Re: [PATCH v20 07/20] mm/vmscan: remove unnecessary lruvec adding

Johannes Weiner
2020-11-02T14:22:21Z

On Thu, Oct 29, 2020 at 06:44:52PM +0800, Alex Shi wrote:
> We don't have to add a freeable page into lru and then remove from it.
> This change saves a couple of actions and makes the moving more clear.
>
> The SetPageLRU needs to be kept before put_page_testzero for list
> integrity, otherwise:
>
> #0 move_pages_to_lru #1 release_pages
> if !put_page_testzero
> if (put_page_testzero())
> !PageLRU //skip lru_lock
> SetPageLRU()
> list_add(&page->lru,)
> list_add(&page->lru,)
>
> [akpm@linux-foundation.org: coding style fixes]
> Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
> Acked-by: Hugh Dickins <hughd@google.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: linux-mm@kvack.org
> Cc: linux-kernel@vger.kernel.org

Acked-by: Johannes Weiner <hannes@cmpxchg.org>