On (22/10/27 11:27), Nhat Pham wrote:
> +
> +static int zs_zpool_shrink(void *pool, unsigned int pages,
> + unsigned int *reclaimed)
> +{
> + unsigned int total = 0;
> + int ret = -EINVAL;
> +
> + while (total < pages) {
> + ret = zs_reclaim_page(pool, 8);
> + if (ret < 0)
> + break;
> + total++;
> + }
> +
> + if (reclaimed)
> + *reclaimed = total;
> +
> + return ret;
> +}
The name collides with shrinker callbacks (compaction). That's a bit
confusing, took me some time.
> @@ -482,6 +504,7 @@ static struct zpool_driver zs_zpool_driver = {
> .malloc_support_movable = true,
> .malloc = zs_zpool_malloc,
> .free = zs_zpool_free,
> + .shrink = zs_zpool_shrink,
> .map = zs_zpool_map,
> .unmap = zs_zpool_unmap,
> .total_size = zs_zpool_total_size,
> @@ -955,6 +978,21 @@ static int trylock_zspage(struct zspage *zspage)
> return 0;
> }
[..]
> +#ifdef CONFIG_ZPOOL
> +static int zs_reclaim_page(struct zs_pool *pool, unsigned int retries)
> +{
> + int i, obj_idx, ret = 0;
> + unsigned long handle;
> + struct zspage *zspage;
> + struct page *page;
> + enum fullness_group fullness;
> +
> + /* Lock LRU and fullness list */
> + spin_lock(&pool->lock);
> + if (!pool->ops || !pool->ops->evict || list_empty(&pool->lru) ||
You don't need pool->lock for pool->ops/pool->ops->evict checks.
But, more importantly, I don't understand why is it even checked here?
Why do we use ops->evict? Why cannot we call into zsmalloc evict
directly? All of these are statically defined in zsmalloc, just don't
provide .shrink if !define CONFIG_ZPOOL? Under what circumstances
zsmalloc can provide .shrink but no ->evict?
