On 4/22/21 1:14 PM, Mel Gorman wrote: > The per-cpu page allocator lists and the per-cpu vmstat deltas are stored > in the same struct per_cpu_pages even though vmstats have no direct impact > on the per-cpu page lists. This is inconsistent because the vmstats for a > node are stored on a dedicated structure. The bigger issue is that the > per_cpu_pages structure is not cache-aligned and stat updates either > cache conflict with adjacent per-cpu lists incurring a runtime cost or > padding is required incurring a memory cost. > > This patch splits the per-cpu pagelists and the vmstat deltas into separate > structures. It's mostly a mechanical conversion but some variable renaming > is done to clearly distinguish the per-cpu pages structure (pcp) from > the vmstats (pzstats). > > Superficially, this appears to increase the size of the per_cpu_pages > structure but the movement of expire fills a structure hole so there is > no impact overall. > > [lkp@xxxxxxxxx: Check struct per_cpu_zonestat has a non-zero size] > [vbabka@xxxxxxx: Init zone->per_cpu_zonestats properly] > Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
