Re: Fairness in love and swapping

[Rik van Riel <H.H.vanRiel@fys.ruu.nl>]

On Fri, 27 Feb 1998, Stephen C. Tweedie wrote:

> > AFAIK, mapped images aren't part of a proces' RSS, but
> > are page-cached (page->inode type of RSS). And swapping
> > of those vma's _is_ done in shrink_mmap() in filemap.c.
> 
> No, absolutely not.  These pages are certainly present in the page
[snip]
> > But if I've overlooked something, I'd really like to hear about
> > it... A bit of a clue never hurts when coding up new patches :-)
> 
> You're welcome. :)

Nevertheless, the system seems to run smoother when the
page-cache pages aren't thrown away immediately, but aged
as normal pages are. Read-ahead pages _are_ sometimes
freed before they're actually used, so in this case the
system _will_ have to read them again. But maybe a 'true'
LRU implementation for the 'hardy-referenced' pages might
be better (with a sysctl tunable timing thing).

start:
	page->age |= (1 << lru_age_factor)
referenced:
	page->age >>= 1
	page->age |= (1 << lru_age_factor)
not-referenced:
	page->age >>=1

grtz,

Rik.
+-----------------------------+------------------------------+
| For Linux mm-patches, go to | "I'm busy managing memory.." |
| my homepage (via LinuxHQ).  | H.H.vanRiel@fys.ruu.nl       |
| ...submissions welcome...   | http://www.fys.ruu.nl/~riel/ |
+-----------------------------+------------------------------+