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Alexei Starovoitov says: ==================== bpf: Introduce BPF arena. From: Alexei Starovoitov <ast@kernel.org> v2->v3: - contains bpf bits only, but cc-ing past audience for continuity - since prerequisite patches landed, this series focus on the main functionality of bpf_arena. - adopted Andrii's approach to support arena in libbpf. - simplified LLVM support. Instead of two instructions it's now only one. - switched to cond_break (instead of open coded iters) in selftests - implemented several follow-ups that will be sent after this set . remember first IP and bpf insn that faulted in arena. report to user space via bpftool . copy paste and tweak glob_match() aka mini-regex as a selftests/bpf - see patch 1 for detailed description of bpf_arena v1->v2: - Improved commit log with reasons for using vmap_pages_range() in arena. Thanks to Johannes - Added support for __arena global variables in bpf programs - Fixed race conditions spotted by Barret - Fixed wrap32 issue spotted by Barret - Fixed bpf_map_mmap_sz() the way Andrii suggested The work on bpf_arena was inspired by Barret's work: https://github.com/google/ghost-userspace/blob/main/lib/queue.bpf.h that implements queues, lists and AVL trees completely as bpf programs using giant bpf array map and integer indices instead of pointers. bpf_arena is a sparse array that allows to use normal C pointers to build such data structures. Last few patches implement page_frag allocator, link list and hash table as bpf programs. v1: bpf programs have multiple options to communicate with user space: - Various ring buffers (perf, ftrace, bpf): The data is streamed unidirectionally from bpf to user space. - Hash map: The bpf program populates elements, and user space consumes them via bpf syscall. - mmap()-ed array map: Libbpf creates an array map that is directly accessed by the bpf program and mmap-ed to user space. It's the fastest way. Its disadvantage is that memory for the whole array is reserved at the start. ==================== Link: https://lore.kernel.org/r/20240308010812.89848-1-alexei.starovoitov@gmail.com Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
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 Restructured Text 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.