56b48c6a60
Yonghong Song says:
====================
Commit a26ca7c982cb ("bpf: btf: Add pretty print support to the
basic arraymap") and Commit 699c86d6ec21 ("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.