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Jakub Kicinski 34ea1df802 Merge branch 'net-mlx5-hw-counters-refactor' 
Tariq Toukan says:

====================
net/mlx5: hw counters refactor

This is a patchset re-post, see:
https://lore.kernel.org/20240815054656.2210494-7-tariqt@nvidia.com

In this patchset, Cosmin refactors hw counters and solves perf scaling
issue.

Series generated against:
commit c824deb1a8 ("cxgb4: clip_tbl: Fix spelling mistake "wont" -> "won't"")

HW counters are central to mlx5 driver operations. They are hardware
objects created and used alongside most steering operations, and queried
from a variety of places. Most counters are queried in bulk from a
periodic task in fs_counters.c.

Counter performance is important and as such, a variety of improvements
have been done over the years. Currently, counters are allocated from
pools, which are bulk allocated to amortize the cost of firmware
commands. Counters are managed through an IDR, a doubly linked list and
two atomic single linked lists. Adding/removing counters is a complex
dance between user contexts requesting it and the mlx5_fc_stats_work
task which does most of the work.

Under high load (e.g. from connection tracking flow insertion/deletion),
the counter code becomes a bottleneck, as seen on flame graphs. Whenever
a counter is deleted, it gets added to a list and the wq task is
scheduled to run immediately to actually delete it. This is done via
mod_delayed_work which uses an internal spinlock. In some tests, waiting
for this spinlock took up to 66% of all samples.

This series refactors the counter code to use a more straight-forward
approach, avoiding the mod_delayed_work problem and making the code
easier to understand. For that:

- patch #1 moves counters data structs to a more appropriate place.
- patch #2 simplifies the bulk query allocation scheme by using vmalloc.
- patch #3 replaces the IDR+3 lists with an xarray. This is the main
  patch of the series, solving the spinlock congestion issue.
- patch #4 removes an unnecessary cacheline alignment causing a lot of
  memory to be wasted.
- patches #5 and #6 are small cleanups enabled by the refactoring.
====================

Link: https://patch.msgid.link/20241001103709.58127-1-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-04 11:33:48 -07:00
arch move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
block move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
Documentation lib: packing: adjust definitions and implementation for arbitrary buffer lengths 2024-10-03 15:32:03 -07:00
drivers net/mlx5: hw counters: Remove mlx5_fc_create_ex 2024-10-04 11:33:47 -07:00
fs three small ksmbd server fixes 2024-10-03 09:38:16 -07:00
include net/mlx5: hw counters: Remove mlx5_fc_create_ex 2024-10-04 11:33:47 -07:00
init Rust changes for v6.12 2024-09-25 10:25:40 -07:00
io_uring for-6.12/io_uring-20240922 2024-09-24 11:11:38 -07:00
ipc struct fd layout change (and conversion to accessor helpers) 2024-09-23 09:35:36 -07:00
kernel Getting rid of asm/unaligned.h includes 2024-10-02 16:42:28 -07:00
lib lib: packing: use GENMASK() for box_mask 2024-10-03 15:32:04 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm 19 hotfixes. 13 are cc:stable. 2024-09-27 10:27:22 -07:00
net appletalk: Remove deadcode 2024-10-04 12:42:32 +01:00
rust rust: net::phy always define device_table in module_phy_driver macro 2024-10-03 16:42:18 -07:00
samples [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
scripts Reduce Coccinelle choices in string_choices.cocci 2024-09-28 21:33:11 +02:00
security move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
sound move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
tools selftests: net: csum: Clean up recv_verify_packet_ipv6 2024-10-03 16:44:28 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt x86: 2024-09-28 09:20:14 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.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 updates for v6.12 2024-09-24 13:02:06 -07:00
.mailmap Summary 2024-09-24 11:08:40 -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: Mark powerpc spufs as orphaned 2024-08-19 21:27:56 +10:00
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 lib: packing: add KUnit tests adapted from selftests 2024-10-03 15:32:04 -07:00
Makefile Linux 6.12-rc1 2024-09-29 15:06:19 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

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.