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Eduard Zingerman says: ==================== veristat: memory accounting for bpf programs When working on the verifier, it is sometimes interesting to know how a particular change affects memory consumption. This patch-set modifies veristat to provide such information. As a collateral, kernel needs an update to make allocations reachable from BPF program load accountable in memcg statistics. Here is a sample output: Program Peak states Peak memory (MiB) --------------- ----------- ----------------- lavd_select_cpu 2153 43 lavd_enqueue 1982 41 lavd_dispatch 3480 28 Technically, this is implemented by creating and entering a new cgroup at the start of veristat execution. The difference between values from cgroup "memory.peak" file before and after bpf_object__load() is used as a metric. To minimize measurements jitter data is collected in megabytes. Changelog: v2: https://lore.kernel.org/bpf/20250612130835.2478649-1-eddyz87@gmail.com/ v2 -> v3: - bpf_verifier_state->jmp_history and bpf_verifier_env->explored_states allocations are switched from GFP_USER to GFP_KERNEL_ACCOUNT (Andrii, Alexei); - veristat.c:STR macro removed, PATH_MAX-1 == 4095 is hard-coded in scanf format strings (Andrii); - env->{orig,stat}_cgroup size changed to PATH_MAX (Andrii); - snprintf_trunc() is removed, flag -Wno-format-truncation is added to CFLAGS for veristat.o when compiled with gcc; v1: https://lore.kernel.org/bpf/20250605230609.1444980-1-eddyz87@gmail.com/ v1 -> v2: - a single cgroup, created at the beginning of execution, is now used for measurements (Andrii, Mykyta); - cgroup namespace is not created, as it turned out to be useless (Andrii); - veristat no longer mounts cgroup fs or changes subtree_control, instead it looks for an existing mount point and reports an error if memory.peak file can't be opened (Andrii, Alexei); - if 'mem_peak' statistics is not enabled, veristat skips cgroup setup; - code sharing with cgroup_helpers.c was considered but was decided against to simplify veristat github sync. ==================== Link: https://patch.msgid.link/20250613072147.3938139-1-eddyz87@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 reStructuredText 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.