Merging upstream version 6.9.7.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 680 insertions, 4 deletions

diff --git a/tools/mm/Makefile b/tools/mm/Makefile
index 1c5606cc33..7bb03606b9 100644
--- a/tools/mm/Makefile
+++ b/tools/mm/Makefile
@@ -3,7 +3,8 @@
 #
 include ../scripts/Makefile.include
 
-TARGETS=page-types slabinfo page_owner_sort
+BUILD_TARGETS=page-types slabinfo page_owner_sort
+INSTALL_TARGETS = $(BUILD_TARGETS) thpmaps
 
 LIB_DIR = ../lib/api
 LIBS = $(LIB_DIR)/libapi.a
@@ -11,9 +12,9 @@ LIBS = $(LIB_DIR)/libapi.a
 CFLAGS += -Wall -Wextra -I../lib/ -pthread
 LDFLAGS += $(LIBS) -pthread
 
-all: $(TARGETS)
+all: $(BUILD_TARGETS)
 
-$(TARGETS): $(LIBS)
+$(BUILD_TARGETS): $(LIBS)
 
 $(LIBS):
 	make -C $(LIB_DIR)
@@ -29,4 +30,4 @@ sbindir ?= /usr/sbin
 
 install: all
 	install -d $(DESTDIR)$(sbindir)
-	install -m 755 -p $(TARGETS) $(DESTDIR)$(sbindir)
+	install -m 755 -p $(INSTALL_TARGETS) $(DESTDIR)$(sbindir)
diff --git a/tools/mm/thpmaps b/tools/mm/thpmaps
new file mode 100644
index 0000000000..803e0318f2
--- /dev/null
+++ b/tools/mm/thpmaps
@@ -0,0 +1,675 @@
+#!/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)