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Rafał Miłecki 752e5fcc2e bgmac: reduce max frame size to support just MTU 1500 
bgmac allocates new replacement buffer before handling each received
frame. Allocating & DMA-preparing 9724 B each time consumes a lot of CPU
time. Ideally bgmac should just respect currently set MTU but it isn't
the case right now. For now just revert back to the old limited frame
size.

This change bumps NAT masquerade speed by ~95%.

Since commit 8218f62c9c ("mm: page_frag: use initial zero offset for
page_frag_alloc_align()"), the bgmac driver fails to open its network
interface successfully and runs out of memory in the following call
stack:

bgmac_open
  -> bgmac_dma_init
    -> bgmac_dma_rx_skb_for_slot
      -> netdev_alloc_frag

BGMAC_RX_ALLOC_SIZE = 10048 and PAGE_FRAG_CACHE_MAX_SIZE = 32768.

Eventually we land into __page_frag_alloc_align() with the following
parameters across multiple successive calls:

__page_frag_alloc_align: fragsz=10048, align_mask=-1, size=32768, offset=0
__page_frag_alloc_align: fragsz=10048, align_mask=-1, size=32768, offset=10048
__page_frag_alloc_align: fragsz=10048, align_mask=-1, size=32768, offset=20096
__page_frag_alloc_align: fragsz=10048, align_mask=-1, size=32768, offset=30144

So in that case we do indeed have offset + fragsz (40192) > size (32768)
and so we would eventually return NULL. Reverting to the older 1500
bytes MTU allows the network driver to be usable again.

Fixes: 8c7da63978 ("bgmac: configure MTU and add support for frames beyond 8192 byte size")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
[florian: expand commit message about recent commits]
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20250127175159.1788246-1-florian.fainelli@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-01-29 18:57:42 -08:00
arch Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
block for-6.14/io_uring-20250119 2025-01-20 20:27:33 -08:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Kthreads affinity follow either of 4 existing different patterns: 2025-01-21 17:10:05 -08:00
Documentation documentation: networking: fix spelling mistakes 2025-01-27 14:26:06 -08:00
drivers bgmac: reduce max frame size to support just MTU 1500 2025-01-29 18:57:42 -08:00
fs lsm/stable-6.14 PR 20250121 2025-01-21 20:03:04 -08:00
include ipsec-2025-01-27 2025-01-27 15:15:12 -08:00
init Rust changes for v6.14 2025-01-21 17:48:03 -08:00
io_uring for-6.14/io_uring-20250119 2025-01-20 20:27:33 -08:00
ipc - The series "resource: A couple of cleanups" from Andy Shevchenko 2024-11-25 16:09:48 -08:00
kernel Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
lib Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm cachestat: fix page cache statistics permission checking 2025-01-21 20:30:19 -08:00
net vsock: Allow retrying on connect() failure 2025-01-29 18:50:37 -08:00
rust Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
samples Rust changes for v6.14 2025-01-21 17:48:03 -08:00
scripts Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
security selinux/stable-6.14 PR 20250121 2025-01-21 20:09:14 -08:00
sound drm next for 6.14-rc1 2025-01-21 16:09:47 -08:00
tools vsock/test: Add test for connect() retries 2025-01-29 18:50:37 -08:00
usr kbuild: Drop support for include/asm-<arch> in headers_check.pl 2024-12-21 11:43:17 +09:00
virt VFIO updates for v6.13 2024-11-27 12:57:03 -08:00
.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 Networking changes for 6.14. 2025-01-22 08:28:57 -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: remove Andy Gospodarek from bonding 2025-01-09 08:30:01 -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: add Paul Fertser as a NC-SI reviewer 2025-01-27 14:31:46 -08:00
Makefile Networking changes for 6.14. 2025-01-22 08:28:57 -08:00
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.