// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_core_read.h>
#include "cgroup_iter_memcg.h"

char _license[] SEC("license") = "GPL";

/* The latest values read are stored here. */
struct memcg_query memcg_query SEC(".data.query");

SEC("iter.s/cgroup")
int cgroup_memcg_query(struct bpf_iter__cgroup *ctx)
{
        struct cgroup *cgrp = ctx->cgroup;
        struct cgroup_subsys_state *css;
        struct mem_cgroup *memcg;

        if (!cgrp)
                return 1;

        css = &cgrp->self;
        memcg = bpf_get_mem_cgroup(css);
        if (!memcg)
                return 1;

        bpf_mem_cgroup_flush_stats(memcg);

        memcg_query.nr_anon_mapped = bpf_mem_cgroup_page_state(
                memcg,
                bpf_core_enum_value(enum node_stat_item, NR_ANON_MAPPED));
        memcg_query.nr_shmem = bpf_mem_cgroup_page_state(
                memcg, bpf_core_enum_value(enum node_stat_item, NR_SHMEM));
        memcg_query.nr_file_pages = bpf_mem_cgroup_page_state(
                memcg, bpf_core_enum_value(enum node_stat_item, NR_FILE_PAGES));
        memcg_query.nr_file_mapped = bpf_mem_cgroup_page_state(
                memcg,
                bpf_core_enum_value(enum node_stat_item, NR_FILE_MAPPED));
        memcg_query.pgfault = bpf_mem_cgroup_vm_events(
                memcg, bpf_core_enum_value(enum vm_event_item, PGFAULT));

        bpf_put_mem_cgroup(memcg);

        return 0;
}