1// SPDX-License-Identifier: GPL-2.0
2/*
3 * working set size estimation: monitor access pattern of given process and
4 * print estimated working set size (total size of regions that showing some
5 * access).
6 */
7
8#define pr_fmt(fmt) "damon_sample_wsse: " fmt
9
10#include <linux/damon.h>
11#include <linux/init.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14
15#ifdef MODULE_PARAM_PREFIX
16#undef MODULE_PARAM_PREFIX
17#endif
18#define MODULE_PARAM_PREFIX "damon_sample_wsse."
19
20static int target_pid __read_mostly;
21module_param(target_pid, int, 0600);
22
23static int damon_sample_wsse_enable_store(
24 const char *val, const struct kernel_param *kp);
25
26static const struct kernel_param_ops enabled_param_ops = {
27 .set = damon_sample_wsse_enable_store,
28 .get = param_get_bool,
29};
30
31static bool enabled __read_mostly;
32module_param_cb(enabled, &enabled_param_ops, &enabled, 0600);
33MODULE_PARM_DESC(enabled, "Enable or disable DAMON_SAMPLE_WSSE");
34
35static struct damon_ctx *ctx;
36static struct pid *target_pidp;
37
38static int damon_sample_wsse_repeat_call_fn(void *data)
39{
40 struct damon_ctx *c = data;
41 struct damon_target *t;
42
43 damon_for_each_target(t, c) {
44 struct damon_region *r;
45 unsigned long wss = 0;
46
47 damon_for_each_region(r, t) {
48 if (r->nr_accesses > 0)
49 wss += r->ar.end - r->ar.start;
50 }
51 pr_info("wss: %lu\n", wss);
52 }
53 return 0;
54}
55
56static struct damon_call_control repeat_call_control = {
57 .fn = damon_sample_wsse_repeat_call_fn,
58 .repeat = true,
59};
60
61static int damon_sample_wsse_start(void)
62{
63 struct damon_target *target;
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, id: 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, t: target);
82 target_pidp = find_get_pid(nr: target_pid);
83 if (!target_pidp) {
84 damon_destroy_ctx(ctx);
85 return -EINVAL;
86 }
87 target->pid = target_pidp;
88
89 err = damon_start(ctxs: &ctx, nr_ctxs: 1, exclusive: true);
90 if (err)
91 return err;
92 repeat_call_control.data = ctx;
93 return damon_call(ctx, control: &repeat_call_control);
94}
95
96static void damon_sample_wsse_stop(void)
97{
98 pr_info("stop\n");
99 if (ctx) {
100 damon_stop(ctxs: &ctx, nr_ctxs: 1);
101 damon_destroy_ctx(ctx);
102 }
103}
104
105static int damon_sample_wsse_enable_store(
106 const char *val, const struct kernel_param *kp)
107{
108 bool is_enabled = enabled;
109 int err;
110
111 err = kstrtobool(s: val, res: &enabled);
112 if (err)
113 return err;
114
115 if (enabled == is_enabled)
116 return 0;
117
118 if (!damon_initialized())
119 return 0;
120
121 if (enabled) {
122 err = damon_sample_wsse_start();
123 if (err)
124 enabled = false;
125 return err;
126 }
127 damon_sample_wsse_stop();
128 return 0;
129}
130
131static int __init damon_sample_wsse_init(void)
132{
133 int err = 0;
134
135 if (!damon_initialized()) {
136 err = -ENOMEM;
137 if (enabled)
138 enabled = false;
139 }
140
141 if (enabled) {
142 err = damon_sample_wsse_start();
143 if (err)
144 enabled = false;
145 }
146 return err;
147}
148
149module_init(damon_sample_wsse_init);
150

source code of linux/samples/damon/wsse.c