diff options
Diffstat (limited to 'sysdep/unix/alloc.c')
| -rw-r--r-- | sysdep/unix/alloc.c | 43 |
1 files changed, 41 insertions, 2 deletions
diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c index 4c9d5eb5..4ae1a9db 100644 --- a/sysdep/unix/alloc.c +++ b/sysdep/unix/alloc.c @@ -11,6 +11,8 @@ #include <stdlib.h> #include <unistd.h> +#include <stdatomic.h> +#include <errno.h> #ifdef HAVE_MMAP #include <sys/mman.h> @@ -19,6 +21,13 @@ long page_size = 0; _Bool alloc_multipage = 0; +static _Atomic int global_page_list_not_empty; +static list global_page_list; +static _Atomic int global_page_spinlock; + +#define GLOBAL_PAGE_SPIN_LOCK for (int v = 0; !atomic_compare_exchange_weak_explicit(&global_page_spinlock, &v, 1, memory_order_acq_rel, memory_order_acquire); v = 0) +#define GLOBAL_PAGE_SPIN_UNLOCK do { int v = 1; ASSERT_DIE(atomic_compare_exchange_strong_explicit(&global_page_spinlock, &v, 0, memory_order_acq_rel, memory_order_acquire)); } while (0) + #ifdef HAVE_MMAP static _Bool use_fake = 0; #else @@ -28,12 +37,14 @@ static _Bool use_fake = 1; void resource_sys_init(void) { #ifdef HAVE_MMAP + init_list(&global_page_list); + if (!(page_size = sysconf(_SC_PAGESIZE))) die("System page size must be non-zero"); if ((u64_popcount(page_size) > 1) || (page_size > 16384)) - { #endif + { /* Too big or strange page, use the aligned allocator instead */ page_size = 4096; use_fake = 1; @@ -46,6 +57,22 @@ alloc_sys_page(void) #ifdef HAVE_MMAP if (!use_fake) { + if (atomic_load_explicit(&global_page_list_not_empty, memory_order_relaxed)) + { + GLOBAL_PAGE_SPIN_LOCK; + if (!EMPTY_LIST(global_page_list)) + { + node *ret = HEAD(global_page_list); + rem_node(ret); + if (EMPTY_LIST(global_page_list)) + atomic_store_explicit(&global_page_list_not_empty, 0, memory_order_relaxed); + GLOBAL_PAGE_SPIN_UNLOCK; + memset(ret, 0, sizeof(node)); + return (void *) ret; + } + GLOBAL_PAGE_SPIN_UNLOCK; + } + if (alloc_multipage) { void *big = mmap(NULL, page_size * 2, PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); @@ -90,7 +117,19 @@ free_sys_page(void *ptr) if (!use_fake) { if (munmap(ptr, page_size) < 0) - bug("munmap(%p) failed: %m", ptr); +#ifdef ENOMEM + if (errno == ENOMEM) + { + memset(ptr, 0, page_size); + + GLOBAL_PAGE_SPIN_LOCK; + add_tail(&global_page_list, (node *) ptr); + atomic_store_explicit(&global_page_list_not_empty, 1, memory_order_relaxed); + GLOBAL_PAGE_SPIN_UNLOCK; + } + else +#endif + bug("munmap(%p) failed: %m", ptr); } else #endif |