On Mon 10-06-19 20:12:49, Minchan Kim wrote:
> The local variable references in shrink_page_list is PAGEREF_RECLAIM_CLEAN
> as default. It is for preventing to reclaim dirty pages when CMA try to
> migrate pages. Strictly speaking, we don't need it because CMA didn't allow
> to write out by .may_writepage = 0 in reclaim_clean_pages_from_list.
>
> Moreover, it has a problem to prevent anonymous pages's swap out even
> though force_reclaim = true in shrink_page_list on upcoming patch.
> So this patch makes references's default value to PAGEREF_RECLAIM and
> rename force_reclaim with ignore_references to make it more clear.
>
> This is a preparatory work for next patch.
>
> * RFCv1
> * use ignore_referecnes as parameter name - hannes
>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
The code path is quite tricky to follow but the patch looks OK to me.
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
> mm/vmscan.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 84dcb651d05c..0973a46a0472 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1102,7 +1102,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> struct scan_control *sc,
> enum ttu_flags ttu_flags,
> struct reclaim_stat *stat,
> - bool force_reclaim)
> + bool ignore_references)
> {
> LIST_HEAD(ret_pages);
> LIST_HEAD(free_pages);
> @@ -1116,7 +1116,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> struct address_space *mapping;
> struct page *page;
> int may_enter_fs;
> - enum page_references references = PAGEREF_RECLAIM_CLEAN;
> + enum page_references references = PAGEREF_RECLAIM;
> bool dirty, writeback;
> unsigned int nr_pages;
>
> @@ -1247,7 +1247,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> }
> }
>
> - if (!force_reclaim)
> + if (!ignore_references)
> references = page_check_references(page, sc);
>
> switch (references) {
> --
> 2.22.0.rc2.383.gf4fbbf30c2-goog
--
Michal Hocko
SUSE Labs
