Re: Swap clustering with new VM

[Andrea Arcangeli <andrea@suse.de>]

On Sun, 9 Jul 2000, Marcelo Tosatti wrote:

>AFAIK XFS's pagebuf structure contains a list of contiguous on-disk
>buffers, so the filesystem can do IO on a pagebuf structure avoiding disk
>seek time.
>
>Do you plan to fix the swap clustering problem with a similar idea? 

I don't know pagebuf well enough to understand if it can helps. However
I have a possible solution (not that it looks like to me that there are
many other possible solutions btw ;).

What worries me a bit is that whatever we do to improve swapin seeks it
can always disagree with what the lru says that have to be thrown away.

A dumb way to provide the current swapin-contiguous behaviour is to do a
unmap/swap-around of the pages pointed by the pagetables slots near the
one that we found in the lru.

I guess we could left a sysctl so that we can select between
swapin-optimized or lru-optimized behaviour at runtime to handy bench.

Andrea

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux.eu.org/Linux-MM/