diff options
Diffstat (limited to 'deps/jemalloc/src/pages.c')
| -rw-r--r-- | deps/jemalloc/src/pages.c | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/deps/jemalloc/src/pages.c b/deps/jemalloc/src/pages.c new file mode 100644 index 0000000..5f0c966 --- /dev/null +++ b/deps/jemalloc/src/pages.c @@ -0,0 +1,302 @@ +#define JEMALLOC_PAGES_C_ +#include "jemalloc/internal/jemalloc_internal.h" + +#ifdef JEMALLOC_SYSCTL_VM_OVERCOMMIT +#include <sys/sysctl.h> +#endif + +/******************************************************************************/ +/* Data. */ + +#ifndef _WIN32 +# define PAGES_PROT_COMMIT (PROT_READ | PROT_WRITE) +# define PAGES_PROT_DECOMMIT (PROT_NONE) +static int mmap_flags; +#endif +static bool os_overcommits; + +/******************************************************************************/ + +void * +pages_map(void *addr, size_t size, bool *commit) +{ + void *ret; + + assert(size != 0); + + if (os_overcommits) + *commit = true; + +#ifdef _WIN32 + /* + * If VirtualAlloc can't allocate at the given address when one is + * given, it fails and returns NULL. + */ + ret = VirtualAlloc(addr, size, MEM_RESERVE | (*commit ? MEM_COMMIT : 0), + PAGE_READWRITE); +#else + /* + * We don't use MAP_FIXED here, because it can cause the *replacement* + * of existing mappings, and we only want to create new mappings. + */ + { + int prot = *commit ? PAGES_PROT_COMMIT : PAGES_PROT_DECOMMIT; + + ret = mmap(addr, size, prot, mmap_flags, -1, 0); + } + assert(ret != NULL); + + if (ret == MAP_FAILED) + ret = NULL; + else if (addr != NULL && ret != addr) { + /* + * We succeeded in mapping memory, but not in the right place. + */ + pages_unmap(ret, size); + ret = NULL; + } +#endif + assert(ret == NULL || (addr == NULL && ret != addr) + || (addr != NULL && ret == addr)); + return (ret); +} + +void +pages_unmap(void *addr, size_t size) +{ + +#ifdef _WIN32 + if (VirtualFree(addr, 0, MEM_RELEASE) == 0) +#else + if (munmap(addr, size) == -1) +#endif + { + char buf[BUFERROR_BUF]; + + buferror(get_errno(), buf, sizeof(buf)); + malloc_printf("<jemalloc>: Error in " +#ifdef _WIN32 + "VirtualFree" +#else + "munmap" +#endif + "(): %s\n", buf); + if (opt_abort) + abort(); + } +} + +void * +pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size, + bool *commit) +{ + void *ret = (void *)((uintptr_t)addr + leadsize); + + assert(alloc_size >= leadsize + size); +#ifdef _WIN32 + { + void *new_addr; + + pages_unmap(addr, alloc_size); + new_addr = pages_map(ret, size, commit); + if (new_addr == ret) + return (ret); + if (new_addr) + pages_unmap(new_addr, size); + return (NULL); + } +#else + { + size_t trailsize = alloc_size - leadsize - size; + + if (leadsize != 0) + pages_unmap(addr, leadsize); + if (trailsize != 0) + pages_unmap((void *)((uintptr_t)ret + size), trailsize); + return (ret); + } +#endif +} + +static bool +pages_commit_impl(void *addr, size_t size, bool commit) +{ + + if (os_overcommits) + return (true); + +#ifdef _WIN32 + return (commit ? (addr != VirtualAlloc(addr, size, MEM_COMMIT, + PAGE_READWRITE)) : (!VirtualFree(addr, size, MEM_DECOMMIT))); +#else + { + int prot = commit ? PAGES_PROT_COMMIT : PAGES_PROT_DECOMMIT; + void *result = mmap(addr, size, prot, mmap_flags | MAP_FIXED, + -1, 0); + if (result == MAP_FAILED) + return (true); + if (result != addr) { + /* + * We succeeded in mapping memory, but not in the right + * place. + */ + pages_unmap(result, size); + return (true); + } + return (false); + } +#endif +} + +bool +pages_commit(void *addr, size_t size) +{ + + return (pages_commit_impl(addr, size, true)); +} + +bool +pages_decommit(void *addr, size_t size) +{ + + return (pages_commit_impl(addr, size, false)); +} + +bool +pages_purge(void *addr, size_t size) +{ + bool unzeroed; + +#ifdef _WIN32 + VirtualAlloc(addr, size, MEM_RESET, PAGE_READWRITE); + unzeroed = true; +#elif (defined(JEMALLOC_PURGE_MADVISE_FREE) || \ + defined(JEMALLOC_PURGE_MADVISE_DONTNEED)) +# if defined(JEMALLOC_PURGE_MADVISE_FREE) +# define JEMALLOC_MADV_PURGE MADV_FREE +# define JEMALLOC_MADV_ZEROS false +# elif defined(JEMALLOC_PURGE_MADVISE_DONTNEED) +# define JEMALLOC_MADV_PURGE MADV_DONTNEED +# define JEMALLOC_MADV_ZEROS true +# else +# error No madvise(2) flag defined for purging unused dirty pages +# endif + int err = madvise(addr, size, JEMALLOC_MADV_PURGE); + unzeroed = (!JEMALLOC_MADV_ZEROS || err != 0); +# undef JEMALLOC_MADV_PURGE +# undef JEMALLOC_MADV_ZEROS +#else + /* Last resort no-op. */ + unzeroed = true; +#endif + return (unzeroed); +} + +bool +pages_huge(void *addr, size_t size) +{ + + assert(PAGE_ADDR2BASE(addr) == addr); + assert(PAGE_CEILING(size) == size); + +#ifdef JEMALLOC_THP + return (madvise(addr, size, MADV_HUGEPAGE) != 0); +#else + return (false); +#endif +} + +bool +pages_nohuge(void *addr, size_t size) +{ + + assert(PAGE_ADDR2BASE(addr) == addr); + assert(PAGE_CEILING(size) == size); + +#ifdef JEMALLOC_THP + return (madvise(addr, size, MADV_NOHUGEPAGE) != 0); +#else + return (false); +#endif +} + +#ifdef JEMALLOC_SYSCTL_VM_OVERCOMMIT +static bool +os_overcommits_sysctl(void) +{ + int vm_overcommit; + size_t sz; + + sz = sizeof(vm_overcommit); + if (sysctlbyname("vm.overcommit", &vm_overcommit, &sz, NULL, 0) != 0) + return (false); /* Error. */ + + return ((vm_overcommit & 0x3) == 0); +} +#endif + +#ifdef JEMALLOC_PROC_SYS_VM_OVERCOMMIT_MEMORY +/* + * Use syscall(2) rather than {open,read,close}(2) when possible to avoid + * reentry during bootstrapping if another library has interposed system call + * wrappers. + */ +static bool +os_overcommits_proc(void) +{ + int fd; + char buf[1]; + ssize_t nread; + +#if defined(JEMALLOC_USE_SYSCALL) && defined(SYS_open) + fd = (int)syscall(SYS_open, "/proc/sys/vm/overcommit_memory", O_RDONLY); +#else + fd = open("/proc/sys/vm/overcommit_memory", O_RDONLY); +#endif + if (fd == -1) + return (false); /* Error. */ + +#if defined(JEMALLOC_USE_SYSCALL) && defined(SYS_read) + nread = (ssize_t)syscall(SYS_read, fd, &buf, sizeof(buf)); +#else + nread = read(fd, &buf, sizeof(buf)); +#endif + +#if defined(JEMALLOC_USE_SYSCALL) && defined(SYS_close) + syscall(SYS_close, fd); +#else + close(fd); +#endif + + if (nread < 1) + return (false); /* Error. */ + /* + * /proc/sys/vm/overcommit_memory meanings: + * 0: Heuristic overcommit. + * 1: Always overcommit. + * 2: Never overcommit. + */ + return (buf[0] == '0' || buf[0] == '1'); +} +#endif + +void +pages_boot(void) +{ + +#ifndef _WIN32 + mmap_flags = MAP_PRIVATE | MAP_ANON; +#endif + +#ifdef JEMALLOC_SYSCTL_VM_OVERCOMMIT + os_overcommits = os_overcommits_sysctl(); +#elif defined(JEMALLOC_PROC_SYS_VM_OVERCOMMIT_MEMORY) + os_overcommits = os_overcommits_proc(); +# ifdef MAP_NORESERVE + if (os_overcommits) + mmap_flags |= MAP_NORESERVE; +# endif +#else + os_overcommits = false; +#endif +} |