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Date:   Fri, 17 Apr 2020 12:06:33 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     "Huang, Ying" <ying.huang@intel.com>
Cc:     Mel Gorman <mgorman@techsingularity.net>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@surriel.com>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Tejun Heo <tj@kernel.org>, Dave Hansen <dave.hansen@intel.com>,
        Tim Chen <tim.c.chen@intel.com>,
        Aubrey Li <aubrey.li@intel.com>
Subject: Re: [RFC] autonuma: Support to scan page table asynchronously
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On Thu, Apr 16, 2020 at 09:24:35AM +0800, Huang, Ying wrote:
> Peter Zijlstra <peterz@infradead.org> writes:
> 
> > On Tue, Apr 14, 2020 at 01:06:46PM +0100, Mel Gorman wrote:
> >> While it's just an opinion, my preference would be to focus on reducing
> >> the cost and amount of scanning done -- particularly for threads.
> >
> > This; I really don't believe in those back-charging things, esp. since
> > not having cgroups or having multiple applications in a single cgroup is
> > a valid setup.
> 
> Technically, it appears possible to back-charge the CPU time to the
> process/thread directly (not the cgroup).

I've yet to see a sane proposal there. What we're not going to do is
make regular task accounting more expensive than it already is.