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Date: Mon, 29 Oct 2018 10:00:35 +0100
From: Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH 1/2] mm: thp:  relax __GFP_THISNODE for MADV_HUGEPAGE
 mappings
Message-ID: <20181029090035.GE32673@dhcp22.suse.cz>
References: <20180925120326.24392-1-mhocko@kernel.org>
 <20180925120326.24392-2-mhocko@kernel.org>
 <20181029051752.GB16399@350D>
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To: Balbir Singh <bsingharora@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>, David Rientjes <rientjes@google.com>, 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>, Andrea Arcangeli <aarcange@redhat.com>, Stable tree <stable@vger.kernel.org>

On Mon 29-10-18 16:17:52, Balbir Singh wrote:
[...]
> I wonder if alloc_pool_huge_page() should also trim out it's logic
> of __GFP_THISNODE for the same reasons as mentioned here. I like
> that we round robin to alloc the pool pages, but __GFP_THISNODE
> might be an overkill for that case as well.

alloc_pool_huge_page uses __GFP_THISNODE for a different reason than
THP. We really do want to allocated for a per-node pool. THP can
fallback or use a different node.

These hugetlb allocations might be disruptive and that is an expected
behavior because this is an explicit requirement from an admin to
pre-allocate large pages for the future use. __GFP_RETRY_MAYFAIL just
underlines that requirement.

Maybe the compaction logic could be improved and that might be a shared
goal with future changes though.
-- 
Michal Hocko
SUSE Labs