LCOV - code coverage report
Current view: directory - js/src/gc - Memory.cpp (source / functions) Found Hit Coverage
Test: app.info Lines: 37 32 86.5 %
Date: 2012-06-02 Functions: 5 4 80.0 %

       1                 : /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2                 :  * vim: set ts=8 sw=4 et tw=78:
       3                 :  *
       4                 :  * This Source Code Form is subject to the terms of the Mozilla Public
       5                 :  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
       6                 :  * You can obtain one at http://mozilla.org/MPL/2.0/. */
       7                 : 
       8                 : #include "jstypes.h"
       9                 : 
      10                 : #include "js/Utility.h"
      11                 : #include "gc/Memory.h"
      12                 : 
      13                 : namespace js {
      14                 : namespace gc {
      15                 : 
      16                 : #if defined(XP_WIN)
      17                 : #include "jswin.h"
      18                 : 
      19                 : static size_t AllocationGranularity = 0;
      20                 : 
      21                 : void
      22                 : InitMemorySubsystem()
      23                 : {
      24                 :     SYSTEM_INFO sysinfo;
      25                 :     GetSystemInfo(&sysinfo);
      26                 :     JS_OPT_ASSERT(sysinfo.dwPageSize == PageSize);
      27                 :     AllocationGranularity = sysinfo.dwAllocationGranularity;
      28                 : }
      29                 : 
      30                 : void *
      31                 : MapAlignedPages(size_t size, size_t alignment)
      32                 : {
      33                 :     JS_ASSERT(size >= alignment);
      34                 :     JS_ASSERT(size % alignment == 0);
      35                 :     JS_ASSERT(size % PageSize == 0);
      36                 :     JS_ASSERT(alignment % AllocationGranularity == 0);
      37                 : 
      38                 :     /* Special case: If we want allocation alignment, no further work is needed. */
      39                 :     if (alignment == AllocationGranularity) {
      40                 :         return VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
      41                 :     }
      42                 : 
      43                 :     /*
      44                 :      * Windows requires that there be a 1:1 mapping between VM allocation
      45                 :      * and deallocation operations.  Therefore, take care here to acquire the
      46                 :      * final result via one mapping operation.  This means unmapping any
      47                 :      * preliminary result that is not correctly aligned.
      48                 :      */
      49                 :     void *p = NULL;
      50                 :     while (!p) {
      51                 :         /*
      52                 :          * Over-allocate in order to map a memory region that is
      53                 :          * definitely large enough then deallocate and allocate again the
      54                 :          * correct sizee, within the over-sized mapping.
      55                 :          *
      56                 :          * Since we're going to unmap the whole thing anyway, the first
      57                 :          * mapping doesn't have to commit pages.
      58                 :          */
      59                 :         p = VirtualAlloc(NULL, size * 2, MEM_RESERVE, PAGE_READWRITE);
      60                 :         if (!p)
      61                 :             return NULL;
      62                 :         void *chunkStart = (void *)(uintptr_t(p) + (alignment - (uintptr_t(p) % alignment)));
      63                 :         UnmapPages(p, size * 2);
      64                 :         p = VirtualAlloc(chunkStart, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
      65                 : 
      66                 :         /* Failure here indicates a race with another thread, so try again. */
      67                 :     }
      68                 : 
      69                 :     JS_ASSERT(uintptr_t(p) % alignment == 0);
      70                 :     return p;
      71                 : }
      72                 : 
      73                 : void
      74                 : UnmapPages(void *p, size_t size)
      75                 : {
      76                 :     JS_ALWAYS_TRUE(VirtualFree(p, 0, MEM_RELEASE));
      77                 : }
      78                 : 
      79                 : bool
      80                 : MarkPagesUnused(void *p, size_t size)
      81                 : {
      82                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
      83                 :     LPVOID p2 = VirtualAlloc(p, size, MEM_RESET, PAGE_READWRITE);
      84                 :     return p2 == p;
      85                 : }
      86                 : 
      87                 : bool
      88                 : MarkPagesInUse(void *p, size_t size)
      89                 : {
      90                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
      91                 :     return true;
      92                 : }
      93                 : 
      94                 : #elif defined(XP_OS2)
      95                 : 
      96                 : #define INCL_DOSMEMMGR
      97                 : #include <os2.h>
      98                 : 
      99                 : #define JS_GC_HAS_MAP_ALIGN 1
     100                 : #define OS2_MAX_RECURSIONS  16
     101                 : 
     102                 : void
     103                 : InitMemorySubsystem()
     104                 : {
     105                 : }
     106                 : 
     107                 : void
     108                 : UnmapPages(void *addr, size_t size)
     109                 : {
     110                 :     if (!DosFreeMem(addr))
     111                 :         return;
     112                 : 
     113                 :     /*
     114                 :      * If DosFreeMem() failed, 'addr' is probably part of an "expensive"
     115                 :      * allocation, so calculate the base address and try again.
     116                 :      */
     117                 :     unsigned long cb = 2 * size;
     118                 :     unsigned long flags;
     119                 :     if (DosQueryMem(addr, &cb, &flags) || cb < size)
     120                 :         return;
     121                 : 
     122                 :     uintptr_t base = reinterpret_cast<uintptr_t>(addr) - ((2 * size) - cb);
     123                 :     DosFreeMem(reinterpret_cast<void*>(base));
     124                 : 
     125                 :     return;
     126                 : }
     127                 : 
     128                 : static void *
     129                 : MapAlignedPagesRecursively(size_t size, size_t alignment, int& recursions)
     130                 : {
     131                 :     if (++recursions >= OS2_MAX_RECURSIONS)
     132                 :         return NULL;
     133                 : 
     134                 :     void *tmp;
     135                 :     if (DosAllocMem(&tmp, size,
     136                 :                     OBJ_ANY | PAG_COMMIT | PAG_READ | PAG_WRITE)) {
     137                 :         JS_ALWAYS_TRUE(DosAllocMem(&tmp, size,
     138                 :                                    PAG_COMMIT | PAG_READ | PAG_WRITE) == 0);
     139                 :     }
     140                 :     size_t offset = reinterpret_cast<uintptr_t>(tmp) & (alignment - 1);
     141                 :     if (!offset)
     142                 :         return tmp;
     143                 : 
     144                 :     /*
     145                 :      * If there are 'filler' bytes of free space above 'tmp', free 'tmp',
     146                 :      * then reallocate it as a 'filler'-sized block;  assuming we're not
     147                 :      * in a race with another thread, the next recursion should succeed.
     148                 :      */
     149                 :     size_t filler = size + alignment - offset;
     150                 :     unsigned long cb = filler;
     151                 :     unsigned long flags = 0;
     152                 :     unsigned long rc = DosQueryMem(&(static_cast<char*>(tmp))[size],
     153                 :                                    &cb, &flags);
     154                 :     if (!rc && (flags & PAG_FREE) && cb >= filler) {
     155                 :         UnmapPages(tmp, 0);
     156                 :         if (DosAllocMem(&tmp, filler,
     157                 :                         OBJ_ANY | PAG_COMMIT | PAG_READ | PAG_WRITE)) {
     158                 :             JS_ALWAYS_TRUE(DosAllocMem(&tmp, filler,
     159                 :                                        PAG_COMMIT | PAG_READ | PAG_WRITE) == 0);
     160                 :         }
     161                 :     }
     162                 : 
     163                 :     void *p = MapAlignedPagesRecursively(size, alignment, recursions);
     164                 :     UnmapPages(tmp, 0);
     165                 : 
     166                 :     return p;
     167                 : }
     168                 : 
     169                 : void *
     170                 : MapAlignedPages(size_t size, size_t alignment)
     171                 : {
     172                 :     JS_ASSERT(size >= alignment);
     173                 :     JS_ASSERT(size % alignment == 0);
     174                 :     JS_ASSERT(size % PageSize == 0);
     175                 :     JS_ASSERT(alignment % PageSize == 0);
     176                 : 
     177                 :     int recursions = -1;
     178                 : 
     179                 :     /*
     180                 :      * Make up to OS2_MAX_RECURSIONS attempts to get an aligned block
     181                 :      * of the right size by recursively allocating blocks of unaligned
     182                 :      * free memory until only an aligned allocation is possible.
     183                 :      */
     184                 :     void *p = MapAlignedPagesRecursively(size, alignment, recursions);
     185                 :     if (p)
     186                 :         return p;
     187                 : 
     188                 :     /*
     189                 :      * If memory is heavily fragmented, the recursive strategy may fail;
     190                 :      * instead, use the "expensive" strategy:  allocate twice as much
     191                 :      * as requested and return an aligned address within this block.
     192                 :      */
     193                 :     if (DosAllocMem(&p, 2 * size,
     194                 :                     OBJ_ANY | PAG_COMMIT | PAG_READ | PAG_WRITE)) {
     195                 :         JS_ALWAYS_TRUE(DosAllocMem(&p, 2 * size,
     196                 :                                    PAG_COMMIT | PAG_READ | PAG_WRITE) == 0);
     197                 :     }
     198                 : 
     199                 :     uintptr_t addr = reinterpret_cast<uintptr_t>(p);
     200                 :     addr = (addr + (alignment - 1)) & ~(alignment - 1);
     201                 : 
     202                 :     return reinterpret_cast<void *>(addr);
     203                 : }
     204                 : 
     205                 : bool
     206                 : MarkPagesUnused(void *p, size_t size)
     207                 : {
     208                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     209                 :     return true;
     210                 : }
     211                 : 
     212                 : bool
     213                 : MarkPagesInUse(void *p, size_t size)
     214                 : {
     215                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     216                 :     return true;
     217                 : }
     218                 : 
     219                 : #elif defined(SOLARIS)
     220                 : 
     221                 : #include <sys/mman.h>
     222                 : #include <unistd.h>
     223                 : 
     224                 : #ifndef MAP_NOSYNC
     225                 : # define MAP_NOSYNC 0
     226                 : #endif
     227                 : 
     228                 : void
     229                 : InitMemorySubsystem()
     230                 : {
     231                 : }
     232                 : 
     233                 : void *
     234                 : MapAlignedPages(size_t size, size_t alignment)
     235                 : {
     236                 :     JS_ASSERT(size >= alignment);
     237                 :     JS_ASSERT(size % alignment == 0);
     238                 :     JS_ASSERT(size % PageSize == 0);
     239                 :     JS_ASSERT(alignment % PageSize == 0);
     240                 : 
     241                 :     int prot = PROT_READ | PROT_WRITE;
     242                 :     int flags = MAP_PRIVATE | MAP_ANON | MAP_ALIGN | MAP_NOSYNC;
     243                 : 
     244                 :     void *p = mmap((caddr_t)alignment, size, prot, flags, -1, 0);
     245                 :     if (p == MAP_FAILED)
     246                 :         return NULL;
     247                 :     return p;
     248                 : }
     249                 : 
     250                 : void
     251                 : UnmapPages(void *p, size_t size)
     252                 : {
     253                 :     JS_ALWAYS_TRUE(0 == munmap((caddr_t)p, size));
     254                 : }
     255                 : 
     256                 : bool
     257                 : MarkPagesUnused(void *p, size_t size)
     258                 : {
     259                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     260                 :     return true;
     261                 : }
     262                 : 
     263                 : bool
     264                 : MarkPagesInUse(void *p, size_t size)
     265                 : {
     266                 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     267                 :     return true;
     268                 : }
     269                 : 
     270                 : #elif defined(XP_UNIX) || defined(XP_MACOSX) || defined(DARWIN)
     271                 : 
     272                 : #include <sys/mman.h>
     273                 : #include <unistd.h>
     274                 : 
     275                 : void
     276           19811 : InitMemorySubsystem()
     277                 : {
     278           19811 :     JS_OPT_ASSERT(size_t(sysconf(_SC_PAGESIZE)) == PageSize);
     279           19811 : }
     280                 : 
     281                 : void *
     282           43620 : MapAlignedPages(size_t size, size_t alignment)
     283                 : {
     284           43620 :     JS_ASSERT(size >= alignment);
     285           43620 :     JS_ASSERT(size % alignment == 0);
     286           43620 :     JS_ASSERT(size % PageSize == 0);
     287           43620 :     JS_ASSERT(alignment % PageSize == 0);
     288                 : 
     289           43620 :     int prot = PROT_READ | PROT_WRITE;
     290           43620 :     int flags = MAP_PRIVATE | MAP_ANON;
     291                 : 
     292                 :     /* Special case: If we want page alignment, no further work is needed. */
     293           43620 :     if (alignment == PageSize) {
     294               0 :         return mmap(NULL, size, prot, flags, -1, 0);
     295                 :     }
     296                 : 
     297                 :     /* Overallocate and unmap the region's edges. */
     298           43620 :     size_t reqSize = JS_MIN(size + 2 * alignment, 2 * size);
     299           43620 :     void *region = mmap(NULL, reqSize, prot, flags, -1, 0);
     300           43620 :     if (region == MAP_FAILED)
     301               0 :         return NULL;
     302                 : 
     303           43620 :     uintptr_t regionEnd = uintptr_t(region) + reqSize;
     304           43620 :     uintptr_t offset = uintptr_t(region) % alignment;
     305           43620 :     JS_ASSERT(offset < reqSize - size);
     306                 : 
     307           43620 :     void *front = (void *)(uintptr_t(region) + (alignment - offset));
     308           43620 :     void *end = (void *)(uintptr_t(front) + size);
     309           43620 :     if (front != region)
     310           43620 :         JS_ALWAYS_TRUE(0 == munmap(region, alignment - offset));
     311           43620 :     if (uintptr_t(end) != regionEnd)
     312           20051 :         JS_ALWAYS_TRUE(0 == munmap(end, regionEnd - uintptr_t(end)));
     313                 : 
     314           43620 :     JS_ASSERT(uintptr_t(front) % alignment == 0);
     315           43620 :     return front;
     316                 : }
     317                 : 
     318                 : void
     319           43616 : UnmapPages(void *p, size_t size)
     320                 : {
     321           43616 :     JS_ALWAYS_TRUE(0 == munmap(p, size));
     322           43616 : }
     323                 : 
     324                 : bool
     325            4140 : MarkPagesUnused(void *p, size_t size)
     326                 : {
     327            4140 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     328            4140 :     int result = madvise(p, size, MADV_DONTNEED);
     329            4140 :     return result != -1;
     330                 : }
     331                 : 
     332                 : bool
     333               0 : MarkPagesInUse(void *p, size_t size)
     334                 : {
     335               0 :     JS_ASSERT(uintptr_t(p) % PageSize == 0);
     336               0 :     return true;
     337                 : }
     338                 : 
     339                 : #else
     340                 : #error "Memory mapping functions are not defined for your OS."
     341                 : #endif
     342                 : 
     343                 : } /* namespace gc */
     344                 : } /* namespace js */

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