On Fri 13-03-20 17:00:56, Huang, Ying wrote: > From: Huang Ying <ying.huang@xxxxxxxxx> > > Some comments for MADV_FREE is revised and added to help people understand the > MADV_FREE code, especially the page flag, PG_swapbacked. This makes > page_is_file_cache() isn't consistent with its comments. So the function is > renamed to page_is_file_lru() to make them consistent again. All these are put > in one patch as one logical change. > > Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx> > Suggested-by: David Hildenbrand <david@xxxxxxxxxx> > Suggested-by: Johannes Weiner <hannes@xxxxxxxxxxx> > Suggested-by: David Rientjes <rientjes@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Hugh Dickins <hughd@xxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Although I would rephrased this a bit > + * PG_swapbacked is cleared if the page is page cache page backed by a regular > + * file system or anonymous page lazily freed (e.g. via MADV_FREE). It is set > + * if the page is normal anonymous page, tmpfs or otherwise RAM or swap backed. > + * PG_swapbacked is set when a page uses swap as a backing storage. This are usually PageAnon or shmem pages but please note that even anonymous pages might lose their PG_swapbacked flag when they simply can be dropped (e.g. as a result of MADV_FREE). -- Michal Hocko SUSE Labs
