From c78247f9b97802d6fe76d9b7cddf2c1940134d33 Mon Sep 17 00:00:00 2001 From: Maria Matejka Date: Wed, 9 Mar 2022 09:10:44 +0100 Subject: [PATCH] Single-threaded version of sark-branch memory page management --- lib/resource.c | 2 + lib/resource.h | 5 +- lib/slab.c | 13 ++- nest/cmds.c | 5 +- sysdep/unix/alloc.c | 199 ++++++++++++++++++++++++++++---------------- 5 files changed, 141 insertions(+), 83 deletions(-) diff --git a/lib/resource.c b/lib/resource.c index 5636872c..a179afe3 100644 --- a/lib/resource.c +++ b/lib/resource.c @@ -270,6 +270,8 @@ rlookup(unsigned long a) void resource_init(void) { + resource_sys_init(); + root_pool.r.class = &pool_class; root_pool.name = "Root"; init_list(&root_pool.inside); diff --git a/lib/resource.h b/lib/resource.h index 0e4c44d8..992fa5b2 100644 --- a/lib/resource.h +++ b/lib/resource.h @@ -110,10 +110,11 @@ void sl_free(slab *, void *); void buffer_realloc(void **buf, unsigned *size, unsigned need, unsigned item_size); /* Allocator of whole pages; for use in slabs and other high-level allocators. */ -u64 get_page_size(void); +extern long page_size; void *alloc_page(void); void free_page(void *); -extern uint pages_kept; + +void resource_sys_init(void); #ifdef HAVE_LIBDMALLOC /* diff --git a/lib/slab.c b/lib/slab.c index 9a4c3ee2..9be9844d 100644 --- a/lib/slab.c +++ b/lib/slab.c @@ -180,7 +180,7 @@ struct sl_alignment { /* Magic structure for testing of alignment */ int x[0]; }; -#define SL_GET_HEAD(x) ((struct sl_head *) (((uintptr_t) (x)) & ~(get_page_size()-1))) +#define SL_GET_HEAD(x) ((struct sl_head *) (((uintptr_t) (x)) & ~(page_size-1))) /** * sl_new - create a new Slab @@ -202,7 +202,6 @@ sl_new(pool *p, uint size) s->obj_size = size; s->head_size = sizeof(struct sl_head); - u64 page_size = get_page_size(); do { s->objs_per_slab = (page_size - s->head_size) / size; @@ -273,7 +272,7 @@ no_partial: } h = alloc_page(); #ifdef POISON - memset(h, 0xba, get_page_size()); + memset(h, 0xba, page_size); #endif ASSERT_DIE(SL_GET_HEAD(h) == h); memset(h, 0, s->head_size); @@ -332,7 +331,7 @@ sl_free(slab *s, void *oo) if (s->num_empty_heads >= MAX_EMPTY_HEADS) { #ifdef POISON - memset(h, 0xde, get_page_size()); + memset(h, 0xde, page_size); #endif free_page(h); } @@ -399,7 +398,7 @@ slab_memsize(resource *r) return (struct resmem) { .effective = eff, - .overhead = ALLOC_OVERHEAD + sizeof(struct slab) + heads * get_page_size() - eff, + .overhead = ALLOC_OVERHEAD + sizeof(struct slab) + heads * page_size - eff, }; } @@ -410,10 +409,10 @@ slab_lookup(resource *r, unsigned long a) struct sl_head *h; WALK_LIST(h, s->partial_heads) - if ((unsigned long) h < a && (unsigned long) h + get_page_size() < a) + if ((unsigned long) h < a && (unsigned long) h + page_size < a) return r; WALK_LIST(h, s->full_heads) - if ((unsigned long) h < a && (unsigned long) h + get_page_size() < a) + if ((unsigned long) h < a && (unsigned long) h + page_size < a) return r; return NULL; } diff --git a/nest/cmds.c b/nest/cmds.c index 1a16f9c7..8481bf96 100644 --- a/nest/cmds.c +++ b/nest/cmds.c @@ -108,6 +108,7 @@ print_size(char *dsc, struct resmem vals) extern pool *rt_table_pool; extern pool *rta_pool; +extern uint *pages_kept; void cmd_show_memory(void) @@ -119,8 +120,8 @@ cmd_show_memory(void) print_size("Protocols:", rmemsize(proto_pool)); struct resmem total = rmemsize(&root_pool); #ifdef HAVE_MMAP - print_size("Standby memory:", (struct resmem) { .overhead = get_page_size() * pages_kept }); - total.overhead += get_page_size() * pages_kept; + print_size("Standby memory:", (struct resmem) { .overhead = page_size * *pages_kept }); + total.overhead += page_size * *pages_kept; #endif print_size("Total:", total); cli_msg(0, ""); diff --git a/sysdep/unix/alloc.c b/sysdep/unix/alloc.c index 0e944d57..f96c0fcf 100644 --- a/sysdep/unix/alloc.c +++ b/sysdep/unix/alloc.c @@ -11,6 +11,7 @@ #include "lib/lists.h" #include "lib/event.h" +#include #include #include @@ -18,113 +19,167 @@ #include #endif -#ifdef HAVE_MMAP -#define KEEP_PAGES 512 +long page_size = 0; + +#ifdef HAVE_MMAP +#define KEEP_PAGES_MAIN_MAX 256 +#define KEEP_PAGES_MAIN_MIN 8 +#define CLEANUP_PAGES_BULK 256 + +_Static_assert(KEEP_PAGES_MAIN_MIN * 4 < KEEP_PAGES_MAIN_MAX); -static u64 page_size = 0; static _Bool use_fake = 0; -uint pages_kept = 0; -static list pages_list; - -static void cleanup_pages(void *data); -static event page_cleanup_event = { .hook = cleanup_pages }; - +#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); - - memset(ptr, 0, sizeof(node)); - add_tail(&pages_list, ptr); - - if (++pages_kept > KEEP_PAGES) - ev_schedule(&page_cleanup_event); - } - else -#endif free(ptr); + return; + } + +#ifdef HAVE_MMAP + struct free_pages *fps = &global_free_pages; + struct free_page *fp = ptr; + + fp->n = (node) {}; + add_tail(&fps->pages, &fp->n); + + if ((++fps->cnt > fps->max) && !shutting_down) + ev_schedule(&fps->cleanup); +#endif } #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 - else if (errno == ENOMEM) - add_tail(&pages_list, ptr); -#endif - else - bug("munmap(%p) failed: %m", ptr); + struct free_page *fp = alloc_sys_page(); + fp->n = (node) {}; + add_tail(&fps->pages, &fp->n); + fps->cnt++; } - if (pages_kept > KEEP_PAGES) - ev_schedule(&page_cleanup_event); + 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_head(&fps->pages, &fp->n); + else + bug("munmap(%p) failed: %m", fp); + } } #endif + +void +resource_sys_init(void) +{ +#ifdef HAVE_MMAP + 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; +}