summaryrefslogtreecommitdiffstats
path: root/collectors/ebpf.plugin/ebpf_disk.c
blob: 466c2e3bb47b2f8bce2b468f781e3841df2ad620 (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
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
// SPDX-License-Identifier: GPL-3.0-or-later

#include <sys/resource.h>
#include <stdlib.h>

#include "ebpf.h"
#include "ebpf_disk.h"

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

static ebpf_local_maps_t disk_maps[] = {{.name = "tbl_disk_iocall", .internal_input = NETDATA_DISK_HISTOGRAM_LENGTH,
                                         .user_input = 0, .type = NETDATA_EBPF_MAP_STATIC,
                                         .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED,
#ifdef LIBBPF_MAJOR_VERSION
                                         .map_type = BPF_MAP_TYPE_PERCPU_HASH
#endif
                                        },
                                        {.name = "tmp_disk_tp_stat", .internal_input = 8192, .user_input = 8192,
                                         .type = NETDATA_EBPF_MAP_STATIC,
                                         .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED,
#ifdef LIBBPF_MAJOR_VERSION
                                         .map_type = BPF_MAP_TYPE_PERCPU_HASH
#endif
                                        },
                                        {.name = NULL, .internal_input = 0, .user_input = 0,
                                         .type = NETDATA_EBPF_MAP_CONTROLLER,
                                         .map_fd = ND_EBPF_MAP_FD_NOT_INITIALIZED,
#ifdef LIBBPF_MAJOR_VERSION
                                         .map_type = BPF_MAP_TYPE_PERCPU_ARRAY
#endif
                                         }};
static avl_tree_lock disk_tree;
netdata_ebpf_disks_t *disk_list = NULL;

char *tracepoint_block_type = { "block"} ;
char *tracepoint_block_issue = { "block_rq_issue" };
char *tracepoint_block_rq_complete = { "block_rq_complete" };

static int was_block_issue_enabled = 0;
static int was_block_rq_complete_enabled = 0;

static char **dimensions = NULL;
static netdata_syscall_stat_t disk_aggregated_data[NETDATA_EBPF_HIST_MAX_BINS];
static netdata_publish_syscall_t disk_publish_aggregated[NETDATA_EBPF_HIST_MAX_BINS];

static netdata_idx_t *disk_hash_values = NULL;

ebpf_publish_disk_t *plot_disks = NULL;
pthread_mutex_t plot_mutex;

#ifdef LIBBPF_MAJOR_VERSION
/**
 * Set hash table
 *
 * Set the values for maps according the value given by kernel.
 *
 * @param obj is the main structure for bpf objects.
 */
static inline void ebpf_disk_set_hash_table(struct disk_bpf *obj)
 {
    disk_maps[NETDATA_DISK_IO].map_fd = bpf_map__fd(obj->maps.tbl_disk_iocall);
 }

/**
 * Load and attach
 *
 * Load and attach the eBPF code in kernel.
 *
 * @param obj is the main structure for bpf objects.
 *
 * @return it returns 0 on success and -1 otherwise
 */
static inline int ebpf_disk_load_and_attach(struct disk_bpf *obj)
{
    int ret = disk_bpf__load(obj);
    if (ret) {
        return ret;
    }

    return disk_bpf__attach(obj);
}
#endif

/*****************************************************************
 *
 *  FUNCTIONS TO MANIPULATE HARD DISKS
 *
 *****************************************************************/

/**
 * Parse start
 *
 * Parse start address of disk
 *
 * @param w          structure where data is stored
 * @param filename   variable used to store value
 *
 * @return It returns 0 on success and -1 otherwise
 */
static inline int ebpf_disk_parse_start(netdata_ebpf_disks_t *w, char *filename)
{
    char content[FILENAME_MAX + 1];
    int fd = open(filename, O_RDONLY, 0);
    if (fd < 0) {
        return -1;
    }

    ssize_t file_length = read(fd, content, 4095);
    if (file_length > 0) {
        if (file_length > FILENAME_MAX)
            file_length = FILENAME_MAX;

        content[file_length] = '\0';
        w->start = strtoul(content, NULL, 10);
    }
    close(fd);

    return 0;
}

/**
 * Parse uevent
 *
 * Parse uevent file
 *
 * @param w          structure where data is stored
 * @param filename   variable used to store value
 *
 * @return It returns 0 on success and -1 otherwise
 */
static inline int ebpf_parse_uevent(netdata_ebpf_disks_t *w, char *filename)
{
    char content[FILENAME_MAX + 1];
    int fd = open(filename, O_RDONLY, 0);
    if (fd < 0) {
        return -1;
    }

    ssize_t file_length = read(fd, content, FILENAME_MAX);
    if (file_length > 0) {
        if (file_length > FILENAME_MAX)
            file_length = FILENAME_MAX;

        content[file_length] = '\0';

        char *s = strstr(content, "PARTNAME=EFI");
        if (s) {
            w->main->boot_partition = w;
            w->flags |= NETDATA_DISK_HAS_EFI;
            w->boot_chart = strdupz("disk_bootsector");
        }
    }
    close(fd);

    return 0;
}

/**
 * Parse Size
 *
 * @param w          structure where data is stored
 * @param filename   variable used to store value
 *
 * @return It returns 0 on success and -1 otherwise
 */
static inline int ebpf_parse_size(netdata_ebpf_disks_t *w, char *filename)
{
    char content[FILENAME_MAX + 1];
    int fd = open(filename, O_RDONLY, 0);
    if (fd < 0) {
        return -1;
    }

    ssize_t file_length = read(fd, content, FILENAME_MAX);
    if (file_length > 0) {
        if (file_length > FILENAME_MAX)
            file_length = FILENAME_MAX;

        content[file_length] = '\0';
        w->end = w->start + strtoul(content, NULL, 10) -1;
    }
    close(fd);

    return 0;
}

/**
 * Read Disk information
 *
 * Read disk information from /sys/block
 *
 * @param w    structure where data is stored
 * @param name disk name
 */
static void ebpf_read_disk_info(netdata_ebpf_disks_t *w, char *name)
{
    static netdata_ebpf_disks_t *main_disk = NULL;
    static uint32_t key = 0;
    char *path = { "/sys/block" };
    char disk[NETDATA_DISK_NAME_LEN + 1];
    char filename[FILENAME_MAX + 1];
    snprintfz(disk, NETDATA_DISK_NAME_LEN, "%s", name);
    size_t length = strlen(disk);
    if (!length) {
        return;
    }

    length--;
    size_t curr = length;
    while (isdigit((int)disk[length])) {
        disk[length--] = '\0';
    }

    // We are looking for partition information, if it is a device we will ignore it.
    if (curr == length) {
        main_disk = w;
        key = MKDEV(w->major, w->minor);
        w->bootsector_key = key;
        return;
    }
    w->bootsector_key = key;
    w->main = main_disk;

    snprintfz(filename, FILENAME_MAX, "%s/%s/%s/uevent", path, disk, name);
    if (ebpf_parse_uevent(w, filename))
        return;

    snprintfz(filename, FILENAME_MAX, "%s/%s/%s/start", path, disk, name);
    if (ebpf_disk_parse_start(w, filename))
        return;

    snprintfz(filename, FILENAME_MAX, "%s/%s/%s/size", path, disk, name);
    ebpf_parse_size(w, filename);
}

/**
 * New encode dev
 *
 * New encode algorithm extracted from https://elixir.bootlin.com/linux/v5.10.8/source/include/linux/kdev_t.h#L39
 *
 * @param major  driver major number
 * @param minor  driver minor number
 *
 * @return
 */
static inline uint32_t netdata_new_encode_dev(uint32_t major, uint32_t minor) {
    return (minor & 0xff) | (major << 8) | ((minor & ~0xff) << 12);
}

/**
 * Compare disks
 *
 * Compare major and minor values to add disks to tree.
 *
 * @param a pointer to netdata_ebpf_disks
 * @param b pointer to netdata_ebpf_disks
 *
 * @return It returns 0 case the values are equal, 1 case a is bigger than b and -1 case a is smaller than b.
*/
static int ebpf_compare_disks(void *a, void *b)
{
    netdata_ebpf_disks_t *ptr1 = a;
    netdata_ebpf_disks_t *ptr2 = b;

    if (ptr1->dev > ptr2->dev)
        return 1;
    if (ptr1->dev < ptr2->dev)
        return -1;

    return 0;
}

/**
 * Update listen table
 *
 * Update link list when it is necessary.
 *
 * @param name         disk name
 * @param major        major disk identifier
 * @param minor        minor disk identifier
 * @param current_time current timestamp
 */
static void update_disk_table(char *name, int major, int minor, time_t current_time)
{
    netdata_ebpf_disks_t find;
    netdata_ebpf_disks_t *w;
    size_t length;

    uint32_t dev = netdata_new_encode_dev(major, minor);
    find.dev = dev;
    netdata_ebpf_disks_t *ret = (netdata_ebpf_disks_t *) avl_search_lock(&disk_tree, (avl_t *)&find);
    if (ret) { // Disk is already present
        ret->flags |= NETDATA_DISK_IS_HERE;
        ret->last_update = current_time;
        return;
    }

    netdata_ebpf_disks_t *update_next = disk_list;
    if (likely(disk_list)) {
        netdata_ebpf_disks_t *move = disk_list;
        while (move) {
            if (dev == move->dev)
                return;

            update_next = move;
            move = move->next;
        }

        w = callocz(1, sizeof(netdata_ebpf_disks_t));
        length = strlen(name);
        if (length >= NETDATA_DISK_NAME_LEN)
            length = NETDATA_DISK_NAME_LEN;

        memcpy(w->family, name, length);
        w->family[length] = '\0';
        w->major = major;
        w->minor = minor;
        w->dev = netdata_new_encode_dev(major, minor);
        update_next->next = w;
    } else {
        disk_list = callocz(1, sizeof(netdata_ebpf_disks_t));
        length = strlen(name);
        if (length >= NETDATA_DISK_NAME_LEN)
            length = NETDATA_DISK_NAME_LEN;

        memcpy(disk_list->family, name, length);
        disk_list->family[length] = '\0';
        disk_list->major = major;
        disk_list->minor = minor;
        disk_list->dev = netdata_new_encode_dev(major, minor);

        w = disk_list;
    }

    ebpf_read_disk_info(w, name);

    netdata_ebpf_disks_t *check;
    check = (netdata_ebpf_disks_t *) avl_insert_lock(&disk_tree, (avl_t *)w);
    if (check != w)
        netdata_log_error("Internal error, cannot insert the AVL tree.");

#ifdef NETDATA_INTERNAL_CHECKS
    netdata_log_info("The Latency is monitoring the hard disk %s (Major = %d, Minor = %d, Device = %u)", name, major, minor,w->dev);
#endif

    w->flags |= NETDATA_DISK_IS_HERE;
}

/**
 *  Read Local Disks
 *
 *  Parse /proc/partitions to get block disks used to measure latency.
 *
 *  @return It returns 0 on success and -1 otherwise
 */
static int read_local_disks()
{
    char filename[FILENAME_MAX + 1];
    snprintfz(filename, FILENAME_MAX, "%s%s", netdata_configured_host_prefix, NETDATA_EBPF_PROC_PARTITIONS);
    procfile *ff = procfile_open(filename, " \t:", PROCFILE_FLAG_DEFAULT);
    if (!ff)
        return -1;

    ff = procfile_readall(ff);
    if (!ff)
        return -1;

    size_t lines = procfile_lines(ff), l;
    time_t current_time = now_realtime_sec();
    for(l = 2; l < lines ;l++) {
        size_t words = procfile_linewords(ff, l);
        // This is header or end of file
        if (unlikely(words < 4))
            continue;

        int major = (int)strtol(procfile_lineword(ff, l, 0), NULL, 10);
        // The main goal of this thread is to measure block devices, so any block device with major number
        // smaller than 7 according /proc/devices is not "important".
        if (major > 7) {
            int minor = (int)strtol(procfile_lineword(ff, l, 1), NULL, 10);
            update_disk_table(procfile_lineword(ff, l, 3), major, minor, current_time);
        }
    }

    procfile_close(ff);

    return 0;
}

/**
 * Update disks
 *
 * @param em main thread structure
 */
void ebpf_update_disks(ebpf_module_t *em)
{
    static time_t update_every = 0;
    time_t curr = now_realtime_sec();
    if (curr < update_every)
        return;

    update_every = curr + 5 * em->update_every;

    (void)read_local_disks();
}

/*****************************************************************
 *
 *  FUNCTIONS TO CLOSE THE THREAD
 *
 *****************************************************************/

/**
 * Disk disable tracepoints
 *
 * Disable tracepoints when the plugin was responsible to enable it.
 */
static void ebpf_disk_disable_tracepoints()
{
    char *default_message = { "Cannot disable the tracepoint" };
    if (!was_block_issue_enabled) {
        if (ebpf_disable_tracing_values(tracepoint_block_type, tracepoint_block_issue))
            netdata_log_error("%s %s/%s.", default_message, tracepoint_block_type, tracepoint_block_issue);
    }

    if (!was_block_rq_complete_enabled) {
        if (ebpf_disable_tracing_values(tracepoint_block_type, tracepoint_block_rq_complete))
            netdata_log_error("%s %s/%s.", default_message, tracepoint_block_type, tracepoint_block_rq_complete);
    }
}

/**
 * Cleanup plot disks
 *
 * Clean disk list
 */
static void ebpf_cleanup_plot_disks()
{
    ebpf_publish_disk_t *move = plot_disks, *next;
    while (move) {
        next = move->next;

        freez(move);

        move = next;
    }
    plot_disks = NULL;
}

/**
 * Cleanup Disk List
 */
static void ebpf_cleanup_disk_list()
{
    netdata_ebpf_disks_t *move = disk_list;
    while (move) {
        netdata_ebpf_disks_t *next = move->next;

        freez(move->histogram.name);
        freez(move->boot_chart);
        freez(move);

        move = next;
    }
    disk_list = NULL;
}

/**
 * Obsolete global
 *
 * Obsolete global charts created by thread.
 *
 * @param em a pointer to `struct ebpf_module`
 */
static void ebpf_obsolete_disk_global(ebpf_module_t *em)
{
    ebpf_publish_disk_t *move = plot_disks;
    while (move) {
        netdata_ebpf_disks_t *ned = move->plot;
        uint32_t flags = ned->flags;
        if (flags & NETDATA_DISK_CHART_CREATED) {
            ebpf_write_chart_obsolete(ned->histogram.name,
                                      ned->family,
                                      "",
                                      "Disk latency",
                                      EBPF_COMMON_DIMENSION_CALL,
                                      ned->family,
                                      NETDATA_EBPF_CHART_TYPE_STACKED,
                                      NULL,
                                      ned->histogram.order,
                                      em->update_every);
        }

        move = move->next;
    }
}

/**
 * Disk exit.
 *
 * Cancel child and exit.
 *
 * @param ptr thread data.
 */
static void ebpf_disk_exit(void *ptr)
{
    ebpf_module_t *em = (ebpf_module_t *)ptr;

    if (em->enabled == NETDATA_THREAD_EBPF_FUNCTION_RUNNING) {
        pthread_mutex_lock(&lock);

        ebpf_obsolete_disk_global(em);

        pthread_mutex_unlock(&lock);
        fflush(stdout);
    }
    ebpf_disk_disable_tracepoints();

    ebpf_update_kernel_memory_with_vector(&plugin_statistics, disk_maps, EBPF_ACTION_STAT_REMOVE);

    if (em->objects) {
        ebpf_unload_legacy_code(em->objects, em->probe_links);
        em->objects = NULL;
        em->probe_links = NULL;
    }

    if (dimensions)
        ebpf_histogram_dimension_cleanup(dimensions, NETDATA_EBPF_HIST_MAX_BINS);

    freez(disk_hash_values);
    disk_hash_values = NULL;
    pthread_mutex_destroy(&plot_mutex);

    ebpf_cleanup_plot_disks();
    ebpf_cleanup_disk_list();

    pthread_mutex_lock(&ebpf_exit_cleanup);
    em->enabled = NETDATA_THREAD_EBPF_STOPPED;
    ebpf_update_stats(&plugin_statistics, em);
    pthread_mutex_unlock(&ebpf_exit_cleanup);
}

/*****************************************************************
 *
 *  MAIN LOOP
 *
 *****************************************************************/

/**
 * Fill Plot list
 *
 * @param ptr a pointer for current disk
 */
static void ebpf_fill_plot_disks(netdata_ebpf_disks_t *ptr)
{
    pthread_mutex_lock(&plot_mutex);
    ebpf_publish_disk_t *w;
    if (likely(plot_disks)) {
        ebpf_publish_disk_t *move = plot_disks, *store = plot_disks;
        while (move) {
            if (move->plot == ptr) {
                pthread_mutex_unlock(&plot_mutex);
                return;
            }

            store = move;
            move = move->next;
        }

        w = callocz(1, sizeof(ebpf_publish_disk_t));
        w->plot = ptr;
        store->next = w;
    } else {
        plot_disks = callocz(1, sizeof(ebpf_publish_disk_t));
        plot_disks->plot = ptr;
    }
    pthread_mutex_unlock(&plot_mutex);

    ptr->flags |= NETDATA_DISK_ADDED_TO_PLOT_LIST;
}

/**
 * Read hard disk table
 *
 * Read the table with number of calls for all functions
 *
 * @param table file descriptor for table
 * @param maps_per_core do I need to read all cores?
 */
static void read_hard_disk_tables(int table, int maps_per_core)
{
    netdata_idx_t *values = disk_hash_values;
    block_key_t key = {};
    block_key_t next_key = {};

    netdata_ebpf_disks_t *ret = NULL;

    while (bpf_map_get_next_key(table, &key, &next_key) == 0) {
        int test = bpf_map_lookup_elem(table, &key, values);
        if (test < 0) {
            key = next_key;
            continue;
        }

        netdata_ebpf_disks_t find;
        find.dev = key.dev;

        if (likely(ret)) {
            if (find.dev != ret->dev)
                ret = (netdata_ebpf_disks_t *)avl_search_lock(&disk_tree, (avl_t *)&find);
        } else
            ret = (netdata_ebpf_disks_t *)avl_search_lock(&disk_tree, (avl_t *)&find);

        // Disk was inserted after we parse /proc/partitions
        if (!ret) {
            if (read_local_disks()) {
                key = next_key;
                continue;
            }

            ret = (netdata_ebpf_disks_t *)avl_search_lock(&disk_tree, (avl_t *)&find);
            if (!ret) {
                // We should never reach this point, but we are adding it to keep a safe code
                key = next_key;
                continue;
            }
        }

        uint64_t total = 0;
        int i;
        int end = (maps_per_core) ? 1 : ebpf_nprocs;
        for (i = 0; i < end; i++) {
            total += values[i];
        }

        ret->histogram.histogram[key.bin] = total;

        if (!(ret->flags & NETDATA_DISK_ADDED_TO_PLOT_LIST))
            ebpf_fill_plot_disks(ret);

        key = next_key;
    }
}

/**
 * Obsolete Hard Disk charts
 *
 * Make Hard disk charts and fill chart name
 *
 * @param w the structure with necessary information to create the chart
 * @param update_every value to overwrite the update frequency set by the server.
 */
static void ebpf_obsolete_hd_charts(netdata_ebpf_disks_t *w, int update_every)
{
    ebpf_write_chart_obsolete(w->histogram.name, w->family, "", w->histogram.title, EBPF_COMMON_DIMENSION_CALL,
                              w->family, NETDATA_EBPF_CHART_TYPE_STACKED, "disk.latency_io",
                              w->histogram.order, update_every);

    w->flags = 0;
}

/**
 * Create Hard Disk charts
 *
 * Make Hard disk charts and fill chart name
 *
 * @param w the structure with necessary information to create the chart
 * @param update_every value to overwrite the update frequency set by the server.
 */
static void ebpf_create_hd_charts(netdata_ebpf_disks_t *w, int update_every)
{
    int order = NETDATA_CHART_PRIO_DISK_LATENCY;
    char *family = w->family;

    w->histogram.name = strdupz("disk_latency_io");
    w->histogram.title = NULL;
    w->histogram.order = order;

    ebpf_create_chart(w->histogram.name, family, "Disk latency", EBPF_COMMON_DIMENSION_CALL,
                      family, "disk.latency_io", NETDATA_EBPF_CHART_TYPE_STACKED, order,
                      ebpf_create_global_dimension, disk_publish_aggregated, NETDATA_EBPF_HIST_MAX_BINS,
                      update_every, NETDATA_EBPF_MODULE_NAME_DISK);
    order++;

    w->flags |= NETDATA_DISK_CHART_CREATED;

    fflush(stdout);
}

/**
 * Remove pointer from plot
 *
 * Remove pointer from plot list when the disk is not present.
 */
static void ebpf_remove_pointer_from_plot_disk(ebpf_module_t *em)
{
    time_t current_time = now_realtime_sec();
    time_t limit = 10 * em->update_every;
    pthread_mutex_lock(&plot_mutex);
    ebpf_publish_disk_t *move = plot_disks, *prev = plot_disks;
    int update_every = em->update_every;
    while (move) {
        netdata_ebpf_disks_t *ned = move->plot;
        uint32_t flags = ned->flags;

        if (!(flags & NETDATA_DISK_IS_HERE) && ((current_time - ned->last_update) > limit)) {
            ebpf_obsolete_hd_charts(ned, update_every);
            avl_t *ret = (avl_t *)avl_remove_lock(&disk_tree, (avl_t *)ned);
            UNUSED(ret);
            if (move == plot_disks) {
                freez(move);
                plot_disks = NULL;
                break;
            } else {
                prev->next = move->next;
                ebpf_publish_disk_t *clean = move;
                move = move->next;
                freez(clean);
                continue;
            }
        }

        prev = move;
        move = move->next;
    }
    pthread_mutex_unlock(&plot_mutex);
}

/**
 * Send Hard disk data
 *
 * Send hard disk information to Netdata.
 *
 * @param update_every value to overwrite the update frequency set by the server.
 */
static void ebpf_latency_send_hd_data(int update_every)
{
    pthread_mutex_lock(&plot_mutex);
    if (!plot_disks) {
        pthread_mutex_unlock(&plot_mutex);
        return;
    }

    ebpf_publish_disk_t *move = plot_disks;
    while (move) {
        netdata_ebpf_disks_t *ned = move->plot;
        uint32_t flags = ned->flags;
        if (!(flags & NETDATA_DISK_CHART_CREATED)) {
            ebpf_create_hd_charts(ned, update_every);
        }

        if ((flags & NETDATA_DISK_CHART_CREATED)) {
            write_histogram_chart(ned->histogram.name, ned->family,
                                  ned->histogram.histogram, dimensions, NETDATA_EBPF_HIST_MAX_BINS);
        }

        ned->flags &= ~NETDATA_DISK_IS_HERE;

        move = move->next;
    }
    pthread_mutex_unlock(&plot_mutex);
}

/**
* Main loop for this collector.
*/
static void disk_collector(ebpf_module_t *em)
{
    disk_hash_values = callocz(ebpf_nprocs, sizeof(netdata_idx_t));

    int update_every = em->update_every;
    heartbeat_t hb;
    heartbeat_init(&hb);
    int counter = update_every - 1;
    int maps_per_core = em->maps_per_core;
    uint32_t running_time = 0;
    uint32_t lifetime = em->lifetime;
    while (!ebpf_plugin_exit && running_time < lifetime) {
        (void)heartbeat_next(&hb, USEC_PER_SEC);

        if (ebpf_plugin_exit || ++counter != update_every)
            continue;

        counter = 0;
        read_hard_disk_tables(disk_maps[NETDATA_DISK_IO].map_fd, maps_per_core);
        pthread_mutex_lock(&lock);
        ebpf_remove_pointer_from_plot_disk(em);
        ebpf_latency_send_hd_data(update_every);

        pthread_mutex_unlock(&lock);

        ebpf_update_disks(em);

        pthread_mutex_lock(&ebpf_exit_cleanup);
        if (running_time && !em->running_time)
            running_time = update_every;
        else
            running_time += update_every;

        em->running_time = running_time;
        pthread_mutex_unlock(&ebpf_exit_cleanup);
    }
}

/*****************************************************************
 *
 *  EBPF DISK THREAD
 *
 *****************************************************************/

/**
 * Enable tracepoints
 *
 * Enable necessary tracepoints for thread.
 *
 * @return  It returns 0 on success and -1 otherwise
 */
static int ebpf_disk_enable_tracepoints()
{
    int test = ebpf_is_tracepoint_enabled(tracepoint_block_type, tracepoint_block_issue);
    if (test == -1)
        return -1;
    else if (!test) {
        if (ebpf_enable_tracing_values(tracepoint_block_type, tracepoint_block_issue))
            return -1;
    }
    was_block_issue_enabled = test;

    test = ebpf_is_tracepoint_enabled(tracepoint_block_type, tracepoint_block_rq_complete);
    if (test == -1)
        return -1;
    else if (!test) {
        if (ebpf_enable_tracing_values(tracepoint_block_type, tracepoint_block_rq_complete))
            return -1;
    }
    was_block_rq_complete_enabled = test;

    return 0;
}

/*
 * Load BPF
 *
 * Load BPF files.
 *
 * @param em the structure with configuration
 *
 * @return It returns 0 on success and -1 otherwise.
 */
static int ebpf_disk_load_bpf(ebpf_module_t *em)
{
    int ret = 0;
    if (em->load & EBPF_LOAD_LEGACY) {
        em->probe_links = ebpf_load_program(ebpf_plugin_dir, em, running_on_kernel, isrh, &em->objects);
        if (!em->probe_links) {
            ret = -1;
        }
    }
#ifdef LIBBPF_MAJOR_VERSION
    else {
        disk_bpf_obj = disk_bpf__open();
        if (!disk_bpf_obj)
            ret = -1;
        else {
            ret = ebpf_disk_load_and_attach(disk_bpf_obj);
            if (!ret)
                ebpf_disk_set_hash_table(disk_bpf_obj);
        }
    }
#endif

    if (ret)
        netdata_log_error("%s %s", EBPF_DEFAULT_ERROR_MSG, em->info.thread_name);

    return ret;
}

/**
 * Disk thread
 *
 * Thread used to generate disk charts.
 *
 * @param ptr a pointer to `struct ebpf_module`
 *
 * @return It always return NULL
 */
void *ebpf_disk_thread(void *ptr)
{
    netdata_thread_cleanup_push(ebpf_disk_exit, ptr);

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

    if (ebpf_disk_enable_tracepoints()) {
        goto enddisk;
    }

    avl_init_lock(&disk_tree, ebpf_compare_disks);
    if (read_local_disks()) {
        goto enddisk;
    }

    if (pthread_mutex_init(&plot_mutex, NULL)) {
        netdata_log_error("Cannot initialize local mutex");
        goto enddisk;
    }

#ifdef LIBBPF_MAJOR_VERSION
    ebpf_define_map_type(disk_maps, em->maps_per_core, running_on_kernel);
    ebpf_adjust_thread_load(em, default_btf);
#endif
    if (ebpf_disk_load_bpf(em)) {
        goto enddisk;
    }

    int algorithms[NETDATA_EBPF_HIST_MAX_BINS];
    ebpf_fill_algorithms(algorithms, NETDATA_EBPF_HIST_MAX_BINS, NETDATA_EBPF_INCREMENTAL_IDX);
    dimensions = ebpf_fill_histogram_dimension(NETDATA_EBPF_HIST_MAX_BINS);

    ebpf_global_labels(disk_aggregated_data, disk_publish_aggregated, dimensions, dimensions, algorithms,
                       NETDATA_EBPF_HIST_MAX_BINS);

    pthread_mutex_lock(&lock);
    ebpf_update_stats(&plugin_statistics, em);
    ebpf_update_kernel_memory_with_vector(&plugin_statistics, disk_maps, EBPF_ACTION_STAT_ADD);
    pthread_mutex_unlock(&lock);

    disk_collector(em);

enddisk:
    ebpf_update_disabled_plugin_stats(em);

    netdata_thread_cleanup_pop(1);

    return NULL;
}