1
0
Fork 0
mirror of synced 2025-03-06 20:59:54 +01:00
Linux kernel source tree
Find a file
Jakub Kicinski f5da7c4518 tcp: adjust rcvq_space after updating scaling ratio
Since commit under Fixes we set the window clamp in accordance
to newly measured rcvbuf scaling_ratio. If the scaling_ratio
decreased significantly we may put ourselves in a situation
where windows become smaller than rcvq_space, preventing
tcp_rcv_space_adjust() from increasing rcvbuf.

The significant decrease of scaling_ratio is far more likely
since commit 697a6c8cec ("tcp: increase the default TCP scaling ratio"),
which increased the "default" scaling ratio from ~30% to 50%.

Hitting the bad condition depends a lot on TCP tuning, and
drivers at play. One of Meta's workloads hits it reliably
under following conditions:
 - default rcvbuf of 125k
 - sender MTU 1500, receiver MTU 5000
 - driver settles on scaling_ratio of 78 for the config above.
Initial rcvq_space gets calculated as TCP_INIT_CWND * tp->advmss
(10 * 5k = 50k). Once we find out the true scaling ratio and
MSS we clamp the windows to 38k. Triggering the condition also
depends on the message sequence of this workload. I can't repro
the problem with simple iperf or TCP_RR-style tests.

Fixes: a2cbb16039 ("tcp: Update window clamping condition")
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20250217232905.3162187-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-02-18 16:02:18 -08:00
arch LoongArch fixes for v6.14-rc3 2025-02-13 08:43:46 -08:00
block block-6.14-20250131 2025-01-31 11:49:30 -08:00
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 Including fixes from netfilter, wireless and bluetooth. 2025-02-13 12:17:04 -08:00
drivers ibmvnic: Don't reference skb after sending to VIOS 2025-02-17 16:41:57 -08:00
fs for-6.14-rc2-tag 2025-02-13 12:06:29 -08:00
include Including fixes from netfilter, wireless and bluetooth. 2025-02-13 12:17:04 -08:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring Fix a dangling pointer bug in the futex code used by the 2025-02-08 10:54:11 -08:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel seccomp fix for v6.14-rc2 2025-02-08 14:04:21 -08:00
lib hardening fixes for v6.14-rc2 2025-02-08 14:12:17 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm assorted stuff for this merge window 2025-02-01 15:07:56 -08:00
net tcp: adjust rcvq_space after updating scaling ratio 2025-02-18 16:02:18 -08:00
rust rust: kbuild: do not export generated KASAN ODR symbols 2025-02-06 19:47:04 +01:00
samples hid-for-linus-2025021001 2025-02-10 09:50:01 -08:00
scripts Kbuild fixes for v6.14 2025-02-09 10:05:32 -08:00
security Redo of pathname patternization and fix spelling errors. 2025-02-11 10:19:36 -08:00
sound sound fixes for 6.14-rc1 2025-01-31 09:17:02 -08:00
tools selftest/bpf: Add vsock test for sockmap rejecting unconnected 2025-02-18 12:00:01 +01:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +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 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 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 wireless fixes for v6.14-rc3 2025-02-10 18:13:07 -08:00
.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: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
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: create entry for ethtool MAC merge 2025-02-17 16:52:07 -08:00
Makefile Linux 6.14-rc2 2025-02-09 12:45:03 -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.