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Date: Fri, 3 Mar 2023 08:55:36 -0800
From: Yosry Ahmed <yosryahmed@...gle.com>
To: Sergey Senozhatsky <senozhatsky@...omium.org>
Cc: Minchan Kim <minchan@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCHv3 2/4] zsmalloc: fine-grained inuse ratio based fullness grouping
Hi Sergey,
Thanks for working on this!
On Thu, Mar 2, 2023 at 11:31 PM Sergey Senozhatsky
<senozhatsky@...omium.org> wrote:
>
> Each zspage maintains ->inuse counter which keeps track of the
> number of objects stored in the zspage. The ->inuse counter also
> determines the zspage's "fullness group" which is calculated as
> the ratio of the "inuse" objects to the total number of objects
> the zspage can hold (objs_per_zspage). The closer the ->inuse
> counter is to objs_per_zspage, the better.
>
> Each size class maintains several fullness lists, that keep
> track of zspages of particular "fullness". Pages within each
> fullness list are stored in random order with regard to the
> ->inuse counter. This is because sorting the zspages by ->inuse
> counter each time obj_malloc() or obj_free() is called would
> be too expensive. However, the ->inuse counter is still a
> crucial factor in many situations.
>
> For the two major zsmalloc operations, zs_malloc() and zs_compact(),
> we typically select the head zspage from the corresponding fullness
> list as the best candidate zspage. However, this assumption is not
> always accurate.
>
> For the zs_malloc() operation, the optimal candidate zspage should
> have the highest ->inuse counter. This is because the goal is to
> maximize the number of ZS_FULL zspages and make full use of all
> allocated memory.
>
> For the zs_compact() operation, the optimal source zspage should
> have the lowest ->inuse counter. This is because compaction needs
> to move objects in use to another page before it can release the
> zspage and return its physical pages to the buddy allocator. The
> fewer objects in use, the quicker compaction can release the zspage.
> Additionally, compaction is measured by the number of pages it
> releases.
>
> This patch reworks the fullness grouping mechanism. Instead of
> having two groups - ZS_ALMOST_EMPTY (usage ratio below 3/4) and
> ZS_ALMOST_FULL (usage ration above 3/4) - that result in too many
> zspages being included in the ALMOST_EMPTY group for specific
> classes, size classes maintain a larger number of fullness lists
> that give strict guarantees on the minimum and maximum ->inuse
> values within each group. Each group represents a 10% change in the
> ->inuse ratio compared to neighboring groups. In essence, there
> are groups for zspages with 0%, 10%, 20% usage ratios, and so on,
> up to 100%.
>
> This enhances the selection of candidate zspages for both zs_malloc()
> and zs_compact(). A printout of the ->inuse counters of the first 7
> zspages per (random) class fullness group:
>
> class-768 objs_per_zspage 16:
> fullness 100%: empty
> fullness 99%: empty
> fullness 90%: empty
> fullness 80%: empty
> fullness 70%: empty
> fullness 60%: 8 8 9 9 8 8 8
> fullness 50%: empty
> fullness 40%: 5 5 6 5 5 5 5
> fullness 30%: 4 4 4 4 4 4 4
> fullness 20%: 2 3 2 3 3 2 2
> fullness 10%: 1 1 1 1 1 1 1
> fullness 0%: empty
>
> The zs_malloc() function searches through the groups of pages
> starting with the one having the highest usage ratio. This means
> that it always selects a zspage from the group with the least
> internal fragmentation (highest usage ratio) and makes it even
> less fragmented by increasing its usage ratio.
>
> The zs_compact() function, on the other hand, begins by scanning
> the group with the highest fragmentation (lowest usage ratio) to
> locate the source page. The first available zspage is selected, and
> then the function moves downward to find a destination zspage in
> the group with the lowest internal fragmentation (highest usage
> ratio).
>
> Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
> ---
> mm/zsmalloc.c | 245 ++++++++++++++++++++++++++------------------------
> 1 file changed, 128 insertions(+), 117 deletions(-)
>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 1cd180caff76..630854575c30 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -127,7 +127,7 @@
> #define OBJ_INDEX_MASK ((_AC(1, UL) << OBJ_INDEX_BITS) - 1)
>
> #define HUGE_BITS 1
> -#define FULLNESS_BITS 2
> +#define FULLNESS_BITS 4
> #define CLASS_BITS 8
> #define ISOLATED_BITS 5
> #define MAGIC_VAL_BITS 8
> @@ -159,51 +159,46 @@
> #define ZS_SIZE_CLASSES (DIV_ROUND_UP(ZS_MAX_ALLOC_SIZE - ZS_MIN_ALLOC_SIZE, \
> ZS_SIZE_CLASS_DELTA) + 1)
>
> +/*
> + * Pages are distinguished by the ratio of used memory (that is the ratio
> + * of ->inuse objects to all objects that page can store). For example,
> + * INUSE_RATIO_10 means that the ratio of used objects is > 0% and <= 10%.
> + *
> + * The number of fullness groups is not random. It allows us to keep
> + * diffeence between the least busy page in the group (minimum permitted
> + * number of ->inuse objects) and the most busy page (maximum permitted
> + * number of ->inuse objects) at a reasonable value.
> + */
> enum fullness_group {
> - ZS_EMPTY,
> - ZS_ALMOST_EMPTY,
> - ZS_ALMOST_FULL,
> - ZS_FULL,
> - NR_ZS_FULLNESS,
> + ZS_INUSE_RATIO_0,
> + ZS_INUSE_RATIO_10,
> + /* NOTE: 5 more fullness groups here */
> + ZS_INUSE_RATIO_70 = 7,
> + /* NOTE: 2 more fullness groups here */
> + ZS_INUSE_RATIO_99 = 10,
> + ZS_INUSE_RATIO_100,
> + NR_FULLNESS_GROUPS,
> };
>
> enum class_stat_type {
> - CLASS_EMPTY,
> - CLASS_ALMOST_EMPTY,
> - CLASS_ALMOST_FULL,
> - CLASS_FULL,
> - OBJ_ALLOCATED,
> - OBJ_USED,
> - NR_ZS_STAT_TYPE,
> + /* NOTE: stats for 12 fullness groups here: from inuse 0 to 100 */
> + ZS_OBJS_ALLOCATED = NR_FULLNESS_GROUPS,
> + ZS_OBJS_INUSE,
> + NR_CLASS_STAT_TYPES,
> };
>
> struct zs_size_stat {
> - unsigned long objs[NR_ZS_STAT_TYPE];
> + unsigned long objs[NR_CLASS_STAT_TYPES];
> };
>
> #ifdef CONFIG_ZSMALLOC_STAT
> static struct dentry *zs_stat_root;
> #endif
>
> -/*
> - * We assign a page to ZS_ALMOST_EMPTY fullness group when:
> - * n <= N / f, where
> - * n = number of allocated objects
> - * N = total number of objects zspage can store
> - * f = fullness_threshold_frac
> - *
> - * Similarly, we assign zspage to:
> - * ZS_ALMOST_FULL when n > N / f
> - * ZS_EMPTY when n == 0
> - * ZS_FULL when n == N
> - *
> - * (see: fix_fullness_group())
> - */
> -static const int fullness_threshold_frac = 4;
> static size_t huge_class_size;
>
> struct size_class {
> - struct list_head fullness_list[NR_ZS_FULLNESS];
> + struct list_head fullness_list[NR_FULLNESS_GROUPS];
> /*
> * Size of objects stored in this class. Must be multiple
> * of ZS_ALIGN.
> @@ -547,8 +542,8 @@ static inline void set_freeobj(struct zspage *zspage, unsigned int obj)
> }
>
> static void get_zspage_mapping(struct zspage *zspage,
> - unsigned int *class_idx,
> - enum fullness_group *fullness)
> + unsigned int *class_idx,
> + int *fullness)
> {
> BUG_ON(zspage->magic != ZSPAGE_MAGIC);
>
> @@ -557,14 +552,14 @@ static void get_zspage_mapping(struct zspage *zspage,
> }
>
> static struct size_class *zspage_class(struct zs_pool *pool,
> - struct zspage *zspage)
> + struct zspage *zspage)
> {
> return pool->size_class[zspage->class];
> }
>
> static void set_zspage_mapping(struct zspage *zspage,
> - unsigned int class_idx,
> - enum fullness_group fullness)
> + unsigned int class_idx,
> + int fullness)
> {
> zspage->class = class_idx;
> zspage->fullness = fullness;
> @@ -588,23 +583,19 @@ static int get_size_class_index(int size)
> return min_t(int, ZS_SIZE_CLASSES - 1, idx);
> }
>
> -/* type can be of enum type class_stat_type or fullness_group */
> static inline void class_stat_inc(struct size_class *class,
> int type, unsigned long cnt)
> {
> class->stats.objs[type] += cnt;
> }
>
> -/* type can be of enum type class_stat_type or fullness_group */
> static inline void class_stat_dec(struct size_class *class,
> int type, unsigned long cnt)
> {
> class->stats.objs[type] -= cnt;
> }
>
> -/* type can be of enum type class_stat_type or fullness_group */
> -static inline unsigned long zs_stat_get(struct size_class *class,
> - int type)
> +static inline unsigned long zs_stat_get(struct size_class *class, int type)
> {
> return class->stats.objs[type];
> }
> @@ -646,16 +637,26 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
> "pages_per_zspage", "freeable");
>
> for (i = 0; i < ZS_SIZE_CLASSES; i++) {
> + int fg;
> +
> class = pool->size_class[i];
>
> if (class->index != i)
> continue;
>
> spin_lock(&pool->lock);
> - class_almost_full = zs_stat_get(class, CLASS_ALMOST_FULL);
> - class_almost_empty = zs_stat_get(class, CLASS_ALMOST_EMPTY);
> - obj_allocated = zs_stat_get(class, OBJ_ALLOCATED);
> - obj_used = zs_stat_get(class, OBJ_USED);
> +
> + /*
> + * Replecate old behaviour for almost_full and almost_empty
> + * stats.
> + */
> + for (fg = ZS_INUSE_RATIO_70; fg <= ZS_INUSE_RATIO_99; fg++)
> + class_almost_full = zs_stat_get(class, fg);
> + for (fg = ZS_INUSE_RATIO_10; fg < ZS_INUSE_RATIO_70; fg++)
> + class_almost_empty = zs_stat_get(class, fg);
Aren't these supposed to be += ?
> +
> + obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
> + obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
> freeable = zs_can_compact(class);
> spin_unlock(&pool->lock);
>
> @@ -723,42 +724,39 @@ static inline void zs_pool_stat_destroy(struct zs_pool *pool)
> }
> #endif
>
> -
> /*
> * For each size class, zspages are divided into different groups
> - * depending on how "full" they are. This was done so that we could
> - * easily find empty or nearly empty zspages when we try to shrink
> - * the pool (not yet implemented). This function returns fullness
> + * depending on their usage ratio. This function returns fullness
> * status of the given page.
> */
> -static enum fullness_group get_fullness_group(struct size_class *class,
> - struct zspage *zspage)
> +static int get_fullness_group(struct size_class *class, struct zspage *zspage)
> {
> - int inuse, objs_per_zspage;
> - enum fullness_group fg;
> + int inuse, objs_per_zspage, ratio;
>
> inuse = get_zspage_inuse(zspage);
> objs_per_zspage = class->objs_per_zspage;
>
> if (inuse == 0)
> - fg = ZS_EMPTY;
> - else if (inuse == objs_per_zspage)
> - fg = ZS_FULL;
> - else if (inuse <= 3 * objs_per_zspage / fullness_threshold_frac)
> - fg = ZS_ALMOST_EMPTY;
> - else
> - fg = ZS_ALMOST_FULL;
> + return ZS_INUSE_RATIO_0;
> + if (inuse == objs_per_zspage)
> + return ZS_INUSE_RATIO_100;
>
> - return fg;
> + ratio = 100 * inuse / objs_per_zspage;
> + /*
> + * Take integer division into consideration: a page with one inuse
> + * object out of 127 possible, will endup having 0 usage ratio,
> + * which is wrong as it belongs in ZS_INUSE_RATIO_10 fullness group.
> + */
> + return ratio / 10 + 1;
> }
>
> /*
> * This function adds the given zspage to the fullness list identified
> - * by <class, fullness_group>.
> + * by <class, fullness group>.
> */
> static void insert_zspage(struct size_class *class,
> struct zspage *zspage,
> - enum fullness_group fullness)
> + int fullness)
> {
> class_stat_inc(class, fullness, 1);
> list_add(&zspage->list, &class->fullness_list[fullness]);
> @@ -766,11 +764,11 @@ static void insert_zspage(struct size_class *class,
>
> /*
> * This function removes the given zspage from the fullness list identified
> - * by <class, fullness_group>.
> + * by <class, fullness group>.
> */
> static void remove_zspage(struct size_class *class,
> struct zspage *zspage,
> - enum fullness_group fullness)
> + int fullness)
> {
> VM_BUG_ON(list_empty(&class->fullness_list[fullness]));
>
> @@ -781,17 +779,16 @@ static void remove_zspage(struct size_class *class,
> /*
> * Each size class maintains zspages in different fullness groups depending
> * on the number of live objects they contain. When allocating or freeing
> - * objects, the fullness status of the page can change, say, from ALMOST_FULL
> - * to ALMOST_EMPTY when freeing an object. This function checks if such
> - * a status change has occurred for the given page and accordingly moves the
> - * page from the freelist of the old fullness group to that of the new
> - * fullness group.
> + * objects, the fullness status of the page can change, for instance, from
> + * INUSE_RATIO_80 to INUSE_RATIO_70 when freeing an object. This function
> + * checks if such a status change has occurred for the given page and
> + * accordingly moves the page from the list of the old fullness group to that
> + * of the new fullness group.
> */
> -static enum fullness_group fix_fullness_group(struct size_class *class,
> - struct zspage *zspage)
> +static int fix_fullness_group(struct size_class *class, struct zspage *zspage)
> {
> int class_idx;
> - enum fullness_group currfg, newfg;
> + int currfg, newfg;
>
> get_zspage_mapping(zspage, &class_idx, &currfg);
> newfg = get_fullness_group(class, zspage);
> @@ -964,7 +961,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
> struct zspage *zspage)
> {
> struct page *page, *next;
> - enum fullness_group fg;
> + int fg;
> unsigned int class_idx;
>
> get_zspage_mapping(zspage, &class_idx, &fg);
> @@ -972,7 +969,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
> assert_spin_locked(&pool->lock);
>
> VM_BUG_ON(get_zspage_inuse(zspage));
> - VM_BUG_ON(fg != ZS_EMPTY);
> + VM_BUG_ON(fg != ZS_INUSE_RATIO_0);
>
> /* Free all deferred handles from zs_free */
> free_handles(pool, class, zspage);
> @@ -990,7 +987,7 @@ static void __free_zspage(struct zs_pool *pool, struct size_class *class,
>
> cache_free_zspage(pool, zspage);
>
> - class_stat_dec(class, OBJ_ALLOCATED, class->objs_per_zspage);
> + class_stat_dec(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
> atomic_long_sub(class->pages_per_zspage,
> &pool->pages_allocated);
> }
> @@ -1011,7 +1008,7 @@ static void free_zspage(struct zs_pool *pool, struct size_class *class,
> return;
> }
>
> - remove_zspage(class, zspage, ZS_EMPTY);
> + remove_zspage(class, zspage, ZS_INUSE_RATIO_0);
> #ifdef CONFIG_ZPOOL
> list_del(&zspage->lru);
> #endif
> @@ -1147,9 +1144,9 @@ static struct zspage *find_get_zspage(struct size_class *class)
> int i;
> struct zspage *zspage;
>
> - for (i = ZS_ALMOST_FULL; i >= ZS_EMPTY; i--) {
> + for (i = ZS_INUSE_RATIO_99; i >= ZS_INUSE_RATIO_0; i--) {
> zspage = list_first_entry_or_null(&class->fullness_list[i],
> - struct zspage, list);
> + struct zspage, list);
> if (zspage)
> break;
> }
> @@ -1508,7 +1505,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
> {
> unsigned long handle, obj;
> struct size_class *class;
> - enum fullness_group newfg;
> + int newfg;
> struct zspage *zspage;
>
> if (unlikely(!size || size > ZS_MAX_ALLOC_SIZE))
> @@ -1530,7 +1527,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
> /* Now move the zspage to another fullness group, if required */
> fix_fullness_group(class, zspage);
> record_obj(handle, obj);
> - class_stat_inc(class, OBJ_USED, 1);
> + class_stat_inc(class, ZS_OBJS_INUSE, 1);
> spin_unlock(&pool->lock);
>
> return handle;
> @@ -1552,8 +1549,8 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
> record_obj(handle, obj);
> atomic_long_add(class->pages_per_zspage,
> &pool->pages_allocated);
> - class_stat_inc(class, OBJ_ALLOCATED, class->objs_per_zspage);
> - class_stat_inc(class, OBJ_USED, 1);
> + class_stat_inc(class, ZS_OBJS_ALLOCATED, class->objs_per_zspage);
> + class_stat_inc(class, ZS_OBJS_INUSE, 1);
>
> /* We completely set up zspage so mark them as movable */
> SetZsPageMovable(pool, zspage);
> @@ -1609,7 +1606,7 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
> struct page *f_page;
> unsigned long obj;
> struct size_class *class;
> - enum fullness_group fullness;
> + int fullness;
>
> if (IS_ERR_OR_NULL((void *)handle))
> return;
> @@ -1624,7 +1621,7 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
> zspage = get_zspage(f_page);
> class = zspage_class(pool, zspage);
>
> - class_stat_dec(class, OBJ_USED, 1);
> + class_stat_dec(class, ZS_OBJS_INUSE, 1);
>
> #ifdef CONFIG_ZPOOL
> if (zspage->under_reclaim) {
> @@ -1642,7 +1639,7 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
> obj_free(class->size, obj, NULL);
>
> fullness = fix_fullness_group(class, zspage);
> - if (fullness == ZS_EMPTY)
> + if (fullness == ZS_INUSE_RATIO_0)
> free_zspage(pool, class, zspage);
>
> spin_unlock(&pool->lock);
> @@ -1824,22 +1821,33 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
> return ret;
> }
>
> -static struct zspage *isolate_zspage(struct size_class *class, bool source)
> +static struct zspage *isolate_src_zspage(struct size_class *class)
> {
> - int i;
> struct zspage *zspage;
> - enum fullness_group fg[2] = {ZS_ALMOST_EMPTY, ZS_ALMOST_FULL};
> + int fg;
>
> - if (!source) {
> - fg[0] = ZS_ALMOST_FULL;
> - fg[1] = ZS_ALMOST_EMPTY;
> + for (fg = ZS_INUSE_RATIO_10; fg <= ZS_INUSE_RATIO_99; fg++) {
> + zspage = list_first_entry_or_null(&class->fullness_list[fg],
> + struct zspage, list);
> + if (zspage) {
> + remove_zspage(class, zspage, fg);
> + return zspage;
> + }
> }
>
> - for (i = 0; i < 2; i++) {
> - zspage = list_first_entry_or_null(&class->fullness_list[fg[i]],
> - struct zspage, list);
> + return zspage;
> +}
> +
> +static struct zspage *isolate_dst_zspage(struct size_class *class)
> +{
> + struct zspage *zspage;
> + int fg;
> +
> + for (fg = ZS_INUSE_RATIO_99; fg >= ZS_INUSE_RATIO_10; fg--) {
> + zspage = list_first_entry_or_null(&class->fullness_list[fg],
> + struct zspage, list);
> if (zspage) {
> - remove_zspage(class, zspage, fg[i]);
> + remove_zspage(class, zspage, fg);
> return zspage;
> }
> }
> @@ -1852,12 +1860,11 @@ static struct zspage *isolate_zspage(struct size_class *class, bool source)
> * @class: destination class
> * @zspage: target page
> *
> - * Return @zspage's fullness_group
> + * Return @zspage's fullness status
> */
> -static enum fullness_group putback_zspage(struct size_class *class,
> - struct zspage *zspage)
> +static int putback_zspage(struct size_class *class, struct zspage *zspage)
> {
> - enum fullness_group fullness;
> + int fullness;
>
> fullness = get_fullness_group(class, zspage);
> insert_zspage(class, zspage, fullness);
> @@ -2121,7 +2128,7 @@ static void async_free_zspage(struct work_struct *work)
> int i;
> struct size_class *class;
> unsigned int class_idx;
> - enum fullness_group fullness;
> + int fullness;
> struct zspage *zspage, *tmp;
> LIST_HEAD(free_pages);
> struct zs_pool *pool = container_of(work, struct zs_pool,
> @@ -2133,7 +2140,7 @@ static void async_free_zspage(struct work_struct *work)
> continue;
>
> spin_lock(&pool->lock);
> - list_splice_init(&class->fullness_list[ZS_EMPTY], &free_pages);
> + list_splice_init(&class->fullness_list[ZS_INUSE_RATIO_0], &free_pages);
> spin_unlock(&pool->lock);
> }
>
> @@ -2142,7 +2149,7 @@ static void async_free_zspage(struct work_struct *work)
> lock_zspage(zspage);
>
> get_zspage_mapping(zspage, &class_idx, &fullness);
> - VM_BUG_ON(fullness != ZS_EMPTY);
> + VM_BUG_ON(fullness != ZS_INUSE_RATIO_0);
> class = pool->size_class[class_idx];
> spin_lock(&pool->lock);
> #ifdef CONFIG_ZPOOL
> @@ -2190,8 +2197,8 @@ static inline void zs_flush_migration(struct zs_pool *pool) { }
> static unsigned long zs_can_compact(struct size_class *class)
> {
> unsigned long obj_wasted;
> - unsigned long obj_allocated = zs_stat_get(class, OBJ_ALLOCATED);
> - unsigned long obj_used = zs_stat_get(class, OBJ_USED);
> + unsigned long obj_allocated = zs_stat_get(class, ZS_OBJS_ALLOCATED);
> + unsigned long obj_used = zs_stat_get(class, ZS_OBJS_INUSE);
>
> if (obj_allocated <= obj_used)
> return 0;
> @@ -2215,7 +2222,7 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> * as well as zpage allocation/free
> */
> spin_lock(&pool->lock);
> - while ((src_zspage = isolate_zspage(class, true))) {
> + while ((src_zspage = isolate_src_zspage(class))) {
> /* protect someone accessing the zspage(i.e., zs_map_object) */
> migrate_write_lock(src_zspage);
>
> @@ -2225,7 +2232,7 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> cc.obj_idx = 0;
> cc.s_page = get_first_page(src_zspage);
>
> - while ((dst_zspage = isolate_zspage(class, false))) {
> + while ((dst_zspage = isolate_dst_zspage(class))) {
> migrate_write_lock_nested(dst_zspage);
>
> cc.d_page = get_first_page(dst_zspage);
> @@ -2250,7 +2257,7 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> putback_zspage(class, dst_zspage);
> migrate_write_unlock(dst_zspage);
>
> - if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
> + if (putback_zspage(class, src_zspage) == ZS_INUSE_RATIO_0) {
> migrate_write_unlock(src_zspage);
> free_zspage(pool, class, src_zspage);
> pages_freed += class->pages_per_zspage;
> @@ -2408,7 +2415,7 @@ struct zs_pool *zs_create_pool(const char *name)
> int pages_per_zspage;
> int objs_per_zspage;
> struct size_class *class;
> - int fullness = 0;
> + int fullness;
>
> size = ZS_MIN_ALLOC_SIZE + i * ZS_SIZE_CLASS_DELTA;
> if (size > ZS_MAX_ALLOC_SIZE)
> @@ -2462,9 +2469,12 @@ struct zs_pool *zs_create_pool(const char *name)
> class->pages_per_zspage = pages_per_zspage;
> class->objs_per_zspage = objs_per_zspage;
> pool->size_class[i] = class;
> - for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
> - fullness++)
> +
> + fullness = ZS_INUSE_RATIO_0;
> + while (fullness < NR_FULLNESS_GROUPS) {
> INIT_LIST_HEAD(&class->fullness_list[fullness]);
> + fullness++;
> + }
>
> prev_class = class;
> }
> @@ -2510,11 +2520,12 @@ void zs_destroy_pool(struct zs_pool *pool)
> if (class->index != i)
> continue;
>
> - for (fg = ZS_EMPTY; fg < NR_ZS_FULLNESS; fg++) {
> - if (!list_empty(&class->fullness_list[fg])) {
> - pr_info("Freeing non-empty class with size %db, fullness group %d\n",
> - class->size, fg);
> - }
> + for (fg = ZS_INUSE_RATIO_0; fg < NR_FULLNESS_GROUPS; fg++) {
> + if (list_empty(&class->fullness_list[fg]))
> + continue;
> +
> + pr_err("Class-%d fullness group %d is not empty\n",
> + class->size, fg);
> }
> kfree(class);
> }
> @@ -2616,7 +2627,7 @@ static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
> unsigned long handle;
> struct zspage *zspage;
> struct page *page;
> - enum fullness_group fullness;
> + int fullness;
>
> /* Lock LRU and fullness list */
> spin_lock(&pool->lock);
> @@ -2686,7 +2697,7 @@ static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
> * while the page is removed from the pool. Fix it
> * up for the check in __free_zspage().
> */
> - zspage->fullness = ZS_EMPTY;
> + zspage->fullness = ZS_INUSE_RATIO_0;
>
> __free_zspage(pool, class, zspage);
> spin_unlock(&pool->lock);
> --
> 2.40.0.rc0.216.gc4246ad0f0-goog
>
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