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| -rw-r--r-- | src/emman.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/src/emman.c b/src/emman.c new file mode 100644 index 0000000..0b511f9 --- /dev/null +++ b/src/emman.c @@ -0,0 +1,148 @@ +/* enable mremap on GNU/Linux */ +#ifdef __linux__ +# define _GNU_SOURCE +#endif + +/* enable the POSIX prototypes of mmap/munmap on Solaris */ +#ifdef __sun +# if __STDC_VERSION__ >= 199901L +# define _XOPEN_SOURCE 600 +# else +# define _XOPEN_SOURCE 500 +# endif +#endif + +#include "emman.h" + +#include <ecb.h> + +#include <string.h> + +#ifndef _WIN32 +# include <unistd.h> +#endif + +#if _POSIX_MAPPED_FILES > 0 +# define USE_MMAP 1 +# include <sys/mman.h> +# ifndef MAP_FAILED +# define MAP_FAILED ((void *)-1) +# endif +# ifndef MAP_ANONYMOUS +# ifdef MAP_ANON +# define MAP_ANONYMOUS MAP_ANON +# else +# undef USE_MMAP +# endif +# endif +# include <limits.h> +# ifndef PAGESIZE +static uint32_t pagesize; +# define BOOT_PAGESIZE if (!pagesize) pagesize = sysconf (_SC_PAGESIZE) +# define PAGESIZE pagesize +# else +# define BOOT_PAGESIZE +# endif +#else +# define PAGESIZE 1 +# define BOOT_PAGESIZE +#endif + +size_t +chunk_round (size_t size) +{ + BOOT_PAGESIZE; + + return (size + (PAGESIZE - 1)) & ~(size_t)(PAGESIZE - 1); +} + +size_t +chunk_fit (size_t header, size_t element_size, size_t max_increase) +{ + uint32_t fill, maximum_fill = 0; + size_t minimum_size; + + max_increase += header + element_size; + + BOOT_PAGESIZE; + + do + { + header += element_size; + + fill = (uint32_t)header & (PAGESIZE - 1); + + if (fill >= maximum_fill) + { + maximum_fill = fill + 16; /* size increase results in at least 16 bytes improvement */ + minimum_size = header; + } + } + while (header < max_increase); + + return minimum_size; +} + +void * +chunk_alloc (size_t size, int populate) +{ + #if USE_MMAP + void *ptr = MAP_FAILED; + + #ifdef MAP_POPULATE + if (populate & 1) + ptr = mmap (0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE, -1, 0); + #endif + + if (ptr == MAP_FAILED) + ptr = mmap (0, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + + if (ptr == MAP_FAILED) + return 0; + + return ptr; + #else + return malloc (size); + #endif +} + +void * +chunk_realloc (void *ptr, size_t old_size, size_t new_size) +{ + #if USE_MMAP + #ifdef MREMAP_MAYMOVE /* requires _GNU_SOURCE */ + void *ptr2 = mremap (ptr, old_size, new_size, MREMAP_MAYMOVE); + + if (ptr2 == MAP_FAILED) + return 0; + + return ptr2; + #else + void *ptr2 = chunk_alloc (new_size, 0); + + if (!ptr2) + return ptr2; + + /* TODO: prepopulate old_size pages instead of faulting them in */ + + memcpy (ptr2, ptr, old_size); + munmap (ptr, old_size); + return ptr2; + #endif + #else + return realloc (ptr, new_size); + #endif +} + +void +chunk_free (void *ptr, size_t size) +{ + #if USE_MMAP + /* we assume the OS never mmaps at address 0 */ + if (ptr) + munmap (ptr, size); + #else + return free (ptr); + #endif +} + |