From: Ingo Molnar <mingo@kernel.org>
To: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
mingo@redhat.com, linux-kernel@vger.kernel.org,
aarcange@redhat.com, Michel Lespinasse <walken@google.com>
Subject: Re: [PATCH 4/2] numa, mm: Rename the PROT_NONE fault handling functions
Date: Sun, 21 Oct 2012 15:43:41 +0200 [thread overview]
Message-ID: <20121021134341.GA23820@gmail.com> (raw)
In-Reply-To: <20121021132921.GA23425@gmail.com>
* Ingo Molnar <mingo@kernel.org> wrote:
> > Michel indicated that he does not use PROT_NONE for his
> > working set estimation code, but instead checks the accessed
> > bits in the page tables.
>
> The pte_young() WSS method has a couple of fundamental
> limitations:
>
> - it doesn't work with shared memory very well, the pte is per
> mapping, not per page. The PROT_NONE method instruments the
> physical page in essence.
>
> - it does not tell us which task touched the pte, in a
> multi-threaded program
>
> So like Peter I'd too expect these new WSS methods to eventually
> be picked up for any serious WSS work.
Nevertheless lets wait and see until it actually happens - and
meanwhile the prot_none namings are confusing.
So I've applied your patch as-is, with two more (new) usage
sites converted as well. Will push it out after a bit of
testing.
Thanks,
Ingo
next prev parent reply other threads:[~2012-10-21 13:43 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-18 21:18 [PATCH 0/2] minor NUMA cleanups & documentation Rik van Riel
2012-10-18 21:19 ` [PATCH 1/2] add credits for NUMA placement Rik van Riel
2012-10-19 11:41 ` Peter Zijlstra
2012-10-19 12:02 ` [tip:numa/core] numa: Add " tip-bot for Rik van Riel
2012-10-28 17:11 ` [tip:numa/core] sched, numa, mm: " tip-bot for Rik van Riel
2012-11-13 15:31 ` tip-bot for Rik van Riel
2012-11-13 17:23 ` tip-bot for Rik van Riel
2012-11-19 19:46 ` tip-bot for Rik van Riel
2012-10-18 21:20 ` [PATCH 2/2] rename NUMA fault handling functions Rik van Riel
2012-10-19 11:41 ` Peter Zijlstra
2012-10-19 14:07 ` Rik van Riel
2012-10-19 20:54 ` Ingo Molnar
2012-10-21 12:50 ` [PATCH 4/2] numa, mm: Rename the PROT_NONE " Ingo Molnar
2012-10-21 13:22 ` Rik van Riel
2012-10-21 13:29 ` Ingo Molnar
2012-10-21 13:43 ` Ingo Molnar [this message]
2012-10-20 10:15 ` [PATCH 2/2] rename NUMA " Michel Lespinasse
2012-10-21 15:20 ` [tip:numa/core] numa, mm: Rename the PROT_NONE fault handling functions to *_numa() tip-bot for Rik van Riel
2012-10-23 11:00 ` tip-bot for Rik van Riel
2012-10-21 12:43 ` [PATCH 3/2] sched, numa, mm: Implement constant rate working set sampling Ingo Molnar
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