Re: [PATCH v5 2/4] mm: convert zone->managed_pages to atomic variable

[Pavel Tatashin]

On 18-11-13 12:03:08, Arun KS wrote:
> totalram_pages, zone->managed_pages and totalhigh_pages updates
> are protected by managed_page_count_lock, but readers never care
> about it. Convert these variables to atomic to avoid readers
> potentially seeing a store tear.
> 
> This patch converts zone->managed_pages. Subsequent patches will
> convert totalram_panges, totalhigh_pages and eventually
> managed_page_count_lock will be removed.
> 
> Main motivation was that managed_page_count_lock handling was
> complicating things. It was discussed in length here,
> https://lore.kernel.org/patchwork/patch/995739/#1181785
> So it seemes better to remove the lock and convert variables
> to atomic, with preventing poteintial store-to-read tearing as
> a bonus.
> 
> Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
> Suggested-by: Vlastimil Babka <vbabka@xxxxxxx>
> Signed-off-by: Arun KS <arunks@xxxxxxxxxxxxxx>
> Reviewed-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> Acked-by: Michal Hocko <mhocko@xxxxxxxx>
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>