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From: Dave Hansen <hansendc@us.ibm.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>,
	containers@lists.osdl.org, menage@google.com,
	linux-kernel@vger.kernel.org, xemul@sw.ru
Subject: Re: [RFC][PATCH 2/7] RSS controller core
Date: Tue, 13 Mar 2007 10:26:33 -0700	[thread overview]
Message-ID: <1173806793.6680.44.camel@localhost.localdomain> (raw)
In-Reply-To: <20070312220439.677b4787.akpm@linux-foundation.org>

On Mon, 2007-03-12 at 22:04 -0800, Andrew Morton wrote:
> So these mmapped pages will contiue to be shared across all guests.  The
> problem boils down to "which guest(s) get charged for each shared page".
> 
> A simple and obvious and easy-to-implement answer is "the guest which paged
> it in".  I think we should firstly explain why that is insufficient.

My first worry was that this approach is unfair to the poor bastard that
happened to get started up first.  If we have a bunch of containerized
web servers, the poor guy who starts Apache first will pay the price for
keeping it in memory for everybody else.

That said, I think this is naturally worked around.  The guy charged
unfairly will get reclaim started on himself sooner.  This will tend to
page out those pages that he was being unfairly charged for.  Hopefully,
they will eventually get pretty randomly (eventually evenly) spread
among all users.  We just might want to make sure that we don't allow
ptes (or other new references) to be re-established to pages like this
when we're trying to reclaim them.  Either that, or force the next
toucher to take ownership of the thing.  But, that kind of arbitrary
ownership transfer can't happen if we have rigidly defined boundaries
for the containers.

The other concern is that the memory load on the system doesn't come
from the first user ("the guy who paged it in").  The long-term load
comes from "the guy who keeps using it."  The best way to exemplify this
is somebody who read()s a page in, followed by another guy mmap()ing the
same page.  The guy who did the read will get charged, and the mmap()er
will get a free ride.  We could probably get an idea when this kind of
stuff is happening by comparing page->count and page->_mapcount, but it
certainly wouldn't be conclusive.  But, does this kind of nonsense even
happen in practice?  

-- Dave


  parent reply	other threads:[~2007-03-13 17:26 UTC|newest]

Thread overview: 129+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-06 14:42 [RFC][PATCH 0/7] Resource controllers based on process containers Pavel Emelianov
2007-03-06 14:49 ` [RFC][PATCH 1/7] Resource counters Pavel Emelianov
2007-03-07  4:03   ` Balbir Singh
2007-03-07  7:19     ` Pavel Emelianov
2007-03-09 16:37       ` Herbert Poetzl
2007-03-11  9:01         ` Pavel Emelianov
2007-03-11 19:00         ` Eric W. Biederman
2007-03-12  1:16           ` Herbert Poetzl
2007-03-13  9:09             ` Eric W. Biederman
2007-03-13  9:27               ` Pavel Emelianov
2007-03-13  9:49               ` [Devel] " Kirill Korotaev
2007-03-13 15:21               ` Herbert Poetzl
2007-03-13 15:41                 ` Pavel Emelianov
2007-03-13 16:07                   ` Srivatsa Vaddagiri
2007-03-14  7:12                     ` Pavel Emelianov
2007-03-15 16:51                       ` Eric W. Biederman
2007-03-13 16:32                   ` Herbert Poetzl
2007-03-06 14:55 ` [RFC][PATCH 2/7] RSS controller core Pavel Emelianov
2007-03-06 22:00   ` Andrew Morton
2007-03-09 16:48     ` Herbert Poetzl
2007-03-11  9:08       ` Pavel Emelianov
2007-03-11 14:32         ` Herbert Poetzl
2007-03-11 15:04           ` Pavel Emelianov
2007-03-12  0:41             ` Herbert Poetzl
2007-03-12  8:31               ` Pavel Emelianov
2007-03-12  9:55       ` Balbir Singh
2007-03-12 23:43         ` Herbert Poetzl
2007-03-13  1:57           ` Balbir Singh
2007-03-13  2:24             ` Srivatsa Vaddagiri
2007-03-13 16:06             ` Herbert Poetzl
2007-03-11 12:26     ` Kirill Korotaev
2007-03-11 12:51       ` Andrew Morton
2007-03-11 15:51         ` Balbir Singh
2007-03-11 19:34         ` Eric W. Biederman
2007-03-12  9:23           ` [Devel] " Kirill Korotaev
2007-03-13  9:26             ` Eric W. Biederman
2007-03-13 15:43               ` Kirill Korotaev
2007-03-12  1:00         ` Herbert Poetzl
2007-03-12  9:02           ` Pavel Emelianov
2007-03-12 21:11             ` Herbert Poetzl
2007-03-13  7:17               ` Pavel Emelianov
2007-03-13 15:05                 ` Herbert Poetzl
2007-03-13 15:32                   ` Pavel Emelianov
2007-03-13 15:10               ` Kirill Korotaev
2007-03-13 15:11                 ` Herbert Poetzl
2007-03-13 15:54                   ` Kirill Korotaev
2007-03-12 18:42           ` Dave Hansen
2007-03-12 22:41             ` Herbert Poetzl
2007-03-12 23:02               ` Dave Hansen
2007-03-18 16:58                 ` Eric W. Biederman
2007-03-13  6:04               ` Andrew Morton
2007-03-13 10:19                 ` [Devel] " Kirill Korotaev
2007-03-13 11:48                   ` Andrew Morton
2007-03-13 14:59                     ` Herbert Poetzl
2007-03-13 17:05                     ` Dave Hansen
2007-03-14 15:38                       ` Mel Gorman
2007-03-14 20:42                         ` Dave Hansen
2007-03-20 18:57                           ` Mel Gorman
2007-03-18 22:44                       ` [Devel] " Paul Menage
2007-03-19 17:41                         ` Eric W. Biederman
2007-03-13 17:26                 ` Dave Hansen [this message]
2007-03-13 19:09                   ` Alan Cox
2007-03-13 20:28                     ` Dave Hansen
2007-03-16  0:55                     ` Eric W. Biederman
2007-03-16 16:31                       ` Dave Hansen
2007-03-16 18:54                         ` Eric W. Biederman
2007-03-16 19:46                           ` Dave Hansen
2007-03-18 17:42                             ` Eric W. Biederman
2007-03-19 15:48                               ` Herbert Poetzl
2007-03-20 16:15                               ` controlling mmap()'d vs read/write() pages Dave Hansen
2007-03-20 21:19                                 ` Eric W. Biederman
2007-03-23  0:51                                   ` Herbert Poetzl
2007-03-23  5:57                                   ` Nick Piggin
2007-03-23 10:12                                     ` Eric W. Biederman
2007-03-23 10:47                                       ` Nick Piggin
2007-03-23 12:21                                         ` Eric W. Biederman
2007-03-28  7:33                                           ` Nick Piggin
2007-03-23 16:41                                       ` Dave Hansen
2007-03-23 18:16                                         ` Herbert Poetzl
2007-03-28  9:18                                           ` Balbir Singh
2007-03-14 16:47                   ` [RFC][PATCH 2/7] RSS controller core Mel Gorman
2007-03-07  5:37   ` Balbir Singh
2007-03-07  7:27     ` Pavel Emelianov
2007-03-06 14:58 ` [RFC][PATCH 3/7] Data structures changes for RSS accounting Pavel Emelianov
2007-03-11 19:13   ` Eric W. Biederman
2007-03-12 16:16     ` Kirill Korotaev
2007-03-12 16:48       ` Dave Hansen
2007-03-12 17:19         ` Pavel Emelianov
2007-03-12 17:27           ` Dave Hansen
2007-03-13  7:10             ` Pavel Emelianov
2007-03-12 17:21         ` Balbir Singh
2007-03-06 15:00 ` [RFC][PATCH 4/7] RSS accounting hooks over the code Pavel Emelianov
2007-03-11 19:14   ` Eric W. Biederman
2007-03-12 16:23     ` Kirill Korotaev
2007-03-12 16:50       ` Dave Hansen
2007-03-12 17:07         ` Kirill Korotaev
2007-03-12 17:33           ` Dave Hansen
2007-03-13  9:43             ` Eric W. Biederman
2007-03-12 23:54         ` Herbert Poetzl
2007-03-13  9:58           ` Eric W. Biederman
2007-03-13 10:25             ` Nick Piggin
2007-03-13 16:01               ` Eric W. Biederman
2007-03-14  3:51                 ` Nick Piggin
2007-03-14  6:42                   ` Balbir Singh
2007-03-14  6:57                     ` Nick Piggin
2007-03-14  7:48                       ` Balbir Singh
2007-03-14 13:25                         ` Vaidyanathan Srinivasan
2007-03-14 13:49                           ` Nick Piggin
2007-03-14 14:43                             ` Vaidyanathan Srinivasan
2007-03-14 16:16                             ` Kirill Korotaev
2007-03-15  5:01                               ` Nick Piggin
2007-03-15  5:44                                 ` Balbir Singh
2007-03-28 20:15               ` Ethan Solomita
2007-03-14 15:37   ` Cedric Le Goater
2007-03-14 15:45     ` Pavel Emelianov
2007-03-06 15:03 ` [RFC][PATCH 5/7] Per-container OOM killer and page reclamation Pavel Emelianov
2007-03-09 21:21   ` Balbir Singh
2007-03-11  8:41     ` Pavel Emelianov
2007-03-06 15:04 ` [RFC][PATCH 6/7] Account for the number of tasks within container Pavel Emelianov
2007-03-07  2:00   ` Paul Menage
2007-03-07  7:13     ` Pavel Emelianov
2007-03-08 13:49       ` Paul Menage
2007-03-11  8:36         ` Pavel Emelianov
2007-03-06 15:07 ` [RFC][PATCH 7/7] Account for the number of files opened " Pavel Emelianov
2007-03-07  2:02 ` [RFC][PATCH 0/7] Resource controllers based on process containers Paul Menage
2007-03-07  7:30   ` Pavel Emelianov
2007-03-07  6:52 ` Balbir Singh
2007-03-07  7:32   ` Pavel Emelianov
2007-03-07  9:43     ` Kirill Korotaev

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