linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Daniel Phillips <phillips@arcor.de>
To: "Martin J. Bligh" <mbligh@aracnet.com>,
	Dave McCracken <dmccr@us.ibm.com>,
	"Gerold J. Wucherpfennig" <gjwucherpfennig@gmx.net>,
	linux-kernel@vger.kernel.org
Subject: Re: Page table sharing
Date: Tue, 1 Oct 2002 18:28:52 +0200	[thread overview]
Message-ID: <E17wPtF-0005uu-00@starship> (raw)
In-Reply-To: <851859439.1033463169@[10.10.2.3]>

On Tuesday 01 October 2002 18:06, Martin J. Bligh wrote:
> > I'm not sure how relevant page table sharing has to the halloween 
> > deadline since it's not a feature per se, just an optimization.   
> > It has more to do with getting numa ia32 boxes to survive, so it's 
> > an ideal out-of-tree patch.
> 
> Any large 32 bit box with significant numbers of processes will need 
> it to cope with the bloat that rmap introduced - this has nothing to
> do with NUMA (some apps may be saved by large pages, some not). 
> Avoiding hangs from ZONE_NORMAL oom is not an "optimisation", and I 
> doubt optimisations involving major VM changes would be very welcome
> after the freeze. This is something we need to get working ASAP ...

Any reason why page table swapping wouldn't deliver just as much bang
for the buck?  Same argument re VM changes.

Anyway, I don't necessarily buy the VM change argument.  I've already
established that turning sharing off either at compile time or run
time is trivial, so there is no element of risk.  I'd suggest: take
a deep breath, relax, go slow and get it right.

What we should be coding right now is the patch Linus already asked
for, to recover page table pages as soon as possible instead of in
clear_page_tables.  With that in place the locking for shared page
tables gets a lot nicer, as Linus showed.

-- 
Daniel

      reply	other threads:[~2002-10-01 16:35 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-09-25 18:12 Gerold J. Wucherpfennig
2002-09-25 18:40 ` Dave McCracken
2002-09-26 18:20   ` Gerold J. Wucherpfennig
2002-10-01 13:08   ` Daniel Phillips
2002-10-01 16:06     ` Martin J. Bligh
2002-10-01 16:28       ` Daniel Phillips [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=E17wPtF-0005uu-00@starship \
    --to=phillips@arcor.de \
    --cc=dmccr@us.ibm.com \
    --cc=gjwucherpfennig@gmx.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mbligh@aracnet.com \
    --subject='Re: Page table sharing' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).