mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-04-06 21:57:16 -04:00
67cdcc405b
This commit adds a new field mem_peak / "Peak memory (MiB)" field to a
set of gathered statistics. The field is intended as an estimate for
peak verifier memory consumption for processing of a given program.
Mechanically stat is collected as follows:
- At the beginning of handle_verif_mode() a new cgroup is created
and veristat process is moved into this cgroup.
- At each program load:
- bpf_object__load() is split into bpf_object__prepare() and
bpf_object__load() to avoid accounting for memory allocated for
maps;
- before bpf_object__load():
- a write to "memory.peak" file of the new cgroup is used to reset
cgroup statistics;
- updated value is read from "memory.peak" file and stashed;
- after bpf_object__load() "memory.peak" is read again and
difference between new and stashed values is used as a metric.
If any of the above steps fails veristat proceeds w/o collecting
mem_peak information for a program, reporting mem_peak as -1.
While memcg provides data in bytes (converted from pages), veristat
converts it to megabytes to avoid jitter when comparing results of
different executions.
The change has no measurable impact on veristat running time.
A correlation between "Peak states" and "Peak memory" fields provides
a sanity check for gathered statistics, e.g. a sample of data for
sched_ext programs:
Program Peak states Peak memory (MiB)
------------------------ ----------- -----------------
lavd_select_cpu 2153 44
lavd_enqueue 1982 41
lavd_dispatch 3480 28
layered_dispatch 1417 17
layered_enqueue 760 11
lavd_cpu_offline 349 6
lavd_cpu_online 349 6
lavd_init 394 6
rusty_init 350 5
layered_select_cpu 391 4
...
rusty_stopping 134 1
arena_topology_node_init 170 0
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250613072147.3938139-3-eddyz87@gmail.com