Re: Maybe a VM bug in 2.4.18-18 from RH 8.0?

From: Andrea Arcangeli (andrea@suse.de)
Date: Fri Dec 06 2002 - 17:34:59 EST


On Fri, Dec 06, 2002 at 07:12:38AM -0800, William Lee Irwin III wrote:
> split just to get a bloated mem_map to fit. Many of the smaller apps,
> e.g. /bin/sh etc. are indifferent to the ABI violation.

the problem of the split is that it would reduce the address space
available to userspace that is quite critical on big machines (one of
the big advantages of 64bit that can't be fixed on 32bit) but I wouldn't
classify it as an ABI violation, infact the little I can remember about
the 2.0 kernels [I almost never read that code] is that it had shared
address space and tlb flush while entering/exiting kernel, so I can bet
the user stack in 2.0 was put at 4G, not at 3G. 2.2 had to put it at 3G
because then the address space was shared with the obvious performance
advantages, so while I didn't read any ABI, I deduce you can't say the
ABI got broken if the stack is put at 2G or 1G or 3.5G or 4G again with
x86-64 (of course x86-64 can give the full 4G to userspace because the
kernel runs in the negative part of the [64bit] address space, as 2.0
could too).

Andrea
-
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 : Sat Dec 07 2002 - 22:00:28 EST