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Brendan Jackman e47f1f56dd mm/page_alloc: clarify terminology in migratetype fallback code
Patch series "mm/page_alloc: Some clarifications for migratetype
fallback", v4.

A couple of patches to try and make the code easier to follow.


This patch (of 2):

This code is rather confusing because:

 1. "Steal" is sometimes used to refer to the general concept of
    allocating from a from a block of a fallback migratetype
    (steal_suitable_fallback()) but sometimes it refers specifically to
    converting a whole block's migratetype (can_steal_fallback()).

 2. can_steal_fallback() sounds as though it's answering the question "am
    I functionally permitted to allocate from that other type" but in
    fact it is encoding a heuristic preference.

 3. The same piece of data has different names in different places:
    can_steal vs whole_block. This reinforces point 2 because it looks
    like the different names reflect a shift in intent from "am I
    allowed to steal" to "do I want to steal", but no such shift exists.

Fix 1. by avoiding the term "steal" in ambiguous contexts. Start using
the term "claim" to refer to the special case of stealing the entire
block.

Fix 2. by using "should" instead of "can", and also rename its
parameters and add some commentary to make it more explicit what they
mean.

Fix 3. by adopting the new "claim" terminology universally for this
set of variables.

Link: https://lkml.kernel.org/r/20250228-clarify-steal-v4-0-cb2ef1a4e610@google.com
Link: https://lkml.kernel.org/r/20250228-clarify-steal-v4-1-cb2ef1a4e610@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yosry Ahmed <yosry.ahmed@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 00:05:35 -07:00
arch Revert "x86/xen: allow nesting of same lazy mode" 2025-03-17 00:05:35 -07:00
block block-6.14-20250306 2025-03-07 11:12:33 -10:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation Docs/admin-guide/mm/damon/usage: add intervals_goal directory on the hierarchy 2025-03-17 00:05:34 -07:00
drivers zram: add might_sleep to zcomp API 2025-03-16 22:06:37 -07:00
fs fs/proc/task_mmu: reduce scope of lazy mmu region 2025-03-17 00:05:34 -07:00
include mm: fix lazy mmu docs and usage 2025-03-17 00:05:34 -07:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring io_uring-6.14-20250306 2025-03-07 11:09:33 -10:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel configs: drop GENERIC_PTDUMP from debug.config 2025-03-17 00:05:30 -07:00
lib lib/test_hmm: make dmirror_atomic_map() consume a single page 2025-03-17 00:05:29 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/page_alloc: clarify terminology in migratetype fallback code 2025-03-17 00:05:35 -07:00
net percpu: use TYPEOF_UNQUAL() in variable declarations 2025-03-16 22:05:53 -07:00
rust Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
samples samples/damon: a typo in the kconfig - sameple 2025-03-17 00:05:29 -07:00
scripts kbuild: install-extmod-build: Fix build when specifying KBUILD_OUTPUT 2025-03-06 20:32:30 +09:00
security Landlock fix for v6.14-rc5 2025-02-26 11:55:44 -08:00
sound ALSA: hda/realtek: Add support for ASUS Zenbook UM3406KA Laptops using CS35L41 HDA 2025-03-05 19:52:56 +01:00
tools tools/selftests: add guard region test for /proc/$pid/pagemap 2025-03-16 22:06:41 -07:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap 33 hotfixes. 24 are cc:stable and the remainder address post-6.13 issues 2025-03-08 14:34:06 -10:00
.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 mm: zbud: remove zbud 2025-03-16 22:06:01 -07:00
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 vmalloc: drop Christoph from Reviewers 2025-03-16 22:06:44 -07:00
Makefile Linux 6.14-rc6 2025-03-09 13:45:25 -10:00
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.