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Jakub Kicinski bf2468f9af Merge branch 'locking-introduce-nested-bh-locking' Sebastian Andrzej Siewior says: ==================== locking: Introduce nested-BH locking. Disabling bottoms halves acts as per-CPU BKL. On PREEMPT_RT code within local_bh_disable() section remains preemtible. As a result high prior tasks (or threaded interrupts) will be blocked by lower-prio task (or threaded interrupts) which are long running which includes softirq sections. The proposed way out is to introduce explicit per-CPU locks for resources which are protected by local_bh_disable() and use those only on PREEMPT_RT so there is no additional overhead for !PREEMPT_RT builds. The series introduces the infrastructure and converts large parts of networking which is largest stake holder here. Once this done the per-CPU lock from local_bh_disable() on PREEMPT_RT can be lifted. Performance testing. Baseline is net-next as of commit `93bda33046` ("Merge branch'net-constify-ctl_table-arguments-of-utility-functions'") plus v6.10-rc1. A 10GiG link is used between two hosts. The command xdp-bench redirect-cpu --cpu 3 --remote-action drop eth1 -e was invoked on the receiving side with a ixgbe. The sending side uses pktgen_sample03_burst_single_flow.sh on i40e. Baseline: \| eth1->? 9,018,604 rx/s 0 err,drop/s \| receive total 9,018,604 pkt/s 0 drop/s 0 error/s \| cpu:7 9,018,604 pkt/s 0 drop/s 0 error/s \| enqueue to cpu 3 9,018,602 pkt/s 0 drop/s 7.00 bulk-avg \| cpu:7->3 9,018,602 pkt/s 0 drop/s 7.00 bulk-avg \| kthread total 9,018,606 pkt/s 0 drop/s 214,698 sched \| cpu:3 9,018,606 pkt/s 0 drop/s 214,698 sched \| xdp_stats 0 pass/s 9,018,606 drop/s 0 redir/s \| cpu:3 0 pass/s 9,018,606 drop/s 0 redir/s \| redirect_err 0 error/s \| xdp_exception 0 hit/s perf top --sort cpu,symbol --no-children: \| 18.14% 007 [k] bpf_prog_4f0ffbb35139c187_cpumap_l4_hash \| 13.29% 007 [k] ixgbe_poll \| 12.66% 003 [k] cpu_map_kthread_run \| 7.23% 003 [k] page_frag_free \| 6.76% 007 [k] xdp_do_redirect \| 3.76% 007 [k] cpu_map_redirect \| 3.13% 007 [k] bq_flush_to_queue \| 2.51% 003 [k] xdp_return_frame \| 1.93% 007 [k] try_to_wake_up \| 1.78% 007 [k] _raw_spin_lock \| 1.74% 007 [k] cpu_map_enqueue \| 1.56% 003 [k] bpf_prog_57cd311f2e27366b_cpumap_drop With this series applied: \| eth1->? 10,329,340 rx/s 0 err,drop/s \| receive total 10,329,340 pkt/s 0 drop/s 0 error/s \| cpu:6 10,329,340 pkt/s 0 drop/s 0 error/s \| enqueue to cpu 3 10,329,338 pkt/s 0 drop/s 8.00 bulk-avg \| cpu:6->3 10,329,338 pkt/s 0 drop/s 8.00 bulk-avg \| kthread total 10,329,321 pkt/s 0 drop/s 96,297 sched \| cpu:3 10,329,321 pkt/s 0 drop/s 96,297 sched \| xdp_stats 0 pass/s 10,329,321 drop/s 0 redir/s \| cpu:3 0 pass/s 10,329,321 drop/s 0 redir/s \| redirect_err 0 error/s \| xdp_exception 0 hit/s perf top --sort cpu,symbol --no-children: \| 20.90% 006 [k] bpf_prog_4f0ffbb35139c187_cpumap_l4_hash \| 12.62% 006 [k] ixgbe_poll \| 9.82% 003 [k] page_frag_free \| 8.73% 003 [k] cpu_map_bpf_prog_run_xdp \| 6.63% 006 [k] xdp_do_redirect \| 4.94% 003 [k] cpu_map_kthread_run \| 4.28% 006 [k] cpu_map_redirect \| 4.03% 006 [k] bq_flush_to_queue \| 3.01% 003 [k] xdp_return_frame \| 1.95% 006 [k] _raw_spin_lock \| 1.94% 003 [k] bpf_prog_57cd311f2e27366b_cpumap_drop This diff appears to be noise. v8: https://lore.kernel.org/all/20240619072253.504963-1-bigeasy@linutronix.de v7: https://lore.kernel.org/all/20240618072526.379909-1-bigeasy@linutronix.de v6: https://lore.kernel.org/all/20240612170303.3896084-1-bigeasy@linutronix.de v5: https://lore.kernel.org/all/20240607070427.1379327-1-bigeasy@linutronix.de v4: https://lore.kernel.org/all/20240604154425.878636-1-bigeasy@linutronix.de v3: https://lore.kernel.org/all/20240529162927.403425-1-bigeasy@linutronix.de v2: https://lore.kernel.org/all/20240503182957.1042122-1-bigeasy@linutronix.de v1: https://lore.kernel.org/all/20231215171020.687342-1-bigeasy@linutronix.de ==================== Link: https://patch.msgid.link/20240620132727.660738-1-bigeasy@linutronix.de Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2024-06-24 16:41:26 -07:00
arch	ARM: dts: rockchip: rk3xxx: fix emac node	2024-06-21 10:07:17 +01:00
block	block: unmap and free user mapped integrity via submitter	2024-06-12 11:00:50 -06:00
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	linux-can-next-for-6.11-20240621	2024-06-21 18:06:41 -07:00
drivers	Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue	2024-06-23 12:50:19 +01:00
fs	19 hotfixes, 8 of which are cc:stable.	2024-06-17 12:30:07 -07:00
include	net: Move per-CPU flush-lists to bpf_net_context on PREEMPT_RT.	2024-06-24 16:41:24 -07:00
init	gcc: disable '-Warray-bounds' for gcc-9	2024-06-15 10:43:04 -07:00
io_uring	io_uring: fix cancellation overwriting req->flags	2024-06-13 19:25:28 -06:00
ipc	Mainly singleton patches, documented in their respective changelogs.	2024-05-19 14:02:03 -07:00
kernel	net: Move per-CPU flush-lists to bpf_net_context on PREEMPT_RT.	2024-06-24 16:41:24 -07:00
lib	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2024-06-20 13:49:59 -07:00
LICENSES	LICENSES: Add the copyleft-next-0.3.1 license	2022-11-08 15:44:01 +01:00
mm	19 hotfixes, 8 of which are cc:stable.	2024-06-17 12:30:07 -07:00
net	net: Move per-CPU flush-lists to bpf_net_context on PREEMPT_RT.	2024-06-24 16:41:24 -07:00
rust	LoongArch changes for v6.10	2024-05-22 09:43:07 -07:00
samples	bpf-next-for-netdev	2024-05-28 07:27:29 -07:00
scripts	Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net	2024-06-13 13:13:46 -07:00
security	lsm/stable-6.10 PR 20240617	2024-06-17 18:35:12 -07:00
sound	ALSA: hda: cs35l56: Select SERIAL_MULTI_INSTANTIATE	2024-06-20 09:58:25 +02:00
tools	selftests: net: change shebang to bash in amt.sh	2024-06-21 14:27:22 +01:00
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	.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: create a list of all built DTB files	2024-02-19 18:20:39 +09:00
.mailmap	bpf-for-netdev	2024-06-14 17:57:10 -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	MAINTAINERS: adjust file entry in FREESCALE QORIQ DPAA FMAN DRIVER	2024-06-24 11:34:39 +01:00
Makefile	Linux 6.10-rc4	2024-06-16 13:40:16 -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.