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Some protocols (e.g., TCP, UDP) implement memory accounting for socket buffers and charge memory to per-protocol global counters pointed to by sk->sk_proto->memory_allocated. Sometimes, system processes do not want that limitation. For a similar purpose, there is SO_RESERVE_MEM for sockets under memcg. Also, by opting out of the per-protocol accounting, sockets under memcg can avoid paying costs for two orthogonal memory accounting mechanisms. A microbenchmark result is in the subsequent bpf patch. Let's allow opt-out from the per-protocol memory accounting if sk->sk_bypass_prot_mem is true. sk->sk_bypass_prot_mem and sk->sk_prot are placed in the same cache line, and sk_has_account() always fetches sk->sk_prot before accessing sk->sk_bypass_prot_mem, so there is no extra cache miss for this patch. The following patches will set sk->sk_bypass_prot_mem to true, and then, the per-protocol memory accounting will be skipped. Note that this does NOT disable memcg, but rather the per-protocol one. Another option not to use the hole in struct sock_common is create sk_prot variants like tcp_prot_bypass, but this would complicate SOCKMAP logic, tcp_bpf_prots etc. Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Reviewed-by: Shakeel Butt <shakeel.butt@linux.dev> Reviewed-by: Eric Dumazet <edumazet@google.com> Acked-by: Roman Gushchin <roman.gushchin@linux.dev> Link: https://patch.msgid.link/20251014235604.3057003-3-kuniyu@google.com |
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| crypto | ||
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| drivers | ||
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| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
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| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
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| MAINTAINERS | ||
| Makefile | ||
| 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.