diff options
Diffstat (limited to 'mm/zsmalloc.c')
| -rw-r--r-- | mm/zsmalloc.c | 74 |
1 files changed, 26 insertions, 48 deletions
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 702bc3fd687a..3aed46ab7e6c 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -73,13 +73,6 @@ */ #define ZS_ALIGN 8 -/* - * A single 'zspage' is composed of up to 2^N discontiguous 0-order (single) - * pages. ZS_MAX_ZSPAGE_ORDER defines upper limit on N. - */ -#define ZS_MAX_ZSPAGE_ORDER 2 -#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(1, UL) << ZS_MAX_ZSPAGE_ORDER) - #define ZS_HANDLE_SIZE (sizeof(unsigned long)) /* @@ -136,10 +129,13 @@ #define HUGE_BITS 1 #define FULLNESS_BITS 2 #define CLASS_BITS 8 -#define ISOLATED_BITS 3 +#define ISOLATED_BITS 5 #define MAGIC_VAL_BITS 8 #define MAX(a, b) ((a) >= (b) ? (a) : (b)) + +#define ZS_MAX_PAGES_PER_ZSPAGE (_AC(CONFIG_ZSMALLOC_CHAIN_SIZE, UL)) + /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ #define ZS_MIN_ALLOC_SIZE \ MAX(32, (ZS_MAX_PAGES_PER_ZSPAGE << PAGE_SHIFT >> OBJ_INDEX_BITS)) @@ -822,42 +818,6 @@ out: return newfg; } -/* - * We have to decide on how many pages to link together - * to form a zspage for each size class. This is important - * to reduce wastage due to unusable space left at end of - * each zspage which is given as: - * wastage = Zp % class_size - * usage = Zp - wastage - * where Zp = zspage size = k * PAGE_SIZE where k = 1, 2, ... - * - * For example, for size class of 3/8 * PAGE_SIZE, we should - * link together 3 PAGE_SIZE sized pages to form a zspage - * since then we can perfectly fit in 8 such objects. - */ -static int get_pages_per_zspage(int class_size) -{ - int i, max_usedpc = 0; - /* zspage order which gives maximum used size per KB */ - int max_usedpc_order = 1; - - for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { - int zspage_size; - int waste, usedpc; - - zspage_size = i * PAGE_SIZE; - waste = zspage_size % class_size; - usedpc = (zspage_size - waste) * 100 / zspage_size; - - if (usedpc > max_usedpc) { - max_usedpc = usedpc; - max_usedpc_order = i; - } - } - - return max_usedpc_order; -} - static struct zspage *get_zspage(struct page *page) { struct zspage *zspage = (struct zspage *)page_private(page); @@ -2056,7 +2016,6 @@ static bool zs_page_isolate(struct page *page, isolate_mode_t mode) * Page is locked so zspage couldn't be destroyed. For detail, look at * lock_zspage in free_zspage. */ - VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(PageIsolated(page), page); zspage = get_zspage(page); @@ -2088,7 +2047,6 @@ static int zs_page_migrate(struct page *newpage, struct page *page, if (mode == MIGRATE_SYNC_NO_COPY) return -EINVAL; - VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); /* The page is locked, so this pointer must remain valid */ @@ -2153,7 +2111,6 @@ static void zs_page_putback(struct page *page) { struct zspage *zspage; - VM_BUG_ON_PAGE(!PageMovable(page), page); VM_BUG_ON_PAGE(!PageIsolated(page), page); zspage = get_zspage(page); @@ -2404,6 +2361,27 @@ static int zs_register_shrinker(struct zs_pool *pool) pool->name); } +static int calculate_zspage_chain_size(int class_size) +{ + int i, min_waste = INT_MAX; + int chain_size = 1; + + if (is_power_of_2(class_size)) + return chain_size; + + for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) { + int waste; + + waste = (i * PAGE_SIZE) % class_size; + if (waste < min_waste) { + min_waste = waste; + chain_size = i; + } + } + + return chain_size; +} + /** * zs_create_pool - Creates an allocation pool to work from. * @name: pool name to be created @@ -2448,7 +2426,7 @@ struct zs_pool *zs_create_pool(const char *name) size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA; if (size > ZS_MAX_ALLOC_SIZE) size = ZS_MAX_ALLOC_SIZE; - pages_per_zspage = get_pages_per_zspage(size); + pages_per_zspage = calculate_zspage_chain_size(size); objs_per_zspage = pages_per_zspage * PAGE_SIZE / size; /* |