lkml.org 
[lkml]   [2017]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages
On Tue 17-10-17 22:41:08, Michael Ellerman wrote:
> Michal Hocko <mhocko@kernel.org> writes:
>
> > From: Michal Hocko <mhocko@suse.com>
> >
> > Michael has noticed that the memory offline tries to migrate kernel code
> > pages when doing
> > echo 0 > /sys/devices/system/memory/memory0/online
> >
> > The current implementation will fail the operation after several failed
> > page migration attempts but we shouldn't even attempt to migrate
> > that memory and fail right away because this memory is clearly not
> > migrateable. This will become a real problem when we drop the retry loop
> > counter resp. timeout.
> >
> > The real problem is in has_unmovable_pages in fact. We should fail if
> > there are any non migrateable pages in the area. In orther to guarantee
> > that remove the migrate type checks because MIGRATE_MOVABLE is not
> > guaranteed to contain only migrateable pages. It is merely a heuristic.
> > Similarly MIGRATE_CMA does guarantee that the page allocator doesn't
> > allocate any non-migrateable pages from the block but CMA allocations
> > themselves are unlikely to migrateable. Therefore remove both checks.
> >
> > Reported-by: Michael Ellerman <mpe@ellerman.id.au>
> > Signed-off-by: Michal Hocko <mhocko@suse.com>
>
> Thanks, that works for me.
>
> Tested-by: Michael Ellerman <mpe@ellerman.id.au>

Thanks a lot Michael!

Andrew, could you add these two patches and merge them before
mm-memory_hotplug-do-not-fail-offlining-too-early.patch? Or should I
rather repost the full series (including 2 already merged patches?
again?
--
Michal Hocko
SUSE Labs

\
 
 \ /
  Last update: 2017-10-17 14:03    [W:0.154 / U:0.088 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site