From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Fri, 24 Aug 2001 18:19:23 +0000 Subject: Re: [Linux-ia64] Simple question about pointers address space. Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Fri, 24 Aug 2001 14:10:23 -0400, "Dominic Duchemin" said: Dominic> I would simply like to know if the possible address Dominic> space (2^64) by a pointer is fulllly or partially used in Dominic> the context of a process in the linux ia64 kernel. All 64 bits are used (there are no ignored bits), though depending on the OS and CPU, some of the address space may be inaccessible (will trigger a fault if accessed). Dominic> In the partial case, which part of the 2^64 is used. Dominic> The anser to this question is important for Dominic> me. Because what i try to do is to mix a reference Dominic> counter&pointer for atomic operation on pointers. So if Dominic> there is unused bits in the 64 bits pointer, I'll use them. The only bits you might be able use for this purpose are low order bits that are zero due to alignment constraints. E.g., if your objects are all 16-byte aligned, you could use the least-significant 4 bits. --david