On Thu, Sep 08, 2022 at 06:33:24PM +0800, Zhenhua Huang wrote: > Remove an expensive and unnecessary operation as PCP pages are safely > skipped when reading page owner. PCP pages can be skipped because > PAGE_EXT_OWNER_ALLOCATED is cleared. > > With draining PCP pages, these pages are moved to buddy list so they > can be identified as buddy pages and skipped quickly. Although it improved > efficiency of PFN walker, the drain is guaranteed expensive that is > unlikely to be offset by a slight increase in efficiency when skipping > free pages. > > PAGE_EXT_OWNER_ALLOCATED is cleared in the page owner reset path below: > free_unref_page > -> free_unref_page_prepare > -> free_pcp_prepare > -> free_pages_prepare which do page owner > reset > -> free_unref_page_commit which add pages into pcp list > > Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> > Signed-off-by: Zhenhua Huang <quic_zhenhuah@xxxxxxxxxxx> Should be; Signed-off-by: Zhenhua Huang <quic_zhenhuah@xxxxxxxxxxx> Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Otherwise looks good! -- Mel Gorman SUSE Labs
