diff options
Diffstat (limited to 'sysdep/unix/alloc.c')
| -rw-r--r-- | sysdep/unix/alloc.c | 193 |
1 files changed, 125 insertions, 68 deletions
diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c index 0e944d57..755b5fa5 100644 --- a/sysdep/unix/alloc.c +++ b/sysdep/unix/alloc.c @@ -11,6 +11,7 @@ #include "lib/lists.h" #include "lib/event.h" +#include <errno.h> #include <stdlib.h> #include <unistd.h> @@ -18,113 +19,169 @@ #include <sys/mman.h> #endif -#ifdef HAVE_MMAP -#define KEEP_PAGES 512 +long page_size = 0; -static u64 page_size = 0; -static _Bool use_fake = 0; +#ifdef HAVE_MMAP +#define KEEP_PAGES_MAIN_MAX 256 +#define KEEP_PAGES_MAIN_MIN 8 +#define CLEANUP_PAGES_BULK 256 -uint pages_kept = 0; -static list pages_list; +_Static_assert(KEEP_PAGES_MAIN_MIN * 4 < KEEP_PAGES_MAIN_MAX); -static void cleanup_pages(void *data); -static event page_cleanup_event = { .hook = cleanup_pages }; +static _Bool use_fake = 0; +#if DEBUGGING +struct free_page { + node unused[42]; + node n; +}; #else -static const u64 page_size = 4096; /* Fake page size */ +struct free_page { + node n; +}; #endif -u64 get_page_size(void) +struct free_pages { + list pages; + u16 min, max; /* Minimal and maximal number of free pages kept */ + uint cnt; /* Number of empty pages */ + event cleanup; +}; + +static void global_free_pages_cleanup_event(void *); + +static struct free_pages global_free_pages = { + .min = KEEP_PAGES_MAIN_MIN, + .max = KEEP_PAGES_MAIN_MAX, + .cleanup = { .hook = global_free_pages_cleanup_event }, +}; + +uint *pages_kept = &global_free_pages.cnt; + +static void * +alloc_sys_page(void) { - if (page_size) - return page_size; + void *ptr = mmap(NULL, page_size, PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); -#ifdef HAVE_MMAP - if (page_size = sysconf(_SC_PAGESIZE)) - { - if ((u64_popcount(page_size) > 1) || (page_size > 16384)) - { - /* Too big or strange page, use the aligned allocator instead */ - page_size = 4096; - use_fake = 1; - } - return page_size; - } + if (ptr == MAP_FAILED) + bug("mmap(%lu) failed: %m", page_size); - bug("Page size must be non-zero"); -#endif + return ptr; } +extern int shutting_down; /* Shutdown requested. */ + +#else // ! HAVE_MMAP +#define use_fake 1 +#endif + void * alloc_page(void) { -#ifdef HAVE_MMAP - if (pages_kept) - { - node *page = TAIL(pages_list); - rem_node(page); - pages_kept--; - memset(page, 0, get_page_size()); - return page; - } - - if (!use_fake) - { - void *ret = mmap(NULL, get_page_size(), PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); - if (ret == MAP_FAILED) - bug("mmap(%lu) failed: %m", (long unsigned int) page_size); - return ret; - } - else -#endif + if (use_fake) { void *ptr = NULL; int err = posix_memalign(&ptr, page_size, page_size); + if (err || !ptr) bug("posix_memalign(%lu) failed", (long unsigned int) page_size); + return ptr; } + +#ifdef HAVE_MMAP + struct free_pages *fps = &global_free_pages; + + if (fps->cnt) + { + struct free_page *fp = SKIP_BACK(struct free_page, n, HEAD(fps->pages)); + rem_node(&fp->n); + if ((--fps->cnt < fps->min) && !shutting_down) + ev_schedule(&fps->cleanup); + + bzero(fp, page_size); + return fp; + } + + return alloc_sys_page(); +#endif } void free_page(void *ptr) { -#ifdef HAVE_MMAP - if (!use_fake) + if (use_fake) { - if (!pages_kept) - init_list(&pages_list); + free(ptr); + return; + } + +#ifdef HAVE_MMAP + struct free_pages *fps = &global_free_pages; + struct free_page *fp = ptr; - memset(ptr, 0, sizeof(node)); - add_tail(&pages_list, ptr); + fp->n = (node) {}; + add_tail(&fps->pages, &fp->n); - if (++pages_kept > KEEP_PAGES) - ev_schedule(&page_cleanup_event); - } - else + if ((++fps->cnt > fps->max) && !shutting_down) + ev_schedule(&fps->cleanup); #endif - free(ptr); } #ifdef HAVE_MMAP static void -cleanup_pages(void *data UNUSED) +global_free_pages_cleanup_event(void *data UNUSED) { - for (uint seen = 0; (pages_kept > KEEP_PAGES) && (seen < KEEP_PAGES); seen++) + if (shutting_down) + return; + + struct free_pages *fps = &global_free_pages; + + while (fps->cnt / 2 < fps->min) { - void *ptr = HEAD(pages_list); - rem_node(ptr); - if (munmap(ptr, get_page_size()) == 0) - pages_kept--; -#ifdef ENOMEM + struct free_page *fp = alloc_sys_page(); + fp->n = (node) {}; + add_tail(&fps->pages, &fp->n); + fps->cnt++; + } + + for (uint seen = 0; (seen < CLEANUP_PAGES_BULK) && (fps->cnt > fps->max / 2); seen++) + { + struct free_page *fp = SKIP_BACK(struct free_page, n, TAIL(fps->pages)); + rem_node(&fp->n); + + if (munmap(fp, page_size) == 0) + fps->cnt--; else if (errno == ENOMEM) - add_tail(&pages_list, ptr); -#endif + add_head(&fps->pages, &fp->n); else - bug("munmap(%p) failed: %m", ptr); + bug("munmap(%p) failed: %m", fp); } - - if (pages_kept > KEEP_PAGES) - ev_schedule(&page_cleanup_event); } #endif + +void +resource_sys_init(void) +{ +#ifdef HAVE_MMAP + ASSERT_DIE(global_free_pages.cnt == 0); + + if (!(page_size = sysconf(_SC_PAGESIZE))) + die("System page size must be non-zero"); + + if (u64_popcount(page_size) == 1) + { + struct free_pages *fps = &global_free_pages; + + init_list(&fps->pages); + global_free_pages_cleanup_event(NULL); + return; + } + + /* Too big or strange page, use the aligned allocator instead */ + log(L_WARN "Got strange memory page size (%lu), using the aligned allocator instead", page_size); + use_fake = 1; +#endif + + page_size = 4096; +} |