75% of the PAGE_SIZE is not a correct threshold to store uncompressed
pages in zs_page as this must be changed if the maximum pages stored
in zspage changes. Instead using zs classes, we can set the correct
threshold irrespective of the maximum pages stored in zspage.
Tested on ARM:
Before Patch:
class size obj_allocated obj_used pages_used
....
190 3072 6744 6724 5058
202 3264 90 87 72
254 4096 11886 11886 11886
Total 123251 120511 55076
After Patch:
class size obj_allocated obj_used pages_used
...
190 3072 6368 6326 4776
202 3264 2205 2197 1764
254 4096 12624 12624 12624
Total 125655 122045 56541
Signed-off-by: Gopi Sai Teja <gopi.st@xxxxxxxxxxx>
---
v1 -> v2: Earlier, threshold to store uncompressed page is set
to 80% of PAGE_SIZE and now zsmalloc classes is used to set the
threshold.
drivers/block/zram/zram_drv.c | 2 +-
include/linux/zsmalloc.h | 1 +
mm/zsmalloc.c | 13 +++++++++++++
3 files changed, 15 insertions(+), 1 deletion(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index d70eba3..dda0ef8 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -965,7 +965,7 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec,
return ret;
}
- if (unlikely(comp_len > max_zpage_size)) {
+ if (unlikely(comp_len > zs_max_zpage_size(zram->mem_pool))) {
if (zram_wb_enabled(zram) && allow_wb) {
zcomp_stream_put(zram->comp);
ret = write_to_bdev(zram, bvec, index, bio, &element);
diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
index 57a8e98..0b09aa5 100644
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -54,5 +54,6 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
unsigned long zs_get_total_pages(struct zs_pool *pool);
unsigned long zs_compact(struct zs_pool *pool);
+unsigned int zs_max_zpage_size(struct zs_pool *pool);
void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats);
#endif
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 685049a..5b434ab 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -261,6 +261,7 @@ struct zs_pool {
* and unregister_shrinker() will not Oops.
*/
bool shrinker_enabled;
+ unsigned short max_zpage_size;
#ifdef CONFIG_ZSMALLOC_STAT
struct dentry *stat_dentry;
#endif
@@ -318,6 +319,11 @@ static void init_deferred_free(struct zs_pool *pool) {}
static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
#endif
+unsigned int zs_max_zpage_size(struct zs_pool *pool)
+{
+ return pool->max_zpage_size;
+}
+
static int create_cache(struct zs_pool *pool)
{
pool->handle_cachep = kmem_cache_create("zs_handle", ZS_HANDLE_SIZE,
@@ -2368,6 +2374,8 @@ struct zs_pool *zs_create_pool(const char *name)
if (create_cache(pool))
goto err;
+ pool->max_zpage_size = 0;
+
/*
* Iterate reversely, because, size of size_class that we want to use
* for merging should be larger or equal to current size.
@@ -2411,6 +2419,11 @@ struct zs_pool *zs_create_pool(const char *name)
class->objs_per_zspage = objs_per_zspage;
spin_lock_init(&class->lock);
pool->size_class[i] = class;
+
+ if (!pool->max_zpage_size &&
+ pages_per_zspage < objs_per_zspage)
+ pool->max_zpage_size = class->size - ZS_HANDLE_SIZE;
+
for (fullness = ZS_EMPTY; fullness < NR_ZS_FULLNESS;
fullness++)
INIT_LIST_HEAD(&class->fullness_list[fullness]);
--
1.9.1
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