Re: [PATCH v2 1/2] mm: compaction: consider the number of scanning compound pages in isolate fail path

[Vlastimil Babka <vbabka@suse.cz>]

On 3/16/23 12:06, Baolin Wang wrote:
> The commit b717d6b93b54 ("mm: compaction: include compound page count
> for scanning in pageblock isolation") had added compound page statistics
> for scanning in pageblock isolation, to make sure the number of scanned
> pages are always larger than the number of isolated pages when isolating
> mirgratable or free pageblock.
> 
> However, when failed to isolate the pages when scanning the mirgratable or
> free pageblock, the isolation failure path did not consider the scanning
> statistics of the compound pages, which can show the incorrect number of
> scanned pages in tracepoints or the vmstats to make people confusing about
> the page scanning pressure in memory compaction.
> 
> Thus we should take into account the number of scanning pages when failed
> to isolate the compound pages to make the statistics accurate.
> 
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

Thanks!