mirror of git://sourceware.org/git/glibc.git
75 lines
2.2 KiB
C
75 lines
2.2 KiB
C
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/* Huge Page support. Linux implementation.
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Copyright (C) 2021 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 <malloc-hugepages.h>
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#include <not-cancel.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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