Re: [2.4.17/18pre] VM and swap - it's really unusable

Bill Davidsen
2002-01-14T00:55:38Z

On Tue, 8 Jan 2002, Andrea Arcangeli wrote:

> Note that some of them are bugfixes, without them an luser can hang the
> machine for several seconds on any box with some giga of ram by simple
> reading and writing into a large enough buffer. I think we never had
> time to care merging those bits into mainline yet and this is probably
> the main reason they're not integrated but it's something that should be
> in mainline IMHO.

Or just doing a large write while doing lots of reads... my personal
nemesis is "mkisofs" for backups, which reads lots of small files and
builds a CD image, which suddenly gets discovered by the kernel and
written, seemingly in a monolythic chunk. I MAY be able to improve this
with tuning the bdflush parameters, and I tried some tentative patches
which didn't make a huge gain.

I don't know if the solution lies in forcing write to start when a certain
size of buffers are queued regardless of percentages, or in better
scheduling of reads ahead of writes, or whatever.

--
bill davidsen <davidsen@tmr.com>
CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.