Re: [PATCHv3 2/4] zsmalloc: fine-grained inuse ratio based fullness grouping
From: Yosry Ahmed
Date: Fri Mar 03 2023 - 11:59:40 EST
On Fri, Mar 3, 2023 at 8:55 AM Yosry Ahmed <yosryahmed@xxxxxxxxxx> wrote:
>
> Hi Sergey,
>
> Thanks for working on this!
>
> On Thu, Mar 2, 2023 at 11:31 PM Sergey Senozhatsky
> <senozhatsky@xxxxxxxxxxxx> 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@xxxxxxxxxxxx>
> > ---
> > 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 += ?
Looks like they are removed by a following patch anyway.
>
> > +
> > + 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
> >