[PATCH v5 04/12] zsmalloc: keep max_object in size_class

Minchan Kim
2016-05-09T02:21:57Z

Every zspage in a size_class has same number of max objects so
we could move it to a size_class.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
mm/zsmalloc.c | 32 +++++++++++++++-----------------
1 file changed, 15 insertions(+), 17 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 3d6d3dae505a..3c2574be8cee 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -32,8 +32,6 @@
* page->freelist: points to the first free object in zspage.
* Free objects are linked together using in-place
* metadata.
- * page->objects: maximum number of objects we can store in this
- * zspage (class->zspage_order * PAGE_SIZE / class->size)
* page->lru: links together first pages of various zspages.
* Basically forming list of zspages in a fullness group.
* page->mapping: class index and fullness group of the zspage
@@ -211,6 +209,7 @@ struct size_class {
* of ZS_ALIGN.
*/
int size;
+ int objs_per_zspage;
unsigned int index;

struct zs_size_stat stats;
@@ -627,21 +626,22 @@ static inline void zs_pool_stat_destroy(struct zs_pool *pool)
* the pool (not yet implemented). This function returns fullness
* status of the given page.
*/
-static enum fullness_group get_fullness_group(struct page *first_page)
+static enum fullness_group get_fullness_group(struct size_class *class,
+ struct page *first_page)
{
- int inuse, max_objects;
+ int inuse, objs_per_zspage;
enum fullness_group fg;

VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

inuse = first_page->inuse;
- max_objects = first_page->objects;
+ objs_per_zspage = class->objs_per_zspage;

if (inuse == 0)
fg = ZS_EMPTY;
- else if (inuse == max_objects)
+ else if (inuse == objs_per_zspage)
fg = ZS_FULL;
- else if (inuse <= 3 * max_objects / fullness_threshold_frac)
+ else if (inuse <= 3 * objs_per_zspage / fullness_threshold_frac)
fg = ZS_ALMOST_EMPTY;
else
fg = ZS_ALMOST_FULL;
@@ -728,7 +728,7 @@ static enum fullness_group fix_fullness_group(struct size_class *class,
enum fullness_group currfg, newfg;

get_zspage_mapping(first_page, &class_idx, &currfg);
- newfg = get_fullness_group(first_page);
+ newfg = get_fullness_group(class, first_page);
if (newfg == currfg)
goto out;

@@ -1011,9 +1011,6 @@ static struct page *alloc_zspage(struct size_class *class, gfp_t flags)
init_zspage(class, first_page);

first_page->freelist = location_to_obj(first_page, 0);
- /* Maximum number of objects we can store in this zspage */
- first_page->objects = class->pages_per_zspage * PAGE_SIZE / class->size;
-
error = 0; /* Success */

cleanup:
@@ -1241,11 +1238,11 @@ static bool can_merge(struct size_class *prev, int size, int pages_per_zspage)
return true;
}

-static bool zspage_full(struct page *first_page)
+static bool zspage_full(struct size_class *class, struct page *first_page)
{
VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);

- return first_page->inuse == first_page->objects;
+ return first_page->inuse == class->objs_per_zspage;
}

unsigned long zs_get_total_pages(struct zs_pool *pool)
@@ -1631,7 +1628,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
}

/* Stop if there is no more space */
- if (zspage_full(d_page)) {
+ if (zspage_full(class, d_page)) {
unpin_tag(handle);
ret = -ENOMEM;
break;
@@ -1690,7 +1687,7 @@ static enum fullness_group putback_zspage(struct zs_pool *pool,
{
enum fullness_group fullness;

- fullness = get_fullness_group(first_page);
+ fullness = get_fullness_group(class, first_page);
insert_zspage(class, fullness, first_page);
set_zspage_mapping(first_page, class->index, fullness);

@@ -1939,8 +1936,9 @@ struct zs_pool *zs_create_pool(const char *name)
class->size = size;
class->index = i;
class->pages_per_zspage = pages_per_zspage;
- if (pages_per_zspage == 1 &&
- get_maxobj_per_zspage(size, pages_per_zspage) == 1)
+ class->objs_per_zspage = class->pages_per_zspage *
+ PAGE_SIZE / class->size;
+ if (pages_per_zspage == 1 && class->objs_per_zspage == 1)
class->huge = true;
spin_lock_init(&class->lock);
pool->size_class[i] = class;
--
1.9.1