On (24/02/19 13:33), Chengming Zhou wrote:
> static void migrate_write_unlock(struct zspage *zspage)
> {
> write_unlock(&zspage->lock);
> @@ -2003,19 +1997,17 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> dst_zspage = isolate_dst_zspage(class);
> if (!dst_zspage)
> break;
> - migrate_write_lock(dst_zspage);
> }
>
> src_zspage = isolate_src_zspage(class);
> if (!src_zspage)
> break;
>
> - migrate_write_lock_nested(src_zspage);
> -
> + migrate_write_lock(src_zspage);
> migrate_zspage(pool, src_zspage, dst_zspage);
> - fg = putback_zspage(class, src_zspage);
> migrate_write_unlock(src_zspage);
>
> + fg = putback_zspage(class, src_zspage);
Hmm. Lockless putback doesn't look right to me. We modify critical
zspage fileds in putback_zspage().
> if (fg == ZS_INUSE_RATIO_0) {
> free_zspage(pool, class, src_zspage);
> pages_freed += class->pages_per_zspage;
> @@ -2025,7 +2017,6 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> if (get_fullness_group(class, dst_zspage) == ZS_INUSE_RATIO_100
> || spin_is_contended(&pool->lock)) {
> putback_zspage(class, dst_zspage);
> - migrate_write_unlock(dst_zspage);
> dst_zspage = NULL;
>
> spin_unlock(&pool->lock);
> @@ -2034,15 +2025,12 @@ static unsigned long __zs_compact(struct zs_pool *pool,
> }
> }
>
> - if (src_zspage) {
> + if (src_zspage)
> putback_zspage(class, src_zspage);
> - migrate_write_unlock(src_zspage);
> - }
>
> - if (dst_zspage) {
> + if (dst_zspage)
> putback_zspage(class, dst_zspage);
> - migrate_write_unlock(dst_zspage);
> - }
