From cf8e0fedf0784ef4bc1889380b09eda295e3d109 Mon Sep 17 00:00:00 2001 From: Jerome Marchand Date: Mon, 10 Jul 2017 15:50:18 -0700 Subject: [PATCH] mm/zsmalloc: simplify zs_max_alloc_size handling Commit 40f9fb8cffc6 ("mm/zsmalloc: support allocating obj with size of ZS_MAX_ALLOC_SIZE") fixes a size calculation error that prevented zsmalloc to allocate an object of the maximal size (ZS_MAX_ALLOC_SIZE). I think however the fix is unneededly complicated. This patch replaces the dynamic calculation of zs_size_classes at init time by a compile time calculation that uses the DIV_ROUND_UP() macro already used in get_size_class_index(). [akpm@linux-foundation.org: use min_t] Link: http://lkml.kernel.org/r/20170630114859.1979-1-jmarchan@redhat.com Signed-off-by: Jerome Marchand Acked-by: Minchan Kim Cc: Sergey Senozhatsky Cc: Mahendran Ganesh Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zsmalloc.c | 52 +++++++++++++++------------------------------------ 1 file changed, 15 insertions(+), 37 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 15959d35fc26..013eea76685e 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -116,6 +116,11 @@ #define OBJ_INDEX_BITS (BITS_PER_LONG - _PFN_BITS - OBJ_TAG_BITS) #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1) +#define FULLNESS_BITS 2 +#define CLASS_BITS 8 +#define ISOLATED_BITS 3 +#define MAGIC_VAL_BITS 8 + #define MAX(a, b) ((a) >= (b) ? (a) : (b)) /* ZS_MIN_ALLOC_SIZE must be multiple of ZS_ALIGN */ #define ZS_MIN_ALLOC_SIZE \ @@ -137,6 +142,8 @@ * (reason above) */ #define ZS_SIZE_CLASS_DELTA (PAGE_SIZE >> CLASS_BITS) +#define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \ + ZS_SIZE_CLASS_DELTA) + 1) enum fullness_group { ZS_EMPTY, @@ -168,11 +175,6 @@ static struct dentry *zs_stat_root; static struct vfsmount *zsmalloc_mnt; #endif -/* - * number of size_classes - */ -static int zs_size_classes; - /* * We assign a page to ZS_ALMOST_EMPTY fullness group when: * n <= N / f, where @@ -244,7 +246,7 @@ struct link_free { struct zs_pool { const char *name; - struct size_class **size_class; + struct size_class *size_class[ZS_SIZE_CLASSES]; struct kmem_cache *handle_cachep; struct kmem_cache *zspage_cachep; @@ -268,11 +270,6 @@ struct zs_pool { #endif }; -#define FULLNESS_BITS 2 -#define CLASS_BITS 8 -#define ISOLATED_BITS 3 -#define MAGIC_VAL_BITS 8 - struct zspage { struct { unsigned int fullness:FULLNESS_BITS; @@ -551,7 +548,7 @@ static int get_size_class_index(int size) idx = DIV_ROUND_UP(size - ZS_MIN_ALLOC_SIZE, ZS_SIZE_CLASS_DELTA); - return min(zs_size_classes - 1, idx); + return min_t(int, ZS_SIZE_CLASSES - 1, idx); } static inline void zs_stat_inc(struct size_class *class, @@ -610,7 +607,7 @@ static int zs_stats_size_show(struct seq_file *s, void *v) "obj_allocated", "obj_used", "pages_used", "pages_per_zspage", "freeable"); - for (i = 0; i < zs_size_classes; i++) { + for (i = 0; i < ZS_SIZE_CLASSES; i++) { class = pool->size_class[i]; if (class->index != i) @@ -1294,17 +1291,6 @@ static int zs_cpu_dead(unsigned int cpu) return 0; } -static void __init init_zs_size_classes(void) -{ - int nr; - - nr = (ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / ZS_SIZE_CLASS_DELTA + 1; - if ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) % ZS_SIZE_CLASS_DELTA) - nr += 1; - - zs_size_classes = nr; -} - static bool can_merge(struct size_class *prev, int pages_per_zspage, int objs_per_zspage) { @@ -2145,7 +2131,7 @@ static void async_free_zspage(struct work_struct *work) struct zs_pool *pool = container_of(work, struct zs_pool, free_work); - for (i = 0; i < zs_size_classes; i++) { + for (i = 0; i < ZS_SIZE_CLASSES; i++) { class = pool->size_class[i]; if (class->index != i) continue; @@ -2263,7 +2249,7 @@ unsigned long zs_compact(struct zs_pool *pool) int i; struct size_class *class; - for (i = zs_size_classes - 1; i >= 0; i--) { + for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { class = pool->size_class[i]; if (!class) continue; @@ -2309,7 +2295,7 @@ static unsigned long zs_shrinker_count(struct shrinker *shrinker, struct zs_pool *pool = container_of(shrinker, struct zs_pool, shrinker); - for (i = zs_size_classes - 1; i >= 0; i--) { + for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { class = pool->size_class[i]; if (!class) continue; @@ -2361,12 +2347,6 @@ struct zs_pool *zs_create_pool(const char *name) return NULL; init_deferred_free(pool); - pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *), - GFP_KERNEL); - if (!pool->size_class) { - kfree(pool); - return NULL; - } pool->name = kstrdup(name, GFP_KERNEL); if (!pool->name) @@ -2379,7 +2359,7 @@ struct zs_pool *zs_create_pool(const char *name) * Iterate reversely, because, size of size_class that we want to use * for merging should be larger or equal to current size. */ - for (i = zs_size_classes - 1; i >= 0; i--) { + for (i = ZS_SIZE_CLASSES - 1; i >= 0; i--) { int size; int pages_per_zspage; int objs_per_zspage; @@ -2453,7 +2433,7 @@ void zs_destroy_pool(struct zs_pool *pool) zs_unregister_migration(pool); zs_pool_stat_destroy(pool); - for (i = 0; i < zs_size_classes; i++) { + for (i = 0; i < ZS_SIZE_CLASSES; i++) { int fg; struct size_class *class = pool->size_class[i]; @@ -2492,8 +2472,6 @@ static int __init zs_init(void) if (ret) goto hp_setup_fail; - init_zs_size_classes(); - #ifdef CONFIG_ZPOOL zpool_register_driver(&zs_zpool_driver); #endif