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Roman Gushchin f59adcf593 mm: memcg: add cacheline padding after lruvec in mem_cgroup_per_node
Oliver Sand reported a performance regression caused by commit
98c9daf5ae ("mm: memcg: guard memcg1-specific members of struct
mem_cgroup_per_node"), which puts some fields of the mem_cgroup_per_node
structure under the CONFIG_MEMCG_V1 config option.  Apparently it causes a
false cache sharing between lruvec and lru_zone_size members of the
structure.  Fix it by adding an explicit padding after the lruvec member.

Even though the padding is not required with CONFIG_MEMCG_V1 set, it seems
like the introduced memory overhead is not significant enough to warrant
another divergence in the mem_cgroup_per_node layout, so the padding is
added unconditionally.

Link: https://lkml.kernel.org/r/20240723171244.747521-1-roman.gushchin@linux.dev
Fixes: 98c9daf5ae ("mm: memcg: guard memcg1-specific members of struct mem_cgroup_per_node")
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202407121335.31a10cb6-oliver.sang@intel.com
Tested-by: Oliver Sang <oliver.sang@intel.com>
Acked-by: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-07-26 14:33:09 -07:00
arch sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-25 12:58:36 -07:00
block for-6.11/block-20240722 2024-07-22 11:32:05 -07:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
Documentation dt-bindings: arm: update James Clark's email address 2024-07-26 14:32:50 -07:00
drivers A lot of networking people were at a conference last week, busy 2024-07-25 13:32:25 -07:00
fs sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-25 12:58:36 -07:00
include mm: memcg: add cacheline padding after lruvec in mem_cgroup_per_node 2024-07-26 14:33:09 -07:00
init Kbuild updates for v6.11 2024-07-23 14:32:21 -07:00
io_uring io_uring: fix error pbuf checking 2024-07-20 11:04:57 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel A lot of networking people were at a conference last week, busy 2024-07-25 13:32:25 -07:00
lib decompress_bunzip2: fix rare decompression failure 2024-07-26 14:33:09 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm alloc_tag: outline and export free_reserved_page() 2024-07-26 14:33:09 -07:00
net A lot of networking people were at a conference last week, busy 2024-07-25 13:32:25 -07:00
rust This pull request contains the following changes for UML: 2024-07-25 12:33:08 -07:00
samples Driver core changes for 6.11-rc1 2024-07-25 10:42:22 -07:00
scripts This pull request contains the following changes for UML: 2024-07-25 12:33:08 -07:00
security sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
sound Driver core changes for 6.11-rc1 2024-07-25 10:42:22 -07:00
tools A lot of networking people were at a conference last week, busy 2024-07-25 13:32:25 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM generic changes for 6.11 2024-07-16 09:51:36 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.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: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap MAINTAINERS: mailmap: update James Clark's email address 2024-07-26 14:32:35 -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 tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -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 MAINTAINERS: mailmap: update James Clark's email address 2024-07-26 14:32:35 -07:00
Makefile Kbuild updates for v6.11 2024-07-23 14:32:21 -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.