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Daniel Xu 23dc986732 bpf, cpumap: Move xdp:xdp_cpumap_kthread tracepoint before rcv
cpumap takes RX processing out of softirq and onto a separate kthread.
Since the kthread needs to be scheduled in order to run (versus softirq
which does not), we can theoretically experience extra latency if the
system is under load and the scheduler is being unfair to us.

Moving the tracepoint to before passing the skb list up the stack allows
users to more accurately measure enqueue/dequeue latency introduced by
cpumap via xdp:xdp_cpumap_enqueue and xdp:xdp_cpumap_kthread tracepoints.

f9419f7bd7 ("bpf: cpumap add tracepoints") which added the tracepoints
states that the intent behind them was for general observability and for
a feedback loop to see if the queues are being overwhelmed. This change
does not mess with either of those use cases but rather adds a third
one.

Signed-off-by: Daniel Xu <dxu@dxuuu.xyz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://lore.kernel.org/bpf/47615d5b5e302e4bd30220473779e98b492d47cd.1725585718.git.dxu@dxuuu.xyz
2024-09-11 16:32:11 +02:00
arch Driver core fixes for 6.11-rc4 2024-08-18 10:19:49 -07:00
block block: Fix lockdep warning in blk_mq_mark_tag_wait 2024-08-15 19:25:03 -06:00
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 dpll: add Embedded SYNC feature for a pin 2024-08-26 19:21:14 -07:00
drivers netkit: Disable netpoll support 2024-08-27 11:37:45 -07:00
fs Changes since last update: 2024-08-22 06:06:09 +08:00
include dpll: add Embedded SYNC feature for a pin 2024-08-26 19:21:14 -07:00
init Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
io_uring io_uring/sqpoll: annotate debug task == current with data_race() 2024-08-13 06:10:59 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel bpf, cpumap: Move xdp:xdp_cpumap_kthread tracepoint before rcv 2024-09-11 16:32:11 +02:00
lib bcachefs fixes for 6.11-rc4 2024-08-17 09:46:10 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm 16 hotfixes. All except one are for MM. 10 of these are cc:stable and 2024-08-17 19:50:16 -07:00
net xsk: Bump xsk_queue::queue_empty_descs in xp_can_alloc() 2024-09-05 15:56:49 +02:00
rust Rust fixes for v6.11 2024-08-16 11:24:06 -07:00
samples treewide: remove unnecessary <linux/version.h> inclusion 2024-08-12 18:36:44 +09:00
scripts Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
security KEYS: trusted: dcp: fix leak of blob encryption key 2024-08-15 22:01:14 +03:00
sound Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
tools selftests/xsk: Read current MAX_SKB_FRAGS from sysctl knob 2024-09-11 15:48:35 +02:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM: x86: Disallow read-only memslots for SEV-ES and SEV-SNP (and TDX) 2024-08-14 12:28:24 -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 .gitignore: add .gcda files 2024-08-09 13:18:46 +01:00
.mailmap mailmap: update entry for David Heidelberg 2024-08-07 18:33:56 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING
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 net: netconsole: selftests: Create a new netconsole selftest 2024-08-26 09:27:15 -07:00
Makefile Kbuild fixes for v6.11 (2nd) 2024-08-23 07:43:15 +08:00
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.