diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c
index bed1661596f7..12a6d4ddbd77 100644
--- a/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c
+++ b/tools/testing/selftests/bpf/prog_tests/cgroup_hierarchical_stats.c
@@ -1,6 +1,9 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Functions to manage eBPF programs attached to cgroup subsystems
+ * This test runs a BPF program that keeps a stat of the number of processes
+ * that ever attached to a cgroup, and makes sure that BPF integrates well with
+ * the rstat framework to efficiently collect those stat percpu to avoid
+ * locking, and to efficiently aggregate the stat across the hierarchy.
  *
  * Copyright 2022 Google LLC.
  */
@@ -21,8 +24,10 @@
 #define PAGE_SIZE 4096
 #define MB(x) (x << 20)
 
+#define PROCESSES_PER_CGROUP 3
+
 #define BPFFS_ROOT "/sys/fs/bpf/"
-#define BPFFS_VMSCAN BPFFS_ROOT"vmscan/"
+#define BPFFS_ATTACH_COUNTERS BPFFS_ROOT"attach_counters/"
 
 #define CG_ROOT_NAME "root"
 #define CG_ROOT_ID 1
@@ -79,7 +84,7 @@ static int setup_bpffs(void)
 		return err;
 
 	/* Create a directory to contain stat files in bpffs */
-	err = mkdir(BPFFS_VMSCAN, 0755);
+	err = mkdir(BPFFS_ATTACH_COUNTERS, 0755);
 	if (!ASSERT_OK(err, "mkdir"))
 		return err;
 
@@ -89,7 +94,7 @@ static int setup_bpffs(void)
 static void cleanup_bpffs(void)
 {
 	/* Remove created directory in bpffs */
-	ASSERT_OK(rmdir(BPFFS_VMSCAN), "rmdir "BPFFS_VMSCAN);
+	ASSERT_OK(rmdir(BPFFS_ATTACH_COUNTERS), "rmdir "BPFFS_ATTACH_COUNTERS);
 
 	/* Unmount bpffs, if it wasn't already mounted when we started */
 	if (mounted_bpffs)
@@ -118,18 +123,6 @@ static int setup_cgroups(void)
 
 		cgroups[i].fd = fd;
 		cgroups[i].id = get_cgroup_id(cgroups[i].path);
-
-		/*
-		 * Enable memcg controller for the entire hierarchy.
-		 * Note that stats are collected for all cgroups in a hierarchy
-		 * with memcg enabled anyway, but are only exposed for cgroups
-		 * that have memcg enabled.
-		 */
-		if (i < N_NON_LEAF_CGROUPS) {
-			err = enable_controllers(cgroups[i].path, "memory");
-			if (!ASSERT_OK(err, "enable_controllers"))
-				return err;
-		}
 	}
 	return 0;
 }
@@ -154,109 +147,85 @@ static void destroy_hierarchy(void)
 	cleanup_bpffs();
 }
 
-static int reclaimer(const char *cgroup_path, size_t size)
+static int attach_processes(void)
 {
-	static char size_buf[128];
-	char *buf, *ptr;
-	int err;
-
-	/* Join cgroup in the parent process workdir */
-	if (join_parent_cgroup(cgroup_path))
-		return EACCES;
-
-	/* Allocate memory */
-	buf = malloc(size);
-	if (!buf)
-		return ENOMEM;
+	int i, j, status;
 
-	/* Write to memory to make sure it's actually allocated */
-	for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
-		*ptr = 1;
-
-	/* Try to reclaim memory */
-	snprintf(size_buf, 128, "%lu", size);
-	err = write_cgroup_file_parent(cgroup_path, "memory.reclaim", size_buf);
-
-	free(buf);
-	/* memory.reclaim returns EAGAIN if the amount is not fully reclaimed */
-	if (err && errno != EAGAIN)
-		return errno;
-
-	return 0;
-}
-
-static int induce_vmscan(void)
-{
-	int i, status;
-
-	/*
-	 * In every leaf cgroup, run a child process that allocates some memory
-	 * and attempts to reclaim some of it.
-	 */
+	/* In every leaf cgroup, attach 3 processes */
 	for (i = N_NON_LEAF_CGROUPS; i < N_CGROUPS; i++) {
-		pid_t pid;
-
-		/* Create reclaimer child */
-		pid = fork();
-		if (pid == 0) {
-			status = reclaimer(cgroups[i].path, MB(5));
-			exit(status);
+		for (j = 0; j < PROCESSES_PER_CGROUP; j++) {
+			pid_t pid;
+
+			/* Create child and attach to cgroup */
+			pid = fork();
+			if (pid == 0) {
+				if (join_parent_cgroup(cgroups[i].path))
+					exit(EACCES);
+				exit(0);
+			}
+
+			/* Cleanup child */
+			waitpid(pid, &status, 0);
+			if (!ASSERT_TRUE(WIFEXITED(status), "child process exited"))
+				return 1;
+			if (!ASSERT_EQ(WEXITSTATUS(status), 0,
+				       "child process exit code"))
+				return 1;
 		}
-
-		/* Cleanup reclaimer child */
-		waitpid(pid, &status, 0);
-		ASSERT_TRUE(WIFEXITED(status), "reclaimer exited");
-		ASSERT_EQ(WEXITSTATUS(status), 0, "reclaim exit code");
 	}
 	return 0;
 }
 
 static unsigned long long
-get_cgroup_vmscan_delay(unsigned long long cgroup_id, const char *file_name)
+get_attach_counter(unsigned long long cgroup_id, const char *file_name)
 {
-	unsigned long long vmscan = 0, id = 0;
+	unsigned long long attach_counter = 0, id = 0;
 	static char buf[128], path[128];
 
 	/* For every cgroup, read the file generated by cgroup_iter */
-	snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name);
+	snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, file_name);
 	if (!ASSERT_OK(read_from_file(path, buf, 128), "read cgroup_iter"))
 		return 0;
 
 	/* Check the output file formatting */
-	ASSERT_EQ(sscanf(buf, "cg_id: %llu, total_vmscan_delay: %llu\n",
-			 &id, &vmscan), 2, "output format");
+	ASSERT_EQ(sscanf(buf, "cg_id: %llu, attach_counter: %llu\n",
+			 &id, &attach_counter), 2, "output format");
 
 	/* Check that the cgroup_id is displayed correctly */
 	ASSERT_EQ(id, cgroup_id, "cgroup_id");
-	/* Check that the vmscan reading is non-zero */
-	ASSERT_GT(vmscan, 0, "vmscan_reading");
-	return vmscan;
+	/* Check that the counter is non-zero */
+	ASSERT_GT(attach_counter, 0, "attach counter non-zero");
+	return attach_counter;
 }
 
-static void check_vmscan_stats(void)
+static void check_attach_counters(void)
 {
-	unsigned long long vmscan_readings[N_CGROUPS], vmscan_root;
+	unsigned long long attach_counters[N_CGROUPS], root_attach_counter;
 	int i;
 
-	for (i = 0; i < N_CGROUPS; i++) {
-		vmscan_readings[i] = get_cgroup_vmscan_delay(cgroups[i].id,
-							     cgroups[i].name);
-	}
+	for (i = 0; i < N_CGROUPS; i++)
+		attach_counters[i] = get_attach_counter(cgroups[i].id,
+							cgroups[i].name);
 
 	/* Read stats for root too */
-	vmscan_root = get_cgroup_vmscan_delay(CG_ROOT_ID, CG_ROOT_NAME);
+	root_attach_counter = get_attach_counter(CG_ROOT_ID, CG_ROOT_NAME);
+
+	/* Check that all leafs cgroups have an attach counter of 3 */
+	for (i = N_NON_LEAF_CGROUPS; i < N_CGROUPS; i++)
+		ASSERT_EQ(attach_counters[i], PROCESSES_PER_CGROUP,
+			  "leaf cgroup attach counter");
 
 	/* Check that child1 == child1_1 + child1_2 */
-	ASSERT_EQ(vmscan_readings[1], vmscan_readings[3] + vmscan_readings[4],
-		  "child1_vmscan");
+	ASSERT_EQ(attach_counters[1], attach_counters[3] + attach_counters[4],
+		  "child1_counter");
 	/* Check that child2 == child2_1 + child2_2 */
-	ASSERT_EQ(vmscan_readings[2], vmscan_readings[5] + vmscan_readings[6],
-		  "child2_vmscan");
+	ASSERT_EQ(attach_counters[2], attach_counters[5] + attach_counters[6],
+		  "child2_counter");
 	/* Check that test == child1 + child2 */
-	ASSERT_EQ(vmscan_readings[0], vmscan_readings[1] + vmscan_readings[2],
-		  "test_vmscan");
+	ASSERT_EQ(attach_counters[0], attach_counters[1] + attach_counters[2],
+		  "test_counter");
 	/* Check that root >= test */
-	ASSERT_GE(vmscan_root, vmscan_readings[1], "root_vmscan");
+	ASSERT_GE(root_attach_counter, attach_counters[1], "root_counter");
 }
 
 /* Creates iter link and pins in bpffs, returns 0 on success, -errno on failure.
@@ -278,12 +247,12 @@ static int setup_cgroup_iter(struct cgroup_hierarchical_stats *obj,
 	linfo.cgroup.order = BPF_CGROUP_ITER_SELF_ONLY;
 	opts.link_info = &linfo;
 	opts.link_info_len = sizeof(linfo);
-	link = bpf_program__attach_iter(obj->progs.dump_vmscan, &opts);
+	link = bpf_program__attach_iter(obj->progs.dumper, &opts);
 	if (!ASSERT_OK_PTR(link, "attach_iter"))
 		return -EFAULT;
 
 	/* Pin the link to a bpffs file */
-	snprintf(path, 128, "%s%s", BPFFS_VMSCAN, file_name);
+	snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, file_name);
 	err = bpf_link__pin(link, path);
 	ASSERT_OK(err, "pin cgroup_iter");
 
@@ -313,7 +282,7 @@ static int setup_progs(struct cgroup_hierarchical_stats **skel)
 	if (!ASSERT_OK(err, "setup_cgroup_iter"))
 		return err;
 
-	bpf_program__set_autoattach((*skel)->progs.dump_vmscan, false);
+	bpf_program__set_autoattach((*skel)->progs.dumper, false);
 	err = cgroup_hierarchical_stats__attach(*skel);
 	if (!ASSERT_OK(err, "attach"))
 		return err;
@@ -328,13 +297,13 @@ static void destroy_progs(struct cgroup_hierarchical_stats *skel)
 
 	for (i = 0; i < N_CGROUPS; i++) {
 		/* Delete files in bpffs that cgroup_iters are pinned in */
-		snprintf(path, 128, "%s%s", BPFFS_VMSCAN,
+		snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS,
 			 cgroups[i].name);
 		ASSERT_OK(remove(path), "remove cgroup_iter pin");
 	}
 
 	/* Delete root file in bpffs */
-	snprintf(path, 128, "%s%s", BPFFS_VMSCAN, CG_ROOT_NAME);
+	snprintf(path, 128, "%s%s", BPFFS_ATTACH_COUNTERS, CG_ROOT_NAME);
 	ASSERT_OK(remove(path), "remove cgroup_iter root pin");
 	cgroup_hierarchical_stats__destroy(skel);
 }
@@ -347,9 +316,9 @@ void test_cgroup_hierarchical_stats(void)
 		goto hierarchy_cleanup;
 	if (setup_progs(&skel))
 		goto cleanup;
-	if (induce_vmscan())
+	if (attach_processes())
 		goto cleanup;
-	check_vmscan_stats();
+	check_attach_counters();
 cleanup:
 	destroy_progs(skel);
 hierarchy_cleanup:
diff --git a/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c b/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c
index 8ab4253a1592..c74362854948 100644
--- a/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c
+++ b/tools/testing/selftests/bpf/progs/cgroup_hierarchical_stats.c
@@ -1,7 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * Functions to manage eBPF programs attached to cgroup subsystems
- *
  * Copyright 2022 Google LLC.
  */
 #include "vmlinux.h"
@@ -11,25 +9,14 @@
 
 char _license[] SEC("license") = "GPL";
 
-/*
- * Start times are stored per-task, not per-cgroup, as multiple tasks in one
- * cgroup can perform reclaim concurrently.
- */
-struct {
-	__uint(type, BPF_MAP_TYPE_TASK_STORAGE);
-	__uint(map_flags, BPF_F_NO_PREALLOC);
-	__type(key, int);
-	__type(value, __u64);
-} vmscan_start_time SEC(".maps");
-
-struct vmscan_percpu {
+struct percpu_attach_counter {
 	/* Previous percpu state, to figure out if we have new updates */
 	__u64 prev;
 	/* Current percpu state */
 	__u64 state;
 };
 
-struct vmscan {
+struct attach_counter {
 	/* State propagated through children, pending aggregation */
 	__u64 pending;
 	/* Total state, including all cpus and all children */
@@ -38,147 +25,94 @@ struct vmscan {
 
 struct {
 	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
-	__uint(max_entries, 100);
+	__uint(max_entries, 1024);
 	__type(key, __u64);
-	__type(value, struct vmscan_percpu);
-} pcpu_cgroup_vmscan_elapsed SEC(".maps");
+	__type(value, struct percpu_attach_counter);
+} percpu_attach_counters SEC(".maps");
 
 struct {
 	__uint(type, BPF_MAP_TYPE_HASH);
-	__uint(max_entries, 100);
+	__uint(max_entries, 1024);
 	__type(key, __u64);
-	__type(value, struct vmscan);
-} cgroup_vmscan_elapsed SEC(".maps");
+	__type(value, struct attach_counter);
+} attach_counters SEC(".maps");
 
 extern void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) __ksym;
 extern void cgroup_rstat_flush(struct cgroup *cgrp) __ksym;
 
-static struct cgroup *task_memcg(struct task_struct *task)
-{
-	int cgrp_id;
-
-#if __has_builtin(__builtin_preserve_enum_value)
-	cgrp_id = bpf_core_enum_value(enum cgroup_subsys_id, memory_cgrp_id);
-#else
-	cgrp_id = memory_cgrp_id;
-#endif
-	return task->cgroups->subsys[cgrp_id]->cgroup;
-}
-
 static uint64_t cgroup_id(struct cgroup *cgrp)
 {
 	return cgrp->kn->id;
 }
 
-static int create_vmscan_percpu_elem(__u64 cg_id, __u64 state)
+static int create_percpu_attach_counter(__u64 cg_id, __u64 state)
 {
-	struct vmscan_percpu pcpu_init = {.state = state, .prev = 0};
+	struct percpu_attach_counter pcpu_init = {.state = state, .prev = 0};
 
-	return bpf_map_update_elem(&pcpu_cgroup_vmscan_elapsed, &cg_id,
+	return bpf_map_update_elem(&percpu_attach_counters, &cg_id,
 				   &pcpu_init, BPF_NOEXIST);
 }
 
-static int create_vmscan_elem(__u64 cg_id, __u64 state, __u64 pending)
+static int create_attach_counter(__u64 cg_id, __u64 state, __u64 pending)
 {
-	struct vmscan init = {.state = state, .pending = pending};
+	struct attach_counter init = {.state = state, .pending = pending};
 
-	return bpf_map_update_elem(&cgroup_vmscan_elapsed, &cg_id,
+	return bpf_map_update_elem(&attach_counters, &cg_id,
 				   &init, BPF_NOEXIST);
 }
 
-SEC("tp_btf/mm_vmscan_memcg_reclaim_begin")
-int BPF_PROG(vmscan_start, int order, gfp_t gfp_flags)
+SEC("fentry/cgroup_attach_task")
+int BPF_PROG(counter, struct cgroup *dst_cgrp, struct task_struct *leader,
+	     bool threadgroup)
 {
-	struct task_struct *task = bpf_get_current_task_btf();
-	__u64 *start_time_ptr;
-
-	start_time_ptr = bpf_task_storage_get(&vmscan_start_time, task, 0,
-					      BPF_LOCAL_STORAGE_GET_F_CREATE);
-	if (start_time_ptr)
-		*start_time_ptr = bpf_ktime_get_ns();
-	return 0;
-}
-
-SEC("tp_btf/mm_vmscan_memcg_reclaim_end")
-int BPF_PROG(vmscan_end, unsigned long nr_reclaimed)
-{
-	struct vmscan_percpu *pcpu_stat;
-	struct task_struct *current = bpf_get_current_task_btf();
-	struct cgroup *cgrp;
-	__u64 *start_time_ptr;
-	__u64 current_elapsed, cg_id;
-	__u64 end_time = bpf_ktime_get_ns();
-
-	/*
-	 * cgrp is the first parent cgroup of current that has memcg enabled in
-	 * its subtree_control, or NULL if memcg is disabled in the entire tree.
-	 * In a cgroup hierarchy like this:
-	 *                               a
-	 *                              / \
-	 *                             b   c
-	 *  If "a" has memcg enabled, while "b" doesn't, then processes in "b"
-	 *  will accumulate their stats directly to "a". This makes sure that no
-	 *  stats are lost from processes in leaf cgroups that don't have memcg
-	 *  enabled, but only exposes stats for cgroups that have memcg enabled.
-	 */
-	cgrp = task_memcg(current);
-	if (!cgrp)
+	__u64 cg_id = cgroup_id(dst_cgrp);
+	struct percpu_attach_counter *pcpu_counter = bpf_map_lookup_elem(
+			&percpu_attach_counters,
+			&cg_id);
+
+	if (pcpu_counter)
+		pcpu_counter->state += 1;
+	else if (create_percpu_attach_counter(cg_id, 1))
 		return 0;
 
-	cg_id = cgroup_id(cgrp);
-	start_time_ptr = bpf_task_storage_get(&vmscan_start_time, current, 0,
-					      BPF_LOCAL_STORAGE_GET_F_CREATE);
-	if (!start_time_ptr)
-		return 0;
-
-	current_elapsed = end_time - *start_time_ptr;
-	pcpu_stat = bpf_map_lookup_elem(&pcpu_cgroup_vmscan_elapsed,
-					&cg_id);
-	if (pcpu_stat)
-		pcpu_stat->state += current_elapsed;
-	else if (create_vmscan_percpu_elem(cg_id, current_elapsed))
-		return 0;
-
-	cgroup_rstat_updated(cgrp, bpf_get_smp_processor_id());
+	cgroup_rstat_updated(dst_cgrp, bpf_get_smp_processor_id());
 	return 0;
 }
 
 SEC("fentry/bpf_rstat_flush")
-int BPF_PROG(vmscan_flush, struct cgroup *cgrp, struct cgroup *parent, int cpu)
+int BPF_PROG(flusher, struct cgroup *cgrp, struct cgroup *parent, int cpu)
 {
-	struct vmscan_percpu *pcpu_stat;
-	struct vmscan *total_stat, *parent_stat;
+	struct percpu_attach_counter *pcpu_counter;
+	struct attach_counter *total_counter, *parent_counter;
 	__u64 cg_id = cgroup_id(cgrp);
 	__u64 parent_cg_id = parent ? cgroup_id(parent) : 0;
-	__u64 *pcpu_vmscan;
 	__u64 state;
 	__u64 delta = 0;
 
 	/* Add CPU changes on this level since the last flush */
-	pcpu_stat = bpf_map_lookup_percpu_elem(&pcpu_cgroup_vmscan_elapsed,
-					       &cg_id, cpu);
-	if (pcpu_stat) {
-		state = pcpu_stat->state;
-		delta += state - pcpu_stat->prev;
-		pcpu_stat->prev = state;
+	pcpu_counter = bpf_map_lookup_percpu_elem(&percpu_attach_counters,
+						  &cg_id, cpu);
+	if (pcpu_counter) {
+		state = pcpu_counter->state;
+		delta += state - pcpu_counter->prev;
+		pcpu_counter->prev = state;
 	}
 
-	total_stat = bpf_map_lookup_elem(&cgroup_vmscan_elapsed, &cg_id);
-	if (!total_stat) {
-		if (create_vmscan_elem(cg_id, delta, 0))
+	total_counter = bpf_map_lookup_elem(&attach_counters, &cg_id);
+	if (!total_counter) {
+		if (create_attach_counter(cg_id, delta, 0))
 			return 0;
-
 		goto update_parent;
 	}
 
 	/* Collect pending stats from subtree */
-	if (total_stat->pending) {
-		delta += total_stat->pending;
-		total_stat->pending = 0;
+	if (total_counter->pending) {
+		delta += total_counter->pending;
+		total_counter->pending = 0;
 	}
 
 	/* Propagate changes to this cgroup's total */
-	total_stat->state += delta;
+	total_counter->state += delta;
 
 update_parent:
 	/* Skip if there are no changes to propagate, or no parent */
@@ -186,20 +120,20 @@ int BPF_PROG(vmscan_flush, struct cgroup *cgrp, struct cgroup *parent, int cpu)
 		return 0;
 
 	/* Propagate changes to cgroup's parent */
-	parent_stat = bpf_map_lookup_elem(&cgroup_vmscan_elapsed,
-					  &parent_cg_id);
-	if (parent_stat)
-		parent_stat->pending += delta;
+	parent_counter = bpf_map_lookup_elem(&attach_counters,
+					     &parent_cg_id);
+	if (parent_counter)
+		parent_counter->pending += delta;
 	else
-		create_vmscan_elem(parent_cg_id, 0, delta);
+		create_attach_counter(parent_cg_id, 0, delta);
 	return 0;
 }
 
 SEC("iter.s/cgroup")
-int BPF_PROG(dump_vmscan, struct bpf_iter_meta *meta, struct cgroup *cgrp)
+int BPF_PROG(dumper, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 {
 	struct seq_file *seq = meta->seq;
-	struct vmscan *total_stat;
+	struct attach_counter *total_counter;
 	__u64 cg_id = cgrp ? cgroup_id(cgrp) : 0;
 
 	/* Do nothing for the terminal call */
@@ -209,18 +143,13 @@ int BPF_PROG(dump_vmscan, struct bpf_iter_meta *meta, struct cgroup *cgrp)
 	/* Flush the stats to make sure we get the most updated numbers */
 	cgroup_rstat_flush(cgrp);
 
-	total_stat = bpf_map_lookup_elem(&cgroup_vmscan_elapsed, &cg_id);
-	if (!total_stat) {
-		BPF_SEQ_PRINTF(seq, "cg_id: %llu, total_vmscan_delay: 0\n",
+	total_counter = bpf_map_lookup_elem(&attach_counters, &cg_id);
+	if (!total_counter) {
+		BPF_SEQ_PRINTF(seq, "cg_id: %llu, attach_counter: 0\n",
 			       cg_id);
 	} else {
-		BPF_SEQ_PRINTF(seq, "cg_id: %llu, total_vmscan_delay: %llu\n",
-			       cg_id, total_stat->state);
+		BPF_SEQ_PRINTF(seq, "cg_id: %llu, attach_counter: %llu\n",
+			       cg_id, total_counter->state);
 	}
-
-	/*
-	 * We only dump stats for one cgroup here, so return 1 to stop
-	 * iteration after the first cgroup.
-	 */
-	return 1;
+	return 0;
 }
