prcl.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * proactive reclamation: monitor access pattern of a given process, find
  4 * regions that seems not accessed, and proactively page out the regions.
  5 */
  6
  7#define pr_fmt(fmt) "damon_sample_prcl: " fmt
  8
  9#include <linux/damon.h>
 10#include <linux/init.h>
 11#include <linux/kernel.h>
 12#include <linux/module.h>
 13
 14#ifdef MODULE_PARAM_PREFIX
 15#undef MODULE_PARAM_PREFIX
 16#endif
 17#define MODULE_PARAM_PREFIX "damon_sample_prcl."
 18
 19static int target_pid __read_mostly;
 20module_param(target_pid, int, 0600);
 21
 22static int damon_sample_prcl_enable_store(
 23		const char *val, const struct kernel_param *kp);
 24
 25static const struct kernel_param_ops enabled_param_ops = {
 26	.set = damon_sample_prcl_enable_store,
 27	.get = param_get_bool,
 28};
 29
 30static bool enabled __read_mostly;
 31module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
 32MODULE_PARM_DESC(enabled, "Enable or disable DAMON_SAMPLE_PRCL");
 33
 34static struct damon_ctx *ctx;
 35static struct pid *target_pidp;
 36
 37static int damon_sample_prcl_repeat_call_fn(void *data)
 38{
 39	struct damon_ctx *c = data;
 40	struct damon_target *t;
 41
 42	damon_for_each_target(t, c) {
 43		struct damon_region *r;
 44		unsigned long wss = 0;
 45
 46		damon_for_each_region(r, t) {
 47			if (r->nr_accesses > 0)
 48				wss += r->ar.end - r->ar.start;
 49		}
 50		pr_info("wss: %lu\n", wss);
 51	}
 52	return 0;
 53}
 54
 55static struct damon_call_control repeat_call_control = {
 56	.fn = damon_sample_prcl_repeat_call_fn,
 57	.repeat = true,
 58};
 59
 60static int damon_sample_prcl_start(void)
 61{
 62	struct damon_target *target;
 63	struct damos *scheme;
 64	int err;
 65
 66	pr_info("start\n");
 67
 68	ctx = damon_new_ctx();
 69	if (!ctx)
 70		return -ENOMEM;
 71	if (damon_select_ops(ctx, DAMON_OPS_VADDR)) {
 72		damon_destroy_ctx(ctx);
 73		return -EINVAL;
 74	}
 75
 76	target = damon_new_target();
 77	if (!target) {
 78		damon_destroy_ctx(ctx);
 79		return -ENOMEM;
 80	}
 81	damon_add_target(ctx, target);
 82	target_pidp = find_get_pid(target_pid);
 83	if (!target_pidp) {
 84		damon_destroy_ctx(ctx);
 85		return -EINVAL;
 86	}
 87	target->pid = target_pidp;
 88
 89	scheme = damon_new_scheme(
 90			&(struct damos_access_pattern) {
 91			.min_sz_region = PAGE_SIZE,
 92			.max_sz_region = ULONG_MAX,
 93			.min_nr_accesses = 0,
 94			.max_nr_accesses = 0,
 95			.min_age_region = 50,
 96			.max_age_region = UINT_MAX},
 97			DAMOS_PAGEOUT,
 98			0,
 99			&(struct damos_quota){},
100			&(struct damos_watermarks){},
101			NUMA_NO_NODE);
102	if (!scheme) {
103		damon_destroy_ctx(ctx);
104		return -ENOMEM;
105	}
106	damon_set_schemes(ctx, &scheme, 1);
107
108	err = damon_start(&ctx, 1, true);
109	if (err)
110		return err;
111
112	repeat_call_control.data = ctx;
113	return damon_call(ctx, &repeat_call_control);
114}
115
116static void damon_sample_prcl_stop(void)
117{
118	pr_info("stop\n");
119	if (ctx) {
120		damon_stop(&ctx, 1);
121		damon_destroy_ctx(ctx);
122	}
123}
124
125static int damon_sample_prcl_enable_store(
126		const char *val, const struct kernel_param *kp)
127{
128	bool is_enabled = enabled;
129	int err;
130
131	err = kstrtobool(val, &enabled);
132	if (err)
133		return err;
134
135	if (enabled == is_enabled)
136		return 0;
137
138	if (!damon_initialized())
139		return 0;
140
141	if (enabled) {
142		err = damon_sample_prcl_start();
143		if (err)
144			enabled = false;
145		return err;
146	}
147	damon_sample_prcl_stop();
148	return 0;
149}
150
151static int __init damon_sample_prcl_init(void)
152{
153	int err = 0;
154
155	if (!damon_initialized()) {
156		if (enabled)
157			enabled = false;
158		return -ENOMEM;
159	}
160
161	if (enabled) {
162		err = damon_sample_prcl_start();
163		if (err)
164			enabled = false;
165	}
166	return 0;
167}
168
169module_init(damon_sample_prcl_init);