On Fri, Jan 26, 2024 at 8:34 AM Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > > On Wed, Jan 24, 2024 at 09:46:23AM -0800, T.J. Mercier wrote: > > In the meantime, instead of a revert how about changing the batch size > > geometrically instead of the SWAP_CLUSTER_MAX constant: > > > > reclaimed = try_to_free_mem_cgroup_pages(memcg, > > - min(nr_to_reclaim - > > nr_reclaimed, SWAP_CLUSTER_MAX), > > + (nr_to_reclaim - nr_reclaimed)/2, > > GFP_KERNEL, reclaim_options); > > > > I think that should address the overreclaim concern (it was mentioned > > that the upper bound of overreclaim was 2 * request), and this should > > also increase the reclaim rate for root reclaim with MGLRU closer to > > what it was before. > > Hahaha. Would /4 work for you? > > I genuinely think the idea is worth a shot. /4 would give us a bit > more margin for error, since the bailout/fairness cutoffs have changed > back and forth over time. And it should still give you a reasonable > convergence on MGLRU. > > try_to_free_reclaim_pages() already does max(nr_to_reclaim, > SWAP_CLUSTER_MAX) which will avoid the painful final approach loops > the integer division would produce on its own. > > Please add a comment mentioning the compromise between the two reclaim > implementations though. I'll try it out and get back to you. :)
