lkml.org 
[lkml]   [2010]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cache control
On Thu, 10 Jun 2010 17:07:32 -0700
Dave Hansen <dave@linux.vnet.ibm.com> wrote:

> On Thu, 2010-06-10 at 19:55 +0530, Balbir Singh wrote:
> > > I'm not sure victimizing unmapped cache pages is a good idea.
> > > Shouldn't page selection use the LRU for recency information instead
> > > of the cost of guest reclaim? Dropping a frequently used unmapped
> > > cache page can be more expensive than dropping an unused text page
> > > that was loaded as part of some executable's initialization and
> > > forgotten.
> >
> > We victimize the unmapped cache only if it is unused (in LRU order).
> > We don't force the issue too much. We also have free slab cache to go
> > after.
>
> Just to be clear, let's say we have a mapped page (say of /sbin/init)
> that's been unreferenced since _just_ after the system booted. We also
> have an unmapped page cache page of a file often used at runtime, say
> one from /etc/resolv.conf or /etc/passwd.
>

Hmm. I'm not fan of estimating working set size by calculation
based on some numbers without considering history or feedback.

Can't we use some kind of feedback algorithm as hi-low-watermark, random walk
or GA (or somehing more smart) to detect the size ?

Thanks,
-Kame






\
 
 \ /
  Last update: 2010-06-11 04:01    [W:0.197 / U:0.604 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site