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Yonghong Song says: ==================== Commita26ca7c982("bpf: btf: Add pretty print support to the basic arraymap") and Commit699c86d6ec("bpf: btf: add pretty print for hash/lru_hash maps") added bpffs pretty print for array, hash and lru hash maps. The pretty print gives users a structurally formatted dump for keys/values which much easy to understand than raw bytes. This patch set implemented bpffs pretty print support for percpu arraymap, percpu hashmap and percpu lru hashmap. For complex key/value types, the pretty print here is even more useful due to: . large volumne of data making it even harder to correlate bytes to a particular field in a particular cpu. . kernel rounds the value size for each cpu to multiple of 8. User has to be aware of this otherwise wrong value may be derived from cpu 1/2/... For example, we may have a bpffs pretty print like below: 43602: { cpu0: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO} cpu1: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO} cpu2: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO} cpu3: {43602,0,-43602,0x3,0xaa52,0x3,{43602|[82,170,0,0,0,0,0,0]},ENUM_TWO} } for a percpu map. This patch also added percpu formatted print on bpftool. For example, bpftool may print like below: { "key": 0, "values": [{ "cpu": 0, "value": { "ui32": 0, "ui16": 0, } },{ "cpu": 1, "value": { "ui32": 1, "ui16": 0, } },{ "cpu": 2, "value": { "ui32": 2, "ui16": 0, } },{ "cpu": 3, "value": { "ui32": 3, "ui16": 0, } } ] } Patch #1 implemented bpffs pretty print for percpu arraymap/hash/lru_hash in kernel. Patch #2 added the test case in tools bpf selftest test_btf. Patch #3 added percpu map btf based dump. ==================== Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.