On Thu, Jul 11, 2019 at 2:43 AM Sebastian Andrzej Siewior
<bigeasy@xxxxxxxxxxxxx> wrote:
>
> On 2019-07-10 11:21:19 [-0700], Yang Shi wrote:
> >
> > compaction should not isolate unevictable pages unless you have
> > /proc/sys/vm/compact_unevictable_allowed set.
>
> Thank you. This is enabled by default. The documentation for this says
> | … compaction is allowed to examine the unevictable lru (mlocked pages) for
> | pages to compact.…
>
> so it is actually clear once you know where to look.
> If I read this correct, the default behavior was to ignore mlock()ed
> pages for compaction then commit
> 5bbe3547aa3ba ("mm: allow compaction of unevictable pages")
Yes, before this commit compaction doesn't migrate unevictable pages.
But, other types of migration always do.
>
> came along in v4.1-rc1 and changed that behaviour. Is it too late to
> flip it back?
Disabling it via proc knob isn't fine?
>
> Sebastian
