On (24/02/20 12:51), Chengming Zhou wrote:
> On 2024/2/20 12:48, Sergey Senozhatsky wrote:
> > 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().
>
> Which I think is protected by pool->lock, right? We already held it.
Not really. We have, for example, the following patterns:
get_zspage_mapping()
spin_lock(&pool->lock)
