linux-next/samples/damon/wsse.c
SeongJae Park 6c49b56bbc samples/damon/wsse: implement working set size estimation and logging
Implement the DAMON-based working set size estimation logic.  The logic
iterates memory regions in DAMON-generated access pattern snapshot for
every aggregation interval and get the total sum of the size of any region
having one or higher 'nr_accesses' count.  That is, it assumes any region
having one or higher 'nr_accesses' to be a part of the working set.  The
estimated value is reported to the user by printing it to the kernel log.

Link: https://lkml.kernel.org/r/20241210215030.85675-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-12-18 19:51:00 -08:00

117 lines
2.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* working set size estimation: monitor access pattern of given process and
* print estimated working set size (total size of regions that showing some
* access).
*/
#define pr_fmt(fmt) "damon_sample_wsse: " fmt
#include <linux/damon.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
static int target_pid __read_mostly;
module_param(target_pid, int, 0600);
static int damon_sample_wsse_enable_store(
const char *val, const struct kernel_param *kp);
static const struct kernel_param_ops enable_param_ops = {
.set = damon_sample_wsse_enable_store,
.get = param_get_bool,
};
static bool enable __read_mostly;
module_param_cb(enable, &enable_param_ops, &enable, 0600);
MODULE_PARM_DESC(enable, "Enable or disable DAMON_SAMPLE_WSSE");
static struct damon_ctx *ctx;
static struct pid *target_pidp;
static int damon_sample_wsse_after_aggregate(struct damon_ctx *c)
{
struct damon_target *t;
damon_for_each_target(t, c) {
struct damon_region *r;
unsigned long wss = 0;
damon_for_each_region(r, t) {
if (r->nr_accesses > 0)
wss += r->ar.end - r->ar.start;
}
pr_info("wss: %lu\n", wss);
}
return 0;
}
static int damon_sample_wsse_start(void)
{
struct damon_target *target;
pr_info("start\n");
ctx = damon_new_ctx();
if (!ctx)
return -ENOMEM;
if (damon_select_ops(ctx, DAMON_OPS_VADDR)) {
damon_destroy_ctx(ctx);
return -EINVAL;
}
target = damon_new_target();
if (!target) {
damon_destroy_ctx(ctx);
return -ENOMEM;
}
damon_add_target(ctx, target);
target_pidp = find_get_pid(target_pid);
if (!target_pidp) {
damon_destroy_ctx(ctx);
return -EINVAL;
}
target->pid = target_pidp;
ctx->callback.after_aggregation = damon_sample_wsse_after_aggregate;
return damon_start(&ctx, 1, true);
}
static void damon_sample_wsse_stop(void)
{
pr_info("stop\n");
if (ctx) {
damon_stop(&ctx, 1);
damon_destroy_ctx(ctx);
}
if (target_pidp)
put_pid(target_pidp);
}
static int damon_sample_wsse_enable_store(
const char *val, const struct kernel_param *kp)
{
bool enabled = enable;
int err;
err = kstrtobool(val, &enable);
if (err)
return err;
if (enable == enabled)
return 0;
if (enable)
return damon_sample_wsse_start();
damon_sample_wsse_stop();
return 0;
}
static int __init damon_sample_wsse_init(void)
{
return 0;
}
module_init(damon_sample_wsse_init);