libgomp/config/linux/allocator.c

   1 /* Copyright (C) 2022-2024 Free Software Foundation, Inc.
   2    Contributed by Jakub Jelinek <jakub@redhat.com>.
   3
   4    This file is part of the GNU Offloading and Multi Processing Library
   5    (libgomp).
   6
   7    Libgomp is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  14    FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15    more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26 /* This file contains wrappers for the system allocation routines.  Most
  27    places in the OpenMP API do not make any provision for failure, so in
  28    general we cannot allow memory allocation to fail.  */
  29
  30 #define _GNU_SOURCE
  31 #include "libgomp.h"
  32 #if defined(PLUGIN_SUPPORT) && defined(LIBGOMP_USE_PTHREADS)
  33 #define LIBGOMP_USE_MEMKIND
  34 #define LIBGOMP_USE_LIBNUMA
  35 #endif
  36
  37 /* Implement malloc routines that can handle pinned memory on Linux.
  38
  39    It's possible to use mlock on any heap memory, but using munlock is
  40    problematic if there are multiple pinned allocations on the same page.
  41    Tracking all that manually would be possible, but adds overhead. This may
  42    be worth it if there are a lot of small allocations getting pinned, but
  43    this seems less likely in a HPC application.
  44
  45    Instead we optimize for large pinned allocations, and use mmap to ensure
  46    that two pinned allocations don't share the same page.  This also means
  47    that large allocations don't pin extra pages by being poorly aligned.  */
  48
  49 #define _GNU_SOURCE
  50 #include <sys/mman.h>
  51 #include <string.h>
  52 #include "libgomp.h"
  53 #ifdef HAVE_INTTYPES_H
  54 # include <inttypes.h>  /* For PRIu64.  */
  55 #endif
  56
  57 static void *
  58 linux_memspace_alloc (omp_memspace_handle_t memspace, size_t size, int pin)
  59 {
  60   (void)memspace;
  61
  62   if (pin)
  63     {
  64       /* Note that mmap always returns zeroed memory and is therefore also a
  65          suitable implementation of calloc.  */
  66       void *addr = mmap (NULL, size, PROT_READ | PROT_WRITE,
  67                          MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
  68       if (addr == MAP_FAILED)
  69         return NULL;
  70
  71       if (mlock (addr, size))
  72         {
  73 #ifdef HAVE_INTTYPES_H
  74           gomp_debug (0, "libgomp: failed to pin %"PRIu64" bytes of"
  75                       " memory (ulimit too low?)\n", (uint64_t) size);
  76 #else
  77           gomp_debug (0, "libgomp: failed to pin %lu bytes of"
  78                       " memory (ulimit too low?)\n", (unsigned long) size);
  79 #endif
  80           munmap (addr, size);
  81           return NULL;
  82         }
  83
  84       return addr;
  85     }
  86   else
  87     return malloc (size);
  88 }
  89
  90 static void *
  91 linux_memspace_calloc (omp_memspace_handle_t memspace, size_t size, int pin)
  92 {
  93   if (pin)
  94     return linux_memspace_alloc (memspace, size, pin);
  95   else
  96     return calloc (1, size);
  97 }
  98
  99 static void
 100 linux_memspace_free (omp_memspace_handle_t memspace, void *addr, size_t size,
 101                      int pin)
 102 {
 103   (void)memspace;
 104
 105   if (pin)
 106     munmap (addr, size);
 107   else
 108     free (addr);
 109 }
 110
 111 static void *
 112 linux_memspace_realloc (omp_memspace_handle_t memspace, void *addr,
 113                         size_t oldsize, size_t size, int oldpin, int pin)
 114 {
 115   if (oldpin && pin)
 116     {
 117       void *newaddr = mremap (addr, oldsize, size, MREMAP_MAYMOVE);
 118       if (newaddr == MAP_FAILED)
 119         return NULL;
 120
 121       return newaddr;
 122     }
 123   else if (oldpin || pin)
 124     {
 125       void *newaddr = linux_memspace_alloc (memspace, size, pin);
 126       if (newaddr)
 127         {
 128           memcpy (newaddr, addr, oldsize < size ? oldsize : size);
 129           linux_memspace_free (memspace, addr, oldsize, oldpin);
 130         }
 131
 132       return newaddr;
 133     }
 134   else
 135     return realloc (addr, size);
 136 }
 137
 138 static int
 139 linux_memspace_validate (omp_memspace_handle_t, unsigned, int)
 140 {
 141   /* Everything should be accepted on Linux, including pinning.  */
 142   return 1;
 143 }
 144
 145 #define MEMSPACE_ALLOC(MEMSPACE, SIZE, PIN) \
 146   linux_memspace_alloc (MEMSPACE, SIZE, PIN)
 147 #define MEMSPACE_CALLOC(MEMSPACE, SIZE, PIN) \
 148   linux_memspace_calloc (MEMSPACE, SIZE, PIN)
 149 #define MEMSPACE_REALLOC(MEMSPACE, ADDR, OLDSIZE, SIZE, OLDPIN, PIN) \
 150   linux_memspace_realloc (MEMSPACE, ADDR, OLDSIZE, SIZE, OLDPIN, PIN)
 151 #define MEMSPACE_FREE(MEMSPACE, ADDR, SIZE, PIN) \
 152   linux_memspace_free (MEMSPACE, ADDR, SIZE, PIN)
 153 #define MEMSPACE_VALIDATE(MEMSPACE, ACCESS, PIN) \
 154   linux_memspace_validate (MEMSPACE, ACCESS, PIN)
 155
 156 #include "../../allocator.c"