On Wed 14-08-19 14:49:18, Vlastimil Babka wrote: > On 8/9/19 8:26 PM, Yang Shi wrote: > > Here the new counter is introduced for patch 2/2 to account deferred > > split THPs into available memory since NR_ANON_THPS may contain > > non-deferred split THPs. > > > > I could use an internal counter for deferred split THPs, but if it is > > accounted by mod_node_page_state, why not just show it in /proc/meminfo? > > The answer to "Why not" is that it becomes part of userspace API (btw this > patchset should have CC'd linux-api@ - please do for further iterations) and > even if the implementation detail of deferred splitting might change in the > future, we'll basically have to keep the counter (even with 0 value) in > /proc/meminfo forever. > > Also, quite recently we have added the following counter: > > KReclaimable: Kernel allocations that the kernel will attempt to reclaim > under memory pressure. Includes SReclaimable (below), and other > direct allocations with a shrinker. > > Although THP allocations are not exactly "kernel allocations", once they are > unmapped, they are in fact kernel-only, so IMHO it wouldn't be a big stretch to > add the lazy THP pages there? That would indeed fit in much better than a dedicated counter. -- Michal Hocko SUSE Labs
