summaryrefslogtreecommitdiff
path: root/tools/mm/thpmaps
blob: 803e0318f2fea1c5cc19e036316c6d00fb407783 (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
#!/usr/bin/env python3
# SPDX-License-Identifier: GPL-2.0-only
# Copyright (C) 2024 ARM Ltd.
#
# Utility providing smaps-like output detailing transparent hugepage usage.
# For more info, run:
# ./thpmaps --help
#
# Requires numpy:
# pip3 install numpy


import argparse
import collections
import math
import os
import re
import resource
import shutil
import sys
import textwrap
import time
import numpy as np


with open('/sys/kernel/mm/transparent_hugepage/hpage_pmd_size') as f:
    PAGE_SIZE = resource.getpagesize()
    PAGE_SHIFT = int(math.log2(PAGE_SIZE))
    PMD_SIZE = int(f.read())
    PMD_ORDER = int(math.log2(PMD_SIZE / PAGE_SIZE))


def align_forward(v, a):
    return (v + (a - 1)) & ~(a - 1)


def align_offset(v, a):
    return v & (a - 1)


def kbnr(kb):
    # Convert KB to number of pages.
    return (kb << 10) >> PAGE_SHIFT


def nrkb(nr):
    # Convert number of pages to KB.
    return (nr << PAGE_SHIFT) >> 10


def odkb(order):
    # Convert page order to KB.
    return (PAGE_SIZE << order) >> 10


def cont_ranges_all(search, index):
    # Given a list of arrays, find the ranges for which values are monotonically
    # incrementing in all arrays. all arrays in search and index must be the
    # same size.
    sz = len(search[0])
    r = np.full(sz, 2)
    d = np.diff(search[0]) == 1
    for dd in [np.diff(arr) == 1 for arr in search[1:]]:
        d &= dd
    r[1:] -= d
    r[:-1] -= d
    return [np.repeat(arr, r).reshape(-1, 2) for arr in index]


class ArgException(Exception):
    pass


class FileIOException(Exception):
    pass


class BinArrayFile:
    # Base class used to read /proc/<pid>/pagemap and /proc/kpageflags into a
    # numpy array. Use inherrited class in a with clause to ensure file is
    # closed when it goes out of scope.
    def __init__(self, filename, element_size):
        self.element_size = element_size
        self.filename = filename
        self.fd = os.open(self.filename, os.O_RDONLY)

    def cleanup(self):
        os.close(self.fd)

    def __enter__(self):
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.cleanup()

    def _readin(self, offset, buffer):
        length = os.preadv(self.fd, (buffer,), offset)
        if len(buffer) != length:
            raise FileIOException('error: {} failed to read {} bytes at {:x}'
                            .format(self.filename, len(buffer), offset))

    def _toarray(self, buf):
        assert(self.element_size == 8)
        return np.frombuffer(buf, dtype=np.uint64)

    def getv(self, vec):
        vec *= self.element_size
        offsets = vec[:, 0]
        lengths = (np.diff(vec) + self.element_size).reshape(len(vec))
        buf = bytearray(int(np.sum(lengths)))
        view = memoryview(buf)
        pos = 0
        for offset, length in zip(offsets, lengths):
            offset = int(offset)
            length = int(length)
            self._readin(offset, view[pos:pos+length])
            pos += length
        return self._toarray(buf)

    def get(self, index, nr=1):
        offset = index * self.element_size
        length = nr * self.element_size
        buf = bytearray(length)
        self._readin(offset, buf)
        return self._toarray(buf)


PM_PAGE_PRESENT = 1 << 63
PM_PFN_MASK = (1 << 55) - 1

class PageMap(BinArrayFile):
    # Read ranges of a given pid's pagemap into a numpy array.
    def __init__(self, pid='self'):
        super().__init__(f'/proc/{pid}/pagemap', 8)


KPF_ANON = 1 << 12
KPF_COMPOUND_HEAD = 1 << 15
KPF_COMPOUND_TAIL = 1 << 16
KPF_THP = 1 << 22

class KPageFlags(BinArrayFile):
    # Read ranges of /proc/kpageflags into a numpy array.
    def __init__(self):
         super().__init__(f'/proc/kpageflags', 8)


vma_all_stats = set([
    "Size",
    "Rss",
    "Pss",
    "Pss_Dirty",
    "Shared_Clean",
    "Shared_Dirty",
    "Private_Clean",
    "Private_Dirty",
    "Referenced",
    "Anonymous",
    "KSM",
    "LazyFree",
    "AnonHugePages",
    "ShmemPmdMapped",
    "FilePmdMapped",
    "Shared_Hugetlb",
    "Private_Hugetlb",
    "Swap",
    "SwapPss",
    "Locked",
])

vma_min_stats = set([
    "Rss",
    "Anonymous",
    "AnonHugePages",
    "ShmemPmdMapped",
    "FilePmdMapped",
])

VMA = collections.namedtuple('VMA', [
    'name',
    'start',
    'end',
    'read',
    'write',
    'execute',
    'private',
    'pgoff',
    'major',
    'minor',
    'inode',
    'stats',
])

class VMAList:
    # A container for VMAs, parsed from /proc/<pid>/smaps. Iterate over the
    # instance to receive VMAs.
    def __init__(self, pid='self', stats=[]):
        self.vmas = []
        with open(f'/proc/{pid}/smaps', 'r') as file:
            for line in file:
                elements = line.split()
                if '-' in elements[0]:
                    start, end = map(lambda x: int(x, 16), elements[0].split('-'))
                    major, minor = map(lambda x: int(x, 16), elements[3].split(':'))
                    self.vmas.append(VMA(
                        name=elements[5] if len(elements) == 6 else '',
                        start=start,
                        end=end,
                        read=elements[1][0] == 'r',
                        write=elements[1][1] == 'w',
                        execute=elements[1][2] == 'x',
                        private=elements[1][3] == 'p',
                        pgoff=int(elements[2], 16),
                        major=major,
                        minor=minor,
                        inode=int(elements[4], 16),
                        stats={},
                    ))
                else:
                    param = elements[0][:-1]
                    if param in stats:
                        value = int(elements[1])
                        self.vmas[-1].stats[param] = {'type': None, 'value': value}

    def __iter__(self):
        yield from self.vmas


def thp_parse(vma, kpageflags, ranges, indexes, vfns, pfns, anons, heads):
    # Given 4 same-sized arrays representing a range within a page table backed
    # by THPs (vfns: virtual frame numbers, pfns: physical frame numbers, anons:
    # True if page is anonymous, heads: True if page is head of a THP), return a
    # dictionary of statistics describing the mapped THPs.
    stats = {
        'file': {
            'partial': 0,
            'aligned': [0] * (PMD_ORDER + 1),
            'unaligned': [0] * (PMD_ORDER + 1),
        },
        'anon': {
            'partial': 0,
            'aligned': [0] * (PMD_ORDER + 1),
            'unaligned': [0] * (PMD_ORDER + 1),
        },
    }

    for rindex, rpfn in zip(ranges[0], ranges[2]):
        index_next = int(rindex[0])
        index_end = int(rindex[1]) + 1
        pfn_end = int(rpfn[1]) + 1

        folios = indexes[index_next:index_end][heads[index_next:index_end]]

        # Account pages for any partially mapped THP at the front. In that case,
        # the first page of the range is a tail.
        nr = (int(folios[0]) if len(folios) else index_end) - index_next
        stats['anon' if anons[index_next] else 'file']['partial'] += nr

        # Account pages for any partially mapped THP at the back. In that case,
        # the next page after the range is a tail.
        if len(folios):
            flags = int(kpageflags.get(pfn_end)[0])
            if flags & KPF_COMPOUND_TAIL:
                nr = index_end - int(folios[-1])
                folios = folios[:-1]
                index_end -= nr
                stats['anon' if anons[index_end - 1] else 'file']['partial'] += nr

        # Account fully mapped THPs in the middle of the range.
        if len(folios):
            folio_nrs = np.append(np.diff(folios), np.uint64(index_end - folios[-1]))
            folio_orders = np.log2(folio_nrs).astype(np.uint64)
            for index, order in zip(folios, folio_orders):
                index = int(index)
                order = int(order)
                nr = 1 << order
                vfn = int(vfns[index])
                align = 'aligned' if align_forward(vfn, nr) == vfn else 'unaligned'
                anon = 'anon' if anons[index] else 'file'
                stats[anon][align][order] += nr

    # Account PMD-mapped THPs spearately, so filter out of the stats. There is a
    # race between acquiring the smaps stats and reading pagemap, where memory
    # could be deallocated. So clamp to zero incase it would have gone negative.
    anon_pmd_mapped = vma.stats['AnonHugePages']['value']
    file_pmd_mapped = vma.stats['ShmemPmdMapped']['value'] + \
                      vma.stats['FilePmdMapped']['value']
    stats['anon']['aligned'][PMD_ORDER] = max(0, stats['anon']['aligned'][PMD_ORDER] - kbnr(anon_pmd_mapped))
    stats['file']['aligned'][PMD_ORDER] = max(0, stats['file']['aligned'][PMD_ORDER] - kbnr(file_pmd_mapped))

    rstats = {
        f"anon-thp-pmd-aligned-{odkb(PMD_ORDER)}kB": {'type': 'anon', 'value': anon_pmd_mapped},
        f"file-thp-pmd-aligned-{odkb(PMD_ORDER)}kB": {'type': 'file', 'value': file_pmd_mapped},
    }

    def flatten_sub(type, subtype, stats):
        param = f"{type}-thp-pte-{subtype}-{{}}kB"
        for od, nr in enumerate(stats[2:], 2):
            rstats[param.format(odkb(od))] = {'type': type, 'value': nrkb(nr)}

    def flatten_type(type, stats):
        flatten_sub(type, 'aligned', stats['aligned'])
        flatten_sub(type, 'unaligned', stats['unaligned'])
        rstats[f"{type}-thp-pte-partial"] = {'type': type, 'value': nrkb(stats['partial'])}

    flatten_type('anon', stats['anon'])
    flatten_type('file', stats['file'])

    return rstats


def cont_parse(vma, order, ranges, anons, heads):
    # Given 4 same-sized arrays representing a range within a page table backed
    # by THPs (vfns: virtual frame numbers, pfns: physical frame numbers, anons:
    # True if page is anonymous, heads: True if page is head of a THP), return a
    # dictionary of statistics describing the contiguous blocks.
    nr_cont = 1 << order
    nr_anon = 0
    nr_file = 0

    for rindex, rvfn, rpfn in zip(*ranges):
        index_next = int(rindex[0])
        index_end = int(rindex[1]) + 1
        vfn_start = int(rvfn[0])
        pfn_start = int(rpfn[0])

        if align_offset(pfn_start, nr_cont) != align_offset(vfn_start, nr_cont):
            continue

        off = align_forward(vfn_start, nr_cont) - vfn_start
        index_next += off

        while index_next + nr_cont <= index_end:
            folio_boundary = heads[index_next+1:index_next+nr_cont].any()
            if not folio_boundary:
                if anons[index_next]:
                    nr_anon += nr_cont
                else:
                    nr_file += nr_cont
            index_next += nr_cont

    # Account blocks that are PMD-mapped spearately, so filter out of the stats.
    # There is a race between acquiring the smaps stats and reading pagemap,
    # where memory could be deallocated. So clamp to zero incase it would have
    # gone negative.
    anon_pmd_mapped = vma.stats['AnonHugePages']['value']
    file_pmd_mapped = vma.stats['ShmemPmdMapped']['value'] + \
                    vma.stats['FilePmdMapped']['value']
    nr_anon = max(0, nr_anon - kbnr(anon_pmd_mapped))
    nr_file = max(0, nr_file - kbnr(file_pmd_mapped))

    rstats = {
        f"anon-cont-pmd-aligned-{nrkb(nr_cont)}kB": {'type': 'anon', 'value': anon_pmd_mapped},
        f"file-cont-pmd-aligned-{nrkb(nr_cont)}kB": {'type': 'file', 'value': file_pmd_mapped},
    }

    rstats[f"anon-cont-pte-aligned-{nrkb(nr_cont)}kB"] = {'type': 'anon', 'value': nrkb(nr_anon)}
    rstats[f"file-cont-pte-aligned-{nrkb(nr_cont)}kB"] = {'type': 'file', 'value': nrkb(nr_file)}

    return rstats


def vma_print(vma, pid):
    # Prints a VMA instance in a format similar to smaps. The main difference is
    # that the pid is included as the first value.
    print("{:010d}: {:016x}-{:016x} {}{}{}{} {:08x} {:02x}:{:02x} {:08x} {}"
        .format(
            pid, vma.start, vma.end,
            'r' if vma.read else '-', 'w' if vma.write else '-',
            'x' if vma.execute else '-', 'p' if vma.private else 's',
            vma.pgoff, vma.major, vma.minor, vma.inode, vma.name
        ))


def stats_print(stats, tot_anon, tot_file, inc_empty):
    # Print a statistics dictionary.
    label_field = 32
    for label, stat in stats.items():
        type = stat['type']
        value = stat['value']
        if value or inc_empty:
            pad = max(0, label_field - len(label) - 1)
            if type == 'anon' and tot_anon > 0:
                percent = f' ({value / tot_anon:3.0%})'
            elif type == 'file' and tot_file > 0:
                percent = f' ({value / tot_file:3.0%})'
            else:
                percent = ''
            print(f"{label}:{' ' * pad}{value:8} kB{percent}")


def vma_parse(vma, pagemap, kpageflags, contorders):
    # Generate thp and cont statistics for a single VMA.
    start = vma.start >> PAGE_SHIFT
    end = vma.end >> PAGE_SHIFT

    pmes = pagemap.get(start, end - start)
    present = pmes & PM_PAGE_PRESENT != 0
    pfns = pmes & PM_PFN_MASK
    pfns = pfns[present]
    vfns = np.arange(start, end, dtype=np.uint64)
    vfns = vfns[present]

    pfn_vec = cont_ranges_all([pfns], [pfns])[0]
    flags = kpageflags.getv(pfn_vec)
    anons = flags & KPF_ANON != 0
    heads = flags & KPF_COMPOUND_HEAD != 0
    thps = flags & KPF_THP != 0

    vfns = vfns[thps]
    pfns = pfns[thps]
    anons = anons[thps]
    heads = heads[thps]

    indexes = np.arange(len(vfns), dtype=np.uint64)
    ranges = cont_ranges_all([vfns, pfns], [indexes, vfns, pfns])

    thpstats = thp_parse(vma, kpageflags, ranges, indexes, vfns, pfns, anons, heads)
    contstats = [cont_parse(vma, order, ranges, anons, heads) for order in contorders]

    tot_anon = vma.stats['Anonymous']['value']
    tot_file = vma.stats['Rss']['value'] - tot_anon

    return {
        **thpstats,
        **{k: v for s in contstats for k, v in s.items()}
    }, tot_anon, tot_file


def do_main(args):
    pids = set()
    rollup = {}
    rollup_anon = 0
    rollup_file = 0

    if args.cgroup:
        strict = False
        for walk_info in os.walk(args.cgroup):
            cgroup = walk_info[0]
            with open(f'{cgroup}/cgroup.procs') as pidfile:
                for line in pidfile.readlines():
                    pids.add(int(line.strip()))
    elif args.pid:
        strict = True
        pids = pids.union(args.pid)
    else:
        strict = False
        for pid in os.listdir('/proc'):
            if pid.isdigit():
                pids.add(int(pid))

    if not args.rollup:
        print("       PID             START              END PROT   OFFSET   DEV    INODE OBJECT")

    for pid in pids:
        try:
            with PageMap(pid) as pagemap:
                with KPageFlags() as kpageflags:
                    for vma in VMAList(pid, vma_all_stats if args.inc_smaps else vma_min_stats):
                        if (vma.read or vma.write or vma.execute) and vma.stats['Rss']['value'] > 0:
                            stats, vma_anon, vma_file = vma_parse(vma, pagemap, kpageflags, args.cont)
                        else:
                            stats = {}
                            vma_anon = 0
                            vma_file = 0
                        if args.inc_smaps:
                            stats = {**vma.stats, **stats}
                        if args.rollup:
                            for k, v in stats.items():
                                if k in rollup:
                                    assert(rollup[k]['type'] == v['type'])
                                    rollup[k]['value'] += v['value']
                                else:
                                    rollup[k] = v
                            rollup_anon += vma_anon
                            rollup_file += vma_file
                        else:
                            vma_print(vma, pid)
                            stats_print(stats, vma_anon, vma_file, args.inc_empty)
        except (FileNotFoundError, ProcessLookupError, FileIOException):
            if strict:
                raise

    if args.rollup:
        stats_print(rollup, rollup_anon, rollup_file, args.inc_empty)


def main():
    docs_width = shutil.get_terminal_size().columns
    docs_width -= 2
    docs_width = min(80, docs_width)

    def format(string):
        text = re.sub(r'\s+', ' ', string)
        text = re.sub(r'\s*\\n\s*', '\n', text)
        paras = text.split('\n')
        paras = [textwrap.fill(p, width=docs_width) for p in paras]
        return '\n'.join(paras)

    def formatter(prog):
        return argparse.RawDescriptionHelpFormatter(prog, width=docs_width)

    def size2order(human):
        units = {
            "K": 2**10, "M": 2**20, "G": 2**30,
            "k": 2**10, "m": 2**20, "g": 2**30,
        }
        unit = 1
        if human[-1] in units:
            unit = units[human[-1]]
            human = human[:-1]
        try:
            size = int(human)
        except ValueError:
            raise ArgException('error: --cont value must be integer size with optional KMG unit')
        size *= unit
        order = int(math.log2(size / PAGE_SIZE))
        if order < 1:
            raise ArgException('error: --cont value must be size of at least 2 pages')
        if (1 << order) * PAGE_SIZE != size:
            raise ArgException('error: --cont value must be size of power-of-2 pages')
        if order > PMD_ORDER:
            raise ArgException('error: --cont value must be less than or equal to PMD order')
        return order

    parser = argparse.ArgumentParser(formatter_class=formatter,
        description=format("""Prints information about how transparent huge
                    pages are mapped, either system-wide, or for a specified
                    process or cgroup.\\n
                    \\n
                    When run with --pid, the user explicitly specifies the set
                    of pids to scan. e.g. "--pid 10 [--pid 134 ...]". When run
                    with --cgroup, the user passes either a v1 or v2 cgroup and
                    all pids that belong to the cgroup subtree are scanned. When
                    run with neither --pid nor --cgroup, the full set of pids on
                    the system is gathered from /proc and scanned as if the user
                    had provided "--pid 1 --pid 2 ...".\\n
                    \\n
                    A default set of statistics is always generated for THP
                    mappings. However, it is also possible to generate
                    additional statistics for "contiguous block mappings" where
                    the block size is user-defined.\\n
                    \\n
                    Statistics are maintained independently for anonymous and
                    file-backed (pagecache) memory and are shown both in kB and
                    as a percentage of either total anonymous or total
                    file-backed memory as appropriate.\\n
                    \\n
                    THP Statistics\\n
                    --------------\\n
                    \\n
                    Statistics are always generated for fully- and
                    contiguously-mapped THPs whose mapping address is aligned to
                    their size, for each <size> supported by the system.
                    Separate counters describe THPs mapped by PTE vs those
                    mapped by PMD. (Although note a THP can only be mapped by
                    PMD if it is PMD-sized):\\n
                    \\n
                    - anon-thp-pte-aligned-<size>kB\\n
                    - file-thp-pte-aligned-<size>kB\\n
                    - anon-thp-pmd-aligned-<size>kB\\n
                    - file-thp-pmd-aligned-<size>kB\\n
                    \\n
                    Similarly, statistics are always generated for fully- and
                    contiguously-mapped THPs whose mapping address is *not*
                    aligned to their size, for each <size> supported by the
                    system. Due to the unaligned mapping, it is impossible to
                    map by PMD, so there are only PTE counters for this case:\\n
                    \\n
                    - anon-thp-pte-unaligned-<size>kB\\n
                    - file-thp-pte-unaligned-<size>kB\\n
                    \\n
                    Statistics are also always generated for mapped pages that
                    belong to a THP but where the is THP is *not* fully- and
                    contiguously- mapped. These "partial" mappings are all
                    counted in the same counter regardless of the size of the
                    THP that is partially mapped:\\n
                    \\n
                    - anon-thp-pte-partial\\n
                    - file-thp-pte-partial\\n
                    \\n
                    Contiguous Block Statistics\\n
                    ---------------------------\\n
                    \\n
                    An optional, additional set of statistics is generated for
                    every contiguous block size specified with `--cont <size>`.
                    These statistics show how much memory is mapped in
                    contiguous blocks of <size> and also aligned to <size>. A
                    given contiguous block must all belong to the same THP, but
                    there is no requirement for it to be the *whole* THP.
                    Separate counters describe contiguous blocks mapped by PTE
                    vs those mapped by PMD:\\n
                    \\n
                    - anon-cont-pte-aligned-<size>kB\\n
                    - file-cont-pte-aligned-<size>kB\\n
                    - anon-cont-pmd-aligned-<size>kB\\n
                    - file-cont-pmd-aligned-<size>kB\\n
                    \\n
                    As an example, if monitoring 64K contiguous blocks (--cont
                    64K), there are a number of sources that could provide such
                    blocks: a fully- and contiguously-mapped 64K THP that is
                    aligned to a 64K boundary would provide 1 block. A fully-
                    and contiguously-mapped 128K THP that is aligned to at least
                    a 64K boundary would provide 2 blocks. Or a 128K THP that
                    maps its first 100K, but contiguously and starting at a 64K
                    boundary would provide 1 block. A fully- and
                    contiguously-mapped 2M THP would provide 32 blocks. There
                    are many other possible permutations.\\n"""),
        epilog=format("""Requires root privilege to access pagemap and
                    kpageflags."""))

    group = parser.add_mutually_exclusive_group(required=False)
    group.add_argument('--pid',
        metavar='pid', required=False, type=int, default=[], action='append',
        help="""Process id of the target process. Maybe issued multiple times to
            scan multiple processes. --pid and --cgroup are mutually exclusive.
            If neither are provided, all processes are scanned to provide
            system-wide information.""")

    group.add_argument('--cgroup',
        metavar='path', required=False,
        help="""Path to the target cgroup in sysfs. Iterates over every pid in
            the cgroup and its children. --pid and --cgroup are mutually
            exclusive. If neither are provided, all processes are scanned to
            provide system-wide information.""")

    parser.add_argument('--rollup',
        required=False, default=False, action='store_true',
        help="""Sum the per-vma statistics to provide a summary over the whole
            system, process or cgroup.""")

    parser.add_argument('--cont',
        metavar='size[KMG]', required=False, default=[], action='append',
        help="""Adds stats for memory that is mapped in contiguous blocks of
            <size> and also aligned to <size>. May be issued multiple times to
            track multiple sized blocks. Useful to infer e.g. arm64 contpte and
            hpa mappings. Size must be a power-of-2 number of pages.""")

    parser.add_argument('--inc-smaps',
        required=False, default=False, action='store_true',
        help="""Include all numerical, additive /proc/<pid>/smaps stats in the
            output.""")

    parser.add_argument('--inc-empty',
        required=False, default=False, action='store_true',
        help="""Show all statistics including those whose value is 0.""")

    parser.add_argument('--periodic',
        metavar='sleep_ms', required=False, type=int,
        help="""Run in a loop, polling every sleep_ms milliseconds.""")

    args = parser.parse_args()

    try:
        args.cont = [size2order(cont) for cont in args.cont]
    except ArgException as e:
        parser.print_usage()
        raise

    if args.periodic:
        while True:
            do_main(args)
            print()
            time.sleep(args.periodic / 1000)
    else:
        do_main(args)


if __name__ == "__main__":
    try:
        main()
    except Exception as e:
        prog = os.path.basename(sys.argv[0])
        print(f'{prog}: {e}')
        exit(1)