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581c785bf3
I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
202 lines
5.0 KiB
C
202 lines
5.0 KiB
C
/* Huge Page support. Linux implementation.
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Copyright (C) 2021-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, see <https://www.gnu.org/licenses/>. */
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#include <intprops.h>
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#include <dirent.h>
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#include <malloc-hugepages.h>
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#include <not-cancel.h>
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#include <sys/mman.h>
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unsigned long int
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__malloc_default_thp_pagesize (void)
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{
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int fd = __open64_nocancel (
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"/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", O_RDONLY);
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if (fd == -1)
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return 0;
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char str[INT_BUFSIZE_BOUND (unsigned long int)];
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ssize_t s = __read_nocancel (fd, str, sizeof (str));
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__close_nocancel (fd);
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if (s < 0)
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return 0;
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unsigned long int r = 0;
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for (ssize_t i = 0; i < s; i++)
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{
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if (str[i] == '\n')
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break;
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r *= 10;
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r += str[i] - '0';
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}
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return r;
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}
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enum malloc_thp_mode_t
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__malloc_thp_mode (void)
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{
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int fd = __open64_nocancel ("/sys/kernel/mm/transparent_hugepage/enabled",
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O_RDONLY);
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if (fd == -1)
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return malloc_thp_mode_not_supported;
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static const char mode_always[] = "[always] madvise never\n";
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static const char mode_madvise[] = "always [madvise] never\n";
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static const char mode_never[] = "always madvise [never]\n";
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char str[sizeof(mode_always)];
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ssize_t s = __read_nocancel (fd, str, sizeof (str));
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__close_nocancel (fd);
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if (s == sizeof (mode_always) - 1)
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{
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if (strcmp (str, mode_always) == 0)
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return malloc_thp_mode_always;
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else if (strcmp (str, mode_madvise) == 0)
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return malloc_thp_mode_madvise;
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else if (strcmp (str, mode_never) == 0)
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return malloc_thp_mode_never;
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}
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return malloc_thp_mode_not_supported;
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}
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static size_t
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malloc_default_hugepage_size (void)
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{
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int fd = __open64_nocancel ("/proc/meminfo", O_RDONLY);
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if (fd == -1)
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return 0;
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size_t hpsize = 0;
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char buf[512];
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off64_t off = 0;
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while (1)
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{
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ssize_t r = __pread64_nocancel (fd, buf, sizeof (buf) - 1, off);
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if (r < 0)
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break;
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buf[r] = '\0';
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/* If the tag is not found, read the last line again. */
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const char *s = strstr (buf, "Hugepagesize:");
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if (s == NULL)
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{
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char *nl = strrchr (buf, '\n');
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if (nl == NULL)
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break;
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off += (nl + 1) - buf;
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continue;
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}
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/* The default huge page size is in the form:
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Hugepagesize: NUMBER kB */
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s += sizeof ("Hugepagesize: ") - 1;
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for (int i = 0; (s[i] >= '0' && s[i] <= '9') || s[i] == ' '; i++)
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{
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if (s[i] == ' ')
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continue;
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hpsize *= 10;
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hpsize += s[i] - '0';
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}
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hpsize *= 1024;
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break;
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}
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__close_nocancel (fd);
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return hpsize;
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}
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static inline int
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hugepage_flags (size_t pagesize)
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{
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return MAP_HUGETLB | (__builtin_ctzll (pagesize) << MAP_HUGE_SHIFT);
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}
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void
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__malloc_hugepage_config (size_t requested, size_t *pagesize, int *flags)
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{
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*pagesize = 0;
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*flags = 0;
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if (requested == 0)
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{
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*pagesize = malloc_default_hugepage_size ();
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if (*pagesize != 0)
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*flags = hugepage_flags (*pagesize);
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return;
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}
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/* Each entry represents a supported huge page in the form of:
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hugepages-<size>kB. */
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int dirfd = __open64_nocancel ("/sys/kernel/mm/hugepages",
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O_RDONLY | O_DIRECTORY, 0);
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if (dirfd == -1)
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return;
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char buffer[1024];
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while (true)
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{
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#if !IS_IN(libc)
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# define __getdents64 getdents64
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#endif
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ssize_t ret = __getdents64 (dirfd, buffer, sizeof (buffer));
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if (ret == -1)
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break;
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else if (ret == 0)
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break;
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bool found = false;
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char *begin = buffer, *end = buffer + ret;
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while (begin != end)
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{
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unsigned short int d_reclen;
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memcpy (&d_reclen, begin + offsetof (struct dirent64, d_reclen),
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sizeof (d_reclen));
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const char *dname = begin + offsetof (struct dirent64, d_name);
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begin += d_reclen;
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if (dname[0] == '.'
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|| strncmp (dname, "hugepages-", sizeof ("hugepages-") - 1) != 0)
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continue;
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size_t hpsize = 0;
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const char *sizestr = dname + sizeof ("hugepages-") - 1;
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for (int i = 0; sizestr[i] >= '0' && sizestr[i] <= '9'; i++)
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{
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hpsize *= 10;
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hpsize += sizestr[i] - '0';
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}
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hpsize *= 1024;
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if (hpsize == requested)
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{
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*pagesize = hpsize;
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*flags = hugepage_flags (*pagesize);
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found = true;
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break;
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}
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}
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if (found)
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break;
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}
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__close_nocancel (dirfd);
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}
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