Re: [PATCH 6/7] mm, vmscan: enhance mm_vmscan_lru_shrink_inactive tracepoint

From: Hillf Danton
Date: Thu Dec 29 2016 - 03:11:51 EST

On Wednesday, December 28, 2016 11:31 PM Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
> mm_vmscan_lru_shrink_inactive will currently report the number of
> scanned and reclaimed pages. This doesn't give us an idea how the
> reclaim went except for the overall effectiveness though. Export
> and show other counters which will tell us why we couldn't reclaim
> some pages.
> - nr_dirty, nr_writeback, nr_congested and nr_immediate tells
> us how many pages are blocked due to IO
> - nr_activate tells us how many pages were moved to the active
> list
> - nr_ref_keep reports how many pages are kept on the LRU due
> to references (mostly for the file pages which are about to
> go for another round through the inactive list)
> - nr_unmap_fail - how many pages failed to unmap
> All these are rather low level so they might change in future but the
> tracepoint is already implementation specific so no tools should be
> depending on its stability.
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
> ---
Acked-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>