On Mon, 2019-01-28 at 11:54 -0800, Andrew Morton wrote: > On Mon, 28 Jan 2019 14:35:35 -0500 Rik van Riel <[email protected]> > wrote: > > > /* > > * Make sure we apply some minimal pressure on default priority > > - * even on small cgroups. Stale objects are not only consuming > > memory > > + * even on small cgroups, by accumulating pressure across > > multiple > > + * slab shrinker runs. Stale objects are not only consuming > > memory > > * by themselves, but can also hold a reference to a dying > > cgroup, > > * preventing it from being reclaimed. A dying cgroup with all > > * corresponding structures like per-cpu stats and kmem caches > > * can be really big, so it may lead to a significant waste of > > memory. > > */ > > - delta = max_t(unsigned long long, delta, min(freeable, > > batch_size)); > > + if (!delta) { > > + shrinker->small_scan += freeable; > > + > > + delta = shrinker->small_scan >> priority; > > + shrinker->small_scan -= delta << priority; > > + > > + delta *= 4; > > + do_div(delta, shrinker->seeks); > > What prevents shrinker->small_scan from over- or underflowing over > time?
We only go into this code path if delta >> DEF_PRIORITY is zero. That is, freeable is smaller than 4096. > I'll add this: > whitespace fixes, per Roman Awesome, thank you! -- All Rights Reversed.
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