1#define JEMALLOC_PAGES_C_ 2#include "jemalloc/internal/jemalloc_internal.h" 3 4/******************************************************************************/ 5/* Defines/includes needed for special android code. */ 6 7#if defined(__ANDROID__) 8#include <sys/prctl.h> 9 10/* Definitions of prctl arguments to set a vma name in Android kernels. */ 11#define ANDROID_PR_SET_VMA 0x53564d41 12#define ANDROID_PR_SET_VMA_ANON_NAME 0 13#endif 14 15/******************************************************************************/ 16 17void * 18pages_map(void *addr, size_t size) 19{ 20 void *ret; 21 22 assert(size != 0); 23 24#ifdef _WIN32 25 /* 26 * If VirtualAlloc can't allocate at the given address when one is 27 * given, it fails and returns NULL. 28 */ 29 ret = VirtualAlloc(addr, size, MEM_COMMIT | MEM_RESERVE, 30 PAGE_READWRITE); 31#else 32 /* 33 * We don't use MAP_FIXED here, because it can cause the *replacement* 34 * of existing mappings, and we only want to create new mappings. 35 */ 36 ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, 37 -1, 0); 38 assert(ret != NULL); 39 40 if (ret == MAP_FAILED) 41 ret = NULL; 42 else if (addr != NULL && ret != addr) { 43 /* 44 * We succeeded in mapping memory, but not in the right place. 45 */ 46 pages_unmap(ret, size); 47 ret = NULL; 48 } 49#endif 50#if defined(__ANDROID__) 51 if (ret != NULL) { 52 /* Name this memory as being used by libc */ 53 prctl(ANDROID_PR_SET_VMA, ANDROID_PR_SET_VMA_ANON_NAME, ret, 54 size, "libc_malloc"); 55 } 56#endif 57 assert(ret == NULL || (addr == NULL && ret != addr) 58 || (addr != NULL && ret == addr)); 59 return (ret); 60} 61 62void 63pages_unmap(void *addr, size_t size) 64{ 65 66#ifdef _WIN32 67 if (VirtualFree(addr, 0, MEM_RELEASE) == 0) 68#else 69 if (munmap(addr, size) == -1) 70#endif 71 { 72 char buf[BUFERROR_BUF]; 73 74 buferror(get_errno(), buf, sizeof(buf)); 75 malloc_printf("<jemalloc>: Error in " 76#ifdef _WIN32 77 "VirtualFree" 78#else 79 "munmap" 80#endif 81 "(): %s\n", buf); 82 if (opt_abort) 83 abort(); 84 } 85} 86 87void * 88pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size) 89{ 90 void *ret = (void *)((uintptr_t)addr + leadsize); 91 92 assert(alloc_size >= leadsize + size); 93#ifdef _WIN32 94 { 95 void *new_addr; 96 97 pages_unmap(addr, alloc_size); 98 new_addr = pages_map(ret, size); 99 if (new_addr == ret) 100 return (ret); 101 if (new_addr) 102 pages_unmap(new_addr, size); 103 return (NULL); 104 } 105#else 106 { 107 size_t trailsize = alloc_size - leadsize - size; 108 109 if (leadsize != 0) 110 pages_unmap(addr, leadsize); 111 if (trailsize != 0) 112 pages_unmap((void *)((uintptr_t)ret + size), trailsize); 113 return (ret); 114 } 115#endif 116} 117 118static bool 119pages_commit_impl(void *addr, size_t size, bool commit) 120{ 121 122#ifndef _WIN32 123 /* 124 * The following decommit/commit implementation is functional, but 125 * always disabled because it doesn't add value beyong improved 126 * debugging (at the cost of extra system calls) on systems that 127 * overcommit. 128 */ 129 if (false) { 130 int prot = commit ? (PROT_READ | PROT_WRITE) : PROT_NONE; 131 void *result = mmap(addr, size, prot, MAP_PRIVATE | MAP_ANON | 132 MAP_FIXED, -1, 0); 133 if (result == MAP_FAILED) 134 return (true); 135 if (result != addr) { 136 /* 137 * We succeeded in mapping memory, but not in the right 138 * place. 139 */ 140 pages_unmap(result, size); 141 return (true); 142 } 143 return (false); 144 } 145#endif 146 return (true); 147} 148 149bool 150pages_commit(void *addr, size_t size) 151{ 152 153 return (pages_commit_impl(addr, size, true)); 154} 155 156bool 157pages_decommit(void *addr, size_t size) 158{ 159 160 return (pages_commit_impl(addr, size, false)); 161} 162 163bool 164pages_purge(void *addr, size_t size) 165{ 166 bool unzeroed; 167 168#ifdef _WIN32 169 VirtualAlloc(addr, size, MEM_RESET, PAGE_READWRITE); 170 unzeroed = true; 171#elif defined(JEMALLOC_HAVE_MADVISE) 172# ifdef JEMALLOC_PURGE_MADVISE_DONTNEED 173# define JEMALLOC_MADV_PURGE MADV_DONTNEED 174# define JEMALLOC_MADV_ZEROS true 175# elif defined(JEMALLOC_PURGE_MADVISE_FREE) 176# define JEMALLOC_MADV_PURGE MADV_FREE 177# define JEMALLOC_MADV_ZEROS false 178# else 179# error "No madvise(2) flag defined for purging unused dirty pages." 180# endif 181 int err = madvise(addr, size, JEMALLOC_MADV_PURGE); 182 unzeroed = (!JEMALLOC_MADV_ZEROS || err != 0); 183# undef JEMALLOC_MADV_PURGE 184# undef JEMALLOC_MADV_ZEROS 185#else 186 /* Last resort no-op. */ 187 unzeroed = true; 188#endif 189 return (unzeroed); 190} 191 192