[gclist] Re: gclist-digest V3 #106

Nick Barnes Nick.Barnes@pobox.com
Wed, 20 Sep 2000 15:11:50 +0100

At 2000-09-20 13:21:37+0000, David Chase writes:
> At 01:30 PM 9/20/00 +0100, Nick Barnes wrote:
> >For such memory managers, a source of pages with "don't care" contents
> >may be a worthwhile optimisation.
> This assumes that you can get such pages.  Unless they are your
> own old pages, "don't care" pages constitute a security hole.
> I know, not *usually* a GC consideration, but there's little
> point wishing for something nobody is willing to give you.

Yes, I mentioned this point in my earlier message on the subject.  The
pages in question would have to be old pages from the same process.

> As for how the pages get zero-filled, on my box, I find that
> the second processor often gets that job.  It's the easiest and
> sleaziest way I know of to make use of a multiprocessor in a
> garbage collector.


My suggestion simply amounts to this: We have /dev/zero, which is very
useful to us but has a property (zero filling) which costs us
something and which we do not need.  A device like /dev/zero but
without this property would be even better.

Nick B

FreeBSD 2.2.8-RELEASE: up 24 days, 18:21
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