Re: Linux 2.4.18pre3-ac1

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Mon Jan 21 2002 - 00:30:26 EST


Daniel Phillips writes:
> The way I see it, the purpose of lazy page table instantiation is to
> overcome objections to the reverse pte mapping vm technique that
> have been expressed in the past, namely the slowdown in dup_mmap
> inside fork. I.e., if rmap slows down fork then Linus and Davem are
> going to veto it, as they've done in the past, because they feel
> that the as-yet-unproven advantages of physically-based vm scanning
> doesn't outweigh the easily measurable fork overhead. Personally, I
> think that's debatable, but by eliminating the overhead we eliminate
> the objection, and as far as I know, it's the only serious
> objection.

Will lazy page table instantiation speed up fork(2) without rmap?
If so, then you've got a problem, because rmap will still be slower
than non-rmap. Linus will happily grab any speedup and make that the
new baseline against which new schemes are compared :-)

                                Regards,

                                        Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Wed Jan 23 2002 - 21:00:42 EST