From: Michal Hocko <mhocko@kernel.org>
To: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [QUESTIONS] THP allocation in NUMA fault migration path
Date: Thu, 18 Apr 2019 08:32:18 +0200 [thread overview]
Message-ID: <20190418063218.GA6567@dhcp22.suse.cz> (raw)
In-Reply-To: <aa34f38e-5e55-bdb2-133c-016b91245533@linux.alibaba.com>
On Wed 17-04-19 21:15:41, Yang Shi wrote:
> Hi folks,
>
>
> I noticed that there might be new THP allocation in NUMA fault migration
> path (migrate_misplaced_transhuge_page()) even when THP is disabled (set to
> "never"). When THP is set to "never", there should be not any new THP
> allocation, but the migration path is kind of special. So I'm not quite sure
> if this is the expected behavior or not?
>
>
> And, it looks this allocation disregards defrag setting too, is this
> expected behavior too?H
Could you point to the specific code? But in general the miTgration path
should allocate the memory matching the migration origin. If the origin
was a THP then I find it quite natural if the target was a huge page as
well. How hard the allocation should try is another question and I
suspect we do want to obedy the defrag setting.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-04-18 6:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-18 4:15 Yang Shi
2019-04-18 6:32 ` Michal Hocko [this message]
2019-04-18 16:18 ` Yang Shi
2019-04-19 11:13 ` Mel Gorman
2019-04-19 16:28 ` Yang Shi
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