Re: makedumpfile memory usage grows with system memory size

From: Don Zickus <dzickus@redhat.com>
To: Atsushi Kumagai <kumagai-atsushi@mxc.nes.nec.co.jp>
Cc: oomichi@mxs.nes.nec.co.jp, d.hatayama@jp.fujitsu.com,
	kexec@lists.infradead.org, vgoyal@redhat.com
Subject: Re: makedumpfile memory usage grows with system memory size
Date: Tue, 15 May 2012 08:35:38 -0400	[thread overview]
Message-ID: <20120515123538.GR32472@redhat.com> (raw)
In-Reply-To: <20120515145705.d6daeb68.kumagai-atsushi@mxc.nes.nec.co.jp>

On Tue, May 15, 2012 at 02:57:05PM +0900, Atsushi Kumagai wrote:
> Hello Don,
> 
> On Fri, 11 May 2012 09:26:01 -0400
> Don Zickus <dzickus@redhat.com> wrote:
> 
> > > Thank you for your reply, Don, Vivek.
> > > 
> > > As Don said, I tried to change the method to exclude free pages and
> > > planed to resolve the memory consumption issue after it, because
> > > parsing free list repeatedly may cause a performance issue.
> > > 
> > > However, I'm thinking that to fix the size of memory consumption is more
> > > important than to resolve a performance issue for large system.
> > > 
> > > So I'm afraid that I would like to change the plan as:
> > > 
> > >   1. Implement "iterating filtering processing" to fix the size of memory
> > >      consumption. At this stage, makedumpfile will parse free list repeatedly
> > >      even though it may cause a performance issue.
> > >      
> > >   2. Take care of the performance issue after the 1st step.
> > 
> > Hello Atsushi-san,
> > 
> > Hmm.  The problem with the free list is that the addresses are in random
> > order, hence the reason to parse it repeatedly, correct?
> 
> Yes.
> 
> > I figured, now that you have a solution to parse the addresses in a linear
> > way (the changes you made a couple of weeks ago), you would just continue
> > with that.  With that complete, we can look at the performance issues and
> > solve them then.
> > 
> > But it is up to you.  You are willing to do the work, so I will defer to
> > your judgement on how best to proceed. :-)
> 
> What I wanted to tell you was I want to resolve the memory consumption issue
> as soon as possible. In other words, I think the method to exclude free pages
> is not so important.
> I'll continue to work with the method which is easy to implement.

Ok.  I look forward to your results.  Thanks for your effort.

Cheers,
Don

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