From mboxrd@z Thu Jan  1 00:00:00 1970
To: 9fans@cse.psu.edu
From: "Douglas A. Gwyn" <DAGwyn@null.net>
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References: <20040228105025.1a94f714.martin@parvat.com>, <000d01c3fddf$72cc45b0$2bdcfea9@blue>
Subject: Re: [9fans] Threads: Sewing badges of honor onto a Kernel
Date: Mon,  1 Mar 2004 10:35:19 +0000
Topicbox-Message-UUID: 06b3c168-eacd-11e9-9e20-41e7f4b1d025

Nigel Roles wrote:
> The performance argument may well still be regarded by Linus as
> stronger, but there are other differences. One is that the stack
> used by the clone, being allocated on the heap, is fixed in size,
> and unprotected from overflow.

That would be a serious flaw on a system with a small address space.
It's problematic anyway in its inefficient use of PTEs for the
process, since far more table entries are needed (extra stack
for each thread).

However, overflow detection can in principle be achieved by
mapping all pages of each thread's private stack region except
for the last page, which allows the MMU to flag any overflow.