1 files changed, 134 insertions, 46 deletions

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 839a48c3ca27..4d0a063145ec 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -155,8 +155,6 @@
  *  (reason above)
  */
 #define ZS_SIZE_CLASS_DELTA     (PAGE_SIZE >> 8)
-#define ZS_SIZE_CLASSES         ((ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE) / \
-                                        ZS_SIZE_CLASS_DELTA + 1)
 
 /*
  * We do not maintain any list for completely empty or full pages
@@ -171,6 +169,11 @@ enum fullness_group {
 };
 
 /*
+ * number of size_classes
+ */
+static int zs_size_classes;
+
+/*
  * We assign a page to ZS_ALMOST_EMPTY fullness group when:
  *      n <= N / f, where
  * n = number of allocated objects
@@ -214,7 +217,7 @@ struct link_free {
 };
 
 struct zs_pool {
-        struct size_class size_class[ZS_SIZE_CLASSES];
+        struct size_class **size_class;
 
         gfp_t flags;    /* allocation flags used when growing pool */
         atomic_long_t pages_allocated;
@@ -468,7 +471,7 @@ static enum fullness_group fix_fullness_group(struct zs_pool *pool,
         if (newfg == currfg)
                 goto out;
 
-        class = &pool->size_class[class_idx];
+        class = pool->size_class[class_idx];
         remove_zspage(page, class, currfg);
         insert_zspage(page, class, newfg);
         set_zspage_mapping(page, class_idx, newfg);
@@ -629,6 +632,7 @@ static void init_zspage(struct page *first_page, struct size_class *class)
                 struct page *next_page;
                 struct link_free *link;
                 unsigned int i = 1;
+                void *vaddr;
 
                 /*
                  * page->index stores offset of first object starting
@@ -639,8 +643,8 @@ static void init_zspage(struct page *first_page, struct size_class *class)
                 if (page != first_page)
                         page->index = off;
 
-                link = (struct link_free *)kmap_atomic(page) +
-                                                off / sizeof(*link);
+                vaddr = kmap_atomic(page);
+                link = (struct link_free *)vaddr + off / sizeof(*link);
 
                 while ((off += class->size) < PAGE_SIZE) {
                         link->next = obj_location_to_handle(page, i++);
@@ -654,7 +658,7 @@ static void init_zspage(struct page *first_page, struct size_class *class)
                  */
                 next_page = get_next_page(page);
                 link->next = obj_location_to_handle(next_page, 0);
-                kunmap_atomic(link);
+                kunmap_atomic(vaddr);
                 page = next_page;
                 off %= PAGE_SIZE;
         }
@@ -784,7 +788,7 @@ static inline int __zs_cpu_up(struct mapping_area *area)
          */
         if (area->vm_buf)
                 return 0;
-        area->vm_buf = (char *)__get_free_page(GFP_KERNEL);
+        area->vm_buf = kmalloc(ZS_MAX_ALLOC_SIZE, GFP_KERNEL);
         if (!area->vm_buf)
                 return -ENOMEM;
         return 0;
@@ -792,8 +796,7 @@ static inline int __zs_cpu_up(struct mapping_area *area)
 
 static inline void __zs_cpu_down(struct mapping_area *area)
 {
-        if (area->vm_buf)
-                free_page((unsigned long)area->vm_buf);
+        kfree(area->vm_buf);
         area->vm_buf = NULL;
 }
 
@@ -881,14 +884,10 @@ static struct notifier_block zs_cpu_nb = {
         .notifier_call = zs_cpu_notifier
 };
 
-static void zs_exit(void)
+static void zs_unregister_cpu_notifier(void)
 {
         int cpu;
 
-#ifdef CONFIG_ZPOOL
-        zpool_unregister_driver(&zs_zpool_driver);
-#endif
-
         cpu_notifier_register_begin();
 
         for_each_online_cpu(cpu)
@@ -898,31 +897,74 @@ static void zs_exit(void)
         cpu_notifier_register_done();
 }
 
-static int zs_init(void)
+static int zs_register_cpu_notifier(void)
 {
-        int cpu, ret;
+        int cpu, uninitialized_var(ret);
 
         cpu_notifier_register_begin();
 
         __register_cpu_notifier(&zs_cpu_nb);
         for_each_online_cpu(cpu) {
                 ret = zs_cpu_notifier(NULL, CPU_UP_PREPARE, (void *)(long)cpu);
-                if (notifier_to_errno(ret)) {
-                        cpu_notifier_register_done();
-                        goto fail;
-                }
+                if (notifier_to_errno(ret))
+                        break;
         }
 
         cpu_notifier_register_done();
+        return notifier_to_errno(ret);
+}
+
+static void 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 void __exit zs_exit(void)
+{
 #ifdef CONFIG_ZPOOL
-        zpool_register_driver(&zs_zpool_driver);
+        zpool_unregister_driver(&zs_zpool_driver);
 #endif
+        zs_unregister_cpu_notifier();
+}
 
+static int __init zs_init(void)
+{
+        int ret = zs_register_cpu_notifier();
+
+        if (ret) {
+                zs_unregister_cpu_notifier();
+                return ret;
+        }
+
+        init_zs_size_classes();
+
+#ifdef CONFIG_ZPOOL
+        zpool_register_driver(&zs_zpool_driver);
+#endif
         return 0;
-fail:
-        zs_exit();
-        return notifier_to_errno(ret);
+}
+
+static unsigned int get_maxobj_per_zspage(int size, int pages_per_zspage)
+{
+        return pages_per_zspage * PAGE_SIZE / size;
+}
+
+static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
+{
+        if (prev->pages_per_zspage != pages_per_zspage)
+                return false;
+
+        if (get_maxobj_per_zspage(prev->size, prev->pages_per_zspage)
+                != get_maxobj_per_zspage(size, pages_per_zspage))
+                return false;
+
+        return true;
 }
 
 /**
@@ -937,33 +979,71 @@ fail:
  */
 struct zs_pool *zs_create_pool(gfp_t flags)
 {
-        int i, ovhd_size;
+        int i;
         struct zs_pool *pool;
+        struct size_class *prev_class = NULL;
 
-        ovhd_size = roundup(sizeof(*pool), PAGE_SIZE);
-        pool = kzalloc(ovhd_size, GFP_KERNEL);
+        pool = kzalloc(sizeof(*pool), GFP_KERNEL);
         if (!pool)
                 return NULL;
 
-        for (i = 0; i < ZS_SIZE_CLASSES; i++) {
+        pool->size_class = kcalloc(zs_size_classes, sizeof(struct size_class *),
+                        GFP_KERNEL);
+        if (!pool->size_class) {
+                kfree(pool);
+                return NULL;
+        }
+
+        /*
+         * Iterate reversly, 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--) {
                 int size;
+                int pages_per_zspage;
                 struct size_class *class;
 
                 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);
+
+                /*
+                 * size_class is used for normal zsmalloc operation such
+                 * as alloc/free for that size. Although it is natural that we
+                 * have one size_class for each size, there is a chance that we
+                 * can get more memory utilization if we use one size_class for
+                 * many different sizes whose size_class have same
+                 * characteristics. So, we makes size_class point to
+                 * previous size_class if possible.
+                 */
+                if (prev_class) {
+                        if (can_merge(prev_class, size, pages_per_zspage)) {
+                                pool->size_class[i] = prev_class;
+                                continue;
+                        }
+                }
+
+                class = kzalloc(sizeof(struct size_class), GFP_KERNEL);
+                if (!class)
+                        goto err;
 
-                class = &pool->size_class[i];
                 class->size = size;
                 class->index = i;
+                class->pages_per_zspage = pages_per_zspage;
                 spin_lock_init(&class->lock);
-                class->pages_per_zspage = get_pages_per_zspage(size);
+                pool->size_class[i] = class;
 
+                prev_class = class;
         }
 
         pool->flags = flags;
 
         return pool;
+
+err:
+        zs_destroy_pool(pool);
+        return NULL;
 }
 EXPORT_SYMBOL_GPL(zs_create_pool);
 
@@ -971,9 +1051,15 @@ void zs_destroy_pool(struct zs_pool *pool)
 {
         int i;
 
-        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];
+                struct size_class *class = pool->size_class[i];
+
+                if (!class)
+                        continue;
+
+                if (class->index != i)
+                        continue;
 
                 for (fg = 0; fg < _ZS_NR_FULLNESS_GROUPS; fg++) {
                         if (class->fullness_list[fg]) {
@@ -981,7 +1067,10 @@ void zs_destroy_pool(struct zs_pool *pool)
                                         class->size, fg);
                         }
                 }
+                kfree(class);
         }
+
+        kfree(pool->size_class);
         kfree(pool);
 }
 EXPORT_SYMBOL_GPL(zs_destroy_pool);
@@ -999,8 +1088,8 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
 {
         unsigned long obj;
         struct link_free *link;
-        int class_idx;
         struct size_class *class;
+        void *vaddr;
 
         struct page *first_page, *m_page;
         unsigned long m_objidx, m_offset;
@@ -1008,9 +1097,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
         if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
                 return 0;
 
-        class_idx = get_size_class_index(size);
-        class = &pool->size_class[class_idx];
-        BUG_ON(class_idx != class->index);
+        class = pool->size_class[get_size_class_index(size)];
 
         spin_lock(&class->lock);
         first_page = find_get_zspage(class);
@@ -1031,11 +1118,11 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size)
         obj_handle_to_location(obj, &m_page, &m_objidx);
         m_offset = obj_idx_to_offset(m_page, m_objidx, class->size);
 
-        link = (struct link_free *)kmap_atomic(m_page) +
-                                        m_offset / sizeof(*link);
+        vaddr = kmap_atomic(m_page);
+        link = (struct link_free *)vaddr + m_offset / sizeof(*link);
         first_page->freelist = link->next;
         memset(link, POISON_INUSE, sizeof(*link));
-        kunmap_atomic(link);
+        kunmap_atomic(vaddr);
 
         first_page->inuse++;
         /* Now move the zspage to another fullness group, if required */
@@ -1051,6 +1138,7 @@ void zs_free(struct zs_pool *pool, unsigned long obj)
         struct link_free *link;
         struct page *first_page, *f_page;
         unsigned long f_objidx, f_offset;
+        void *vaddr;
 
         int class_idx;
         struct size_class *class;
@@ -1063,16 +1151,16 @@ void zs_free(struct zs_pool *pool, unsigned long obj)
         first_page = get_first_page(f_page);
 
         get_zspage_mapping(first_page, &class_idx, &fullness);
-        class = &pool->size_class[class_idx];
+        class = pool->size_class[class_idx];
         f_offset = obj_idx_to_offset(f_page, f_objidx, class->size);
 
         spin_lock(&class->lock);
 
         /* Insert this object in containing zspage's freelist */
-        link = (struct link_free *)((unsigned char *)kmap_atomic(f_page)
-                                                        + f_offset);
+        vaddr = kmap_atomic(f_page);
+        link = (struct link_free *)(vaddr + f_offset);
         link->next = first_page->freelist;
-        kunmap_atomic(link);
+        kunmap_atomic(vaddr);
         first_page->freelist = (void *)obj;
 
         first_page->inuse--;
@@ -1124,7 +1212,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 
         obj_handle_to_location(handle, &page, &obj_idx);
         get_zspage_mapping(get_first_page(page), &class_idx, &fg);
-        class = &pool->size_class[class_idx];
+        class = pool->size_class[class_idx];
         off = obj_idx_to_offset(page, obj_idx, class->size);
 
         area = &get_cpu_var(zs_map_area);
@@ -1158,7 +1246,7 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 
         obj_handle_to_location(handle, &page, &obj_idx);
         get_zspage_mapping(get_first_page(page), &class_idx, &fg);
-        class = &pool->size_class[class_idx];
+        class = pool->size_class[class_idx];
         off = obj_idx_to_offset(page, obj_idx, class->size);
 
         area = this_cpu_ptr(&zs_map_area);