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Date: Wed, 17 Oct 2018 09:08:25 +0200
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH 1/2] mm: thp:  relax __GFP_THISNODE for MADV_HUGEPAGE
 mappings
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To: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>, Mel Gorman <mgorman@suse.de>, David Rientjes <rientjes@google.com>, Vlastimil Babka <vbabka@suse.cz>, Andrea Argangeli <andrea@kernel.org>, Zi Yan <zi.yan@cs.rutgers.edu>, Stefan Priebe - Profihost AG <s.priebe@profihost.ag>, "Kirill A. Shutemov" <kirill@shutemov.name>, linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>, Stable tree <stable@vger.kernel.org>

On Tue 16-10-18 16:16:43, Andrew Morton wrote:
> On Tue, 16 Oct 2018 19:11:49 -0400 Andrea Arcangeli <aarcange@redhat.com> wrote:
> 
> > This was a severe regression
> > compared to previous kernels that made important workloads unusable
> > and it starts when __GFP_THISNODE was added to THP allocations under
> > MADV_HUGEPAGE. It is not a significant risk to go to the previous
> > behavior before __GFP_THISNODE was added, it worked like that for
> > years.@s1@s2@s1
> 
> 5265047ac301 ("mm, thp: really limit transparent hugepage allocation to
> local node") was April 2015.  That's a long time for a "severe
> regression" to go unnoticed?

Well, it gets some time to adopt changes in enterprise and we start
seeing people reporting this issue. That is why I believe we should
start with something really simple and stable tree backportable first
and then build something more complex on top.
-- 
Michal Hocko
SUSE Labs