kernel_optimize_test/tools/lib
Andrey Ignatov 1a11a4c74f libbpf: Introduce bpf_map__resize
Add bpf_map__resize() to change max_entries for a map.

Quite often necessary map size is unknown at compile time and can be
calculated only at run time.

Currently the following approach is used to do so:
* bpf_object__open_buffer() to open Elf file from a buffer;
* bpf_object__find_map_by_name() to find relevant map;
* bpf_map__def() to get map attributes and create struct
  bpf_create_map_attr from them;
* update max_entries in bpf_create_map_attr;
* bpf_create_map_xattr() to create new map with updated max_entries;
* bpf_map__reuse_fd() to replace the map in bpf_object with newly
  created one.

And after all this bpf_object can finally be loaded. The map will have
new size.

It 1) is quite a lot of steps; 2) doesn't take BTF into account.

For "2)" even more steps should be made and some of them require changes
to libbpf (e.g. to get struct btf * from bpf_object).

Instead the whole problem can be solved by introducing simple
bpf_map__resize() API that checks the map and sets new max_entries if
the map is not loaded yet.

So the new steps are:
* bpf_object__open_buffer() to open Elf file from a buffer;
* bpf_object__find_map_by_name() to find relevant map;
* bpf_map__resize() to update max_entries.

That's much simpler and works with BTF.

Signed-off-by: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-02-15 15:20:42 +01:00
..
api perf tools: Fix tracing_path_mount proper path 2018-10-16 12:27:46 -03:00
bpf libbpf: Introduce bpf_map__resize 2019-02-15 15:20:42 +01:00
lockdep tools/lib/lockdep/tests: Test the lockdep_reset_lock() implementation 2018-12-11 14:54:51 +01:00
subcmd tools lib subcmd: Don't add the kernel sources to the include path 2018-12-18 12:23:56 -03:00
symbol tools lib symbols: Introduce kallsyms__is_function() 2018-04-26 13:47:14 -03:00
traceevent tools lib traceevent: Remove tep_data_event_from_type() API 2019-01-08 13:28:13 -03:00
bitmap.c
find_bit.c
hweight.c
rbtree.c
str_error_r.c objtool, perf: Fix GCC 8 -Wrestrict error 2018-03-19 13:51:54 -03:00
string.c
vsprintf.c