc1 2024-05-22 12:13:40 -07:00
io_uring Assorted commits that had missed the last merge window... 2024-05-21 13:11:44 -07:00
ipc Mainly singleton patches, documented in their respective changelogs. 2024-05-19 14:02:03 -07:00
kernel Driver core changes for 6.10-rc1 2024-05-22 12:13:40 -07:00
lib lib: add version into /proc/allocinfo output 2024-05-24 11:55:05 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm/huge_memory: don't unpoison huge_zero_folio 2024-05-24 11:55:05 -07:00
net more s390 updates for 6.10 merge window 2024-05-21 12:09:36 -07:00
rust LoongArch changes for v6.10 2024-05-22 09:43:07 -07:00
samples Char/Misc and other driver subsystem changes for 6.10-rc1 2024-05-22 12:26:46 -07:00
scripts - A series ("kbuild: enable more warnings by default") from Arnd 2024-05-22 18:59:29 -07:00
security KEYS: trusted: Do not use WARN when encode fails 2024-05-21 02:35:10 +03:00
sound - Core Frameworks 2024-05-22 10:49:54 -07:00
tools selftests/mm: compaction_test: fix bogus test success on Aarch64 2024-05-24 11:55:05 -07:00
usr kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
virt The usual shower of singleton fixes and minor series all over MM, 2024-05-19 09:21:03 -07:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: create a list of all built DTB files 2024-02-19 18:20:39 +09:00
.mailmap mailmap: update email address for Satya Priya 2024-05-24 11:55:05 -07:00
.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 Gustavo Pimentel as PCI DWC Maintainer 2024-03-27 13:41:02 -05:00
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 Char/Misc and other driver subsystem changes for 6.10-rc1 2024-05-22 12:26:46 -07:00
Makefile arch: add ARCH_HAS_KERNEL_FPU_SUPPORT 2024-05-19 14:36:17 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -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 reStructuredText 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.