summaryrefslogtreecommitdiffstats
path: root/collectors/ebpf.plugin/ebpf_oomkill.c
blob: d93e4159eeb59c37bed42006b35e934cd2db905d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
// SPDX-License-Identifier: GPL-3.0-or-later

#include "ebpf.h"
#include "ebpf_oomkill.h"

struct config oomkill_config = { .first_section = NULL,
    .last_section = NULL,
    .mutex = NETDATA_MUTEX_INITIALIZER,
    .index = { .avl_tree = { .root = NULL, .compar = appconfig_section_compare },
        .rwlock = AVL_LOCK_INITIALIZER } };

#define OOMKILL_MAP_KILLCNT 0
static ebpf_local_maps_t oomkill_maps[] = {
    {
        .name = "tbl_oomkill",
        .internal_input = NETDATA_OOMKILL_MAX_ENTRIES,
        .user_input = 0,
        .type = NETDATA_EBPF_MAP_STATIC,
        .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED
    },
    /* end */
    {
        .name = NULL,
        .internal_input = 0,
        .user_input = 0,
        .type = NETDATA_EBPF_MAP_CONTROLLER,
        .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED
    }
};

static ebpf_tracepoint_t oomkill_tracepoints[] = {
    {.enabled = false, .class = "oom", .event = "mark_victim"},
    /* end */
    {.enabled = false, .class = NULL, .event = NULL}
};

static netdata_publish_syscall_t oomkill_publish_aggregated = {.name = "oomkill", .dimension = "oomkill",
                                                               .algorithm = "absolute",
                                                               .next = NULL};

/**
 * Clean up the main thread.
 *
 * @param ptr thread data.
 */
static void oomkill_cleanup(void *ptr)
{
    ebpf_module_t *em = (ebpf_module_t *)ptr;
    em->thread->enabled = NETDATA_THREAD_EBPF_STOPPED;
}

static void oomkill_write_data(int32_t *keys, uint32_t total)
{
    // for each app, see if it was OOM killed. record as 1 if so otherwise 0.
    struct target *w;
    for (w = apps_groups_root_target; w != NULL; w = w->next) {
        if (likely(w->exposed && w->processes)) {
            bool was_oomkilled = false;
            struct pid_on_target *pids = w->root_pid;
            while (pids) {
                uint32_t j;
                for (j = 0; j < total; j++) {
                    if (pids->pid == keys[j]) {
                        was_oomkilled = true;
                        // set to 0 so we consider it "done".
                        keys[j] = 0;
                        goto write_dim;
                    }
                }
                pids = pids->next;
            }

        write_dim:;
            write_chart_dimension(w->name, was_oomkilled);
        }
    }

    // for any remaining keys for which we couldn't find a group, this could be
    // for various reasons, but the primary one is that the PID has not yet
    // been picked up by the process thread when parsing the proc filesystem.
    // since it's been OOM killed, it will never be parsed in the future, so
    // we have no choice but to dump it into `other`.
    uint32_t j;
    uint32_t rem_count = 0;
    for (j = 0; j < total; j++) {
        int32_t key = keys[j];
        if (key != 0) {
            rem_count += 1;
        }
    }
    if (rem_count > 0) {
        write_chart_dimension("other", rem_count);
    }
}

/**
 * Create specific OOMkill charts
 *
 * Create charts for cgroup/application.
 *
 * @param type the chart type.
 * @param update_every value to overwrite the update frequency set by the server.
 */
static void ebpf_create_specific_oomkill_charts(char *type, int update_every)
{
    ebpf_create_chart(type, NETDATA_OOMKILL_CHART, "OOM kills. This chart is provided by eBPF plugin.",
                      EBPF_COMMON_DIMENSION_KILLS, NETDATA_EBPF_MEMORY_GROUP,
                      NETDATA_CGROUP_OOMKILLS_CONTEXT, NETDATA_EBPF_CHART_TYPE_LINE,
                      NETDATA_CHART_PRIO_CGROUPS_CONTAINERS + 5600,
                      ebpf_create_global_dimension,
                      &oomkill_publish_aggregated, 1, update_every, NETDATA_EBPF_MODULE_NAME_OOMKILL);
}

/**
 *  Create Systemd OOMkill Charts
 *
 *  Create charts when systemd is enabled
 *
 *  @param update_every value to overwrite the update frequency set by the server.
 **/
static void ebpf_create_systemd_oomkill_charts(int update_every)
{
    ebpf_create_charts_on_systemd(NETDATA_OOMKILL_CHART, "OOM kills. This chart is provided by eBPF plugin.",
                                  EBPF_COMMON_DIMENSION_KILLS, NETDATA_EBPF_MEMORY_GROUP,
                                  NETDATA_EBPF_CHART_TYPE_LINE, 20191,
                                  ebpf_algorithms[NETDATA_EBPF_INCREMENTAL_IDX], NULL,
                                  NETDATA_EBPF_MODULE_NAME_OOMKILL, update_every);
}

/**
 * Send Systemd charts
 *
 * Send collected data to Netdata.
 */
static void ebpf_send_systemd_oomkill_charts()
{
    ebpf_cgroup_target_t *ect;
    write_begin_chart(NETDATA_SERVICE_FAMILY, NETDATA_OOMKILL_CHART);
    for (ect = ebpf_cgroup_pids; ect ; ect = ect->next) {
        if (unlikely(ect->systemd) && unlikely(ect->updated)) {
            write_chart_dimension(ect->name, (long long) ect->oomkill);
            ect->oomkill = 0;
        }
    }
    write_end_chart();
}

/*
 * Send Specific OOMkill data
 *
 * Send data for specific cgroup/apps.
 *
 * @param type   chart type
 * @param value  value for oomkill
 */
static void ebpf_send_specific_oomkill_data(char *type, int value)
{
    write_begin_chart(type, NETDATA_OOMKILL_CHART);
    write_chart_dimension(oomkill_publish_aggregated.name, (long long)value);
    write_end_chart();
}

/**
 * Create specific OOMkill charts
 *
 * Create charts for cgroup/application.
 *
 * @param type the chart type.
 * @param update_every value to overwrite the update frequency set by the server.
 */
static void ebpf_obsolete_specific_oomkill_charts(char *type, int update_every)
{
    ebpf_write_chart_obsolete(type, NETDATA_OOMKILL_CHART, "OOM kills. This chart is provided by eBPF plugin.",
                              EBPF_COMMON_DIMENSION_KILLS, NETDATA_EBPF_MEMORY_GROUP,
                              NETDATA_EBPF_CHART_TYPE_LINE, NETDATA_CGROUP_OOMKILLS_CONTEXT,
                              NETDATA_CHART_PRIO_CGROUPS_CONTAINERS + 5600, update_every);
}

/**
 * Send data to Netdata calling auxiliary functions.
 *
 * @param update_every value to overwrite the update frequency set by the server.
*/
void ebpf_oomkill_send_cgroup_data(int update_every)
{
    if (!ebpf_cgroup_pids)
        return;

    pthread_mutex_lock(&mutex_cgroup_shm);
    ebpf_cgroup_target_t *ect;

    int has_systemd = shm_ebpf_cgroup.header->systemd_enabled;
    if (has_systemd) {
        if (send_cgroup_chart) {
            ebpf_create_systemd_oomkill_charts(update_every);
        }
        ebpf_send_systemd_oomkill_charts();
    }

    for (ect = ebpf_cgroup_pids; ect ; ect = ect->next) {
        if (ect->systemd)
            continue;

        if (!(ect->flags & NETDATA_EBPF_CGROUP_HAS_OOMKILL_CHART) && ect->updated) {
            ebpf_create_specific_oomkill_charts(ect->name, update_every);
            ect->flags |= NETDATA_EBPF_CGROUP_HAS_OOMKILL_CHART;
        }

        if (ect->flags & NETDATA_EBPF_CGROUP_HAS_OOMKILL_CHART && ect->updated) {
            ebpf_send_specific_oomkill_data(ect->name, ect->oomkill);
        } else {
            ebpf_obsolete_specific_oomkill_charts(ect->name, update_every);
            ect->flags &= ~NETDATA_EBPF_CGROUP_HAS_OOMKILL_CHART;
        }
    }

    pthread_mutex_unlock(&mutex_cgroup_shm);
}

/**
 * Read data
 *
 * Read OOMKILL events from table.
 *
 * @param keys vector where data will be stored
 *
 * @return It returns the number of read elements
 */
static uint32_t oomkill_read_data(int32_t *keys)
{
    // the first `i` entries of `keys` will contain the currently active PIDs
    // in the eBPF map.
    uint32_t i = 0;

    uint32_t curr_key = 0;
    uint32_t key = 0;
    int mapfd = oomkill_maps[OOMKILL_MAP_KILLCNT].map_fd;
    while (bpf_map_get_next_key(mapfd, &curr_key, &key) == 0) {
        curr_key = key;

        keys[i] = (int32_t)key;
        i += 1;

        // delete this key now that we've recorded its existence. there's no
        // race here, as the same PID will only get OOM killed once.
        int test = bpf_map_delete_elem(mapfd, &key);
        if (unlikely(test < 0)) {
            // since there's only 1 thread doing these deletions, it should be
            // impossible to get this condition.
            error("key unexpectedly not available for deletion.");
        }
    }

    return i;
}

/**
 * Update cgroup
 *
 * Update cgroup data based in
 *
 * @param keys  vector with pids that had oomkill event
 * @param total number of elements in keys vector.
 */
static void ebpf_update_oomkill_cgroup(int32_t *keys, uint32_t total)
{
    ebpf_cgroup_target_t *ect;
    for (ect = ebpf_cgroup_pids; ect; ect = ect->next) {
        ect->oomkill = 0;
        struct pid_on_target2 *pids;
        for (pids = ect->pids; pids; pids = pids->next) {
            uint32_t j;
            int32_t pid = pids->pid;
            for (j = 0; j < total; j++) {
                if (pid == keys[j]) {
                    ect->oomkill = 1;
                    break;
                }
            }
        }
    }
}

/**
* Main loop for this collector.
*/
static void oomkill_collector(ebpf_module_t *em)
{
    int cgroups = em->cgroup_charts;
    int update_every = em->update_every;
    int32_t keys[NETDATA_OOMKILL_MAX_ENTRIES];
    memset(keys, 0, sizeof(keys));

    // loop and read until ebpf plugin is closed.
    heartbeat_t hb;
    heartbeat_init(&hb);
    usec_t step = update_every * USEC_PER_SEC;
    while (!ebpf_exit_plugin) {
        (void)heartbeat_next(&hb, step);
        if (ebpf_exit_plugin)
            break;

        pthread_mutex_lock(&collect_data_mutex);
        pthread_mutex_lock(&lock);

        uint32_t count = oomkill_read_data(keys);
        if (cgroups && count)
            ebpf_update_oomkill_cgroup(keys, count);

        // write everything from the ebpf map.
        if (cgroups)
            ebpf_oomkill_send_cgroup_data(update_every);

        if (em->apps_charts & NETDATA_EBPF_APPS_FLAG_CHART_CREATED) {
            write_begin_chart(NETDATA_APPS_FAMILY, NETDATA_OOMKILL_CHART);
            oomkill_write_data(keys, count);
            write_end_chart();
        }

        pthread_mutex_unlock(&lock);
        pthread_mutex_unlock(&collect_data_mutex);
    }
}

/**
 * Create apps charts
 *
 * Call ebpf_create_chart to create the charts on apps submenu.
 *
 * @param em a pointer to the structure with the default values.
 */
void ebpf_oomkill_create_apps_charts(struct ebpf_module *em, void *ptr)
{
    struct target *root = ptr;
    ebpf_create_charts_on_apps(NETDATA_OOMKILL_CHART,
                               "OOM kills",
                               EBPF_COMMON_DIMENSION_KILLS,
                               "mem",
                               NETDATA_EBPF_CHART_TYPE_STACKED,
                               20020,
                               ebpf_algorithms[NETDATA_EBPF_ABSOLUTE_IDX],
                               root, em->update_every, NETDATA_EBPF_MODULE_NAME_OOMKILL);

    em->apps_charts |= NETDATA_EBPF_APPS_FLAG_CHART_CREATED;
}

/**
 * OOM kill tracking thread.
 *
 * @param ptr a `ebpf_module_t *`.
 * @return always NULL.
 */
void *ebpf_oomkill_thread(void *ptr)
{
    netdata_thread_cleanup_push(oomkill_cleanup, ptr);

    ebpf_module_t *em = (ebpf_module_t *)ptr;
    em->maps = oomkill_maps;

#define NETDATA_DEFAULT_OOM_DISABLED_MSG "Disabling OOMKILL thread, because"
    if (unlikely(!all_pids || !em->apps_charts)) {
        // When we are not running integration with apps, we won't fill necessary variables for this thread to run, so
        // we need to disable it.
        if (em->thread->enabled)
            info("%s apps integration is completely disabled.", NETDATA_DEFAULT_OOM_DISABLED_MSG);

        em->thread->enabled = NETDATA_THREAD_EBPF_STOPPED;
    } else if (running_on_kernel < NETDATA_EBPF_KERNEL_4_14) {
        if (em->thread->enabled)
            info("%s kernel does not have necessary tracepoints.", NETDATA_DEFAULT_OOM_DISABLED_MSG);

        em->thread->enabled = NETDATA_THREAD_EBPF_STOPPED;
    }

    if (em->thread->enabled == NETDATA_THREAD_EBPF_STOPPED) {
        goto endoomkill;
    }

    if (ebpf_enable_tracepoints(oomkill_tracepoints) == 0) {
        em->thread->enabled = NETDATA_THREAD_EBPF_STOPPED;
        goto endoomkill;
    }

    em->probe_links = ebpf_load_program(ebpf_plugin_dir, em, running_on_kernel, isrh, &em->objects);
    if (!em->probe_links) {
        em->thread->enabled = NETDATA_THREAD_EBPF_STOPPED;
        goto endoomkill;
    }

    pthread_mutex_lock(&lock);
    ebpf_update_stats(&plugin_statistics, em);
    pthread_mutex_unlock(&lock);

    oomkill_collector(em);

endoomkill:
    ebpf_update_disabled_plugin_stats(em);

    netdata_thread_cleanup_pop(1);

    return NULL;
}