diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/chunk_mmap.c | 10 | ||||
| -rw-r--r-- | src/jemalloc.c | 1 | ||||
| -rw-r--r-- | src/pages.c | 116 |
3 files changed, 102 insertions, 25 deletions
diff --git a/src/chunk_mmap.c b/src/chunk_mmap.c index e2e66bc..f95ae75 100644 --- a/src/chunk_mmap.c +++ b/src/chunk_mmap.c @@ -16,18 +16,16 @@ chunk_alloc_mmap_slow(size_t size, size_t alignment, bool *zero, bool *commit) do { void *pages; size_t leadsize; - pages = pages_map(NULL, alloc_size); + pages = pages_map(NULL, alloc_size, commit); if (pages == NULL) return (NULL); leadsize = ALIGNMENT_CEILING((uintptr_t)pages, alignment) - (uintptr_t)pages; - ret = pages_trim(pages, alloc_size, leadsize, size); + ret = pages_trim(pages, alloc_size, leadsize, size, commit); } while (ret == NULL); assert(ret != NULL); *zero = true; - if (!*commit) - *commit = pages_decommit(ret, size); return (ret); } @@ -54,7 +52,7 @@ chunk_alloc_mmap(void *new_addr, size_t size, size_t alignment, bool *zero, assert(alignment != 0); assert((alignment & chunksize_mask) == 0); - ret = pages_map(new_addr, size); + ret = pages_map(new_addr, size, commit); if (ret == NULL || ret == new_addr) return (ret); assert(new_addr == NULL); @@ -66,8 +64,6 @@ chunk_alloc_mmap(void *new_addr, size_t size, size_t alignment, bool *zero, assert(ret != NULL); *zero = true; - if (!*commit) - *commit = pages_decommit(ret, size); return (ret); } diff --git a/src/jemalloc.c b/src/jemalloc.c index cd97ea1..1a26a44 100644 --- a/src/jemalloc.c +++ b/src/jemalloc.c @@ -1272,6 +1272,7 @@ malloc_init_hard_a0_locked(tsd_t *tsd) abort(); } } + pages_boot(); if (base_boot()) return (true); if (chunk_boot()) diff --git a/src/pages.c b/src/pages.c index 83a167f..2a9b7e3 100644 --- a/src/pages.c +++ b/src/pages.c @@ -1,29 +1,49 @@ #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) +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_COMMIT | MEM_RESERVE, + 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. */ - ret = mmap(addr, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, - -1, 0); + { + 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) @@ -67,7 +87,8 @@ pages_unmap(void *addr, size_t size) } void * -pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size) +pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size, + bool *commit) { void *ret = (void *)((uintptr_t)addr + leadsize); @@ -77,7 +98,7 @@ pages_trim(void *addr, size_t alloc_size, size_t leadsize, size_t size) void *new_addr; pages_unmap(addr, alloc_size); - new_addr = pages_map(ret, size); + new_addr = pages_map(ret, size, commit); if (new_addr == ret) return (ret); if (new_addr) @@ -101,17 +122,17 @@ static bool pages_commit_impl(void *addr, size_t size, bool commit) { -#ifndef _WIN32 - /* - * The following decommit/commit implementation is functional, but - * always disabled because it doesn't add value beyong improved - * debugging (at the cost of extra system calls) on systems that - * overcommit. - */ - if (false) { - int prot = commit ? (PROT_READ | PROT_WRITE) : PROT_NONE; - void *result = mmap(addr, size, prot, MAP_PRIVATE | MAP_ANON | - MAP_FIXED, -1, 0); + 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) { @@ -125,7 +146,6 @@ pages_commit_impl(void *addr, size_t size, bool commit) return (false); } #endif - return (true); } bool @@ -171,3 +191,63 @@ pages_purge(void *addr, size_t size) return (unzeroed); } +#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 +static bool +os_overcommits_proc(void) +{ + int fd; + char buf[1]; + ssize_t nread; + + fd = open("/proc/sys/vm/overcommit_memory", O_RDONLY); + if (fd == -1) + return (false); /* Error. */ + + nread = read(fd, &buf, sizeof(buf)); + 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 +} |