From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jesse Barnes Date: Thu, 08 May 2003 17:20:05 +0000 Subject: Re: [Linux-ia64] Re: [PATCH] head.S fix for unusual load addrs 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 Thu, May 08, 2003 at 10:07:49AM -0700, David Mosberger wrote: > Ah, yes, I had forgotten about -q. It probably would be sufficient. > And the backwards-compatibility it would achieve would definitely be > a plus. I thought so too. > A new concern though: I don't think text-replication will work well > with this scheme. If each replica is linked for a different address, > function pointers become a performance problem: whenever you call > through a function pointer, you'll end up executing on whatever > replica initialized the function pointer. Not good. Right, I thought about that. I don't think we need text replication yet though anyway (at least our platform doesn't). > Unless I'm missing something, kernel relocation is therefore a bit of > a stillborn idea (unless text-replication really isn't all that > important because we all have humongous caches between nodes...). > > If we do have to go the virtual remapping route, my preference would > be to stick the kernel somewhere in region 5 (0xa..). Has anyone > tried that? It should work fine in principle (modules already live in > that space). I guess we can revisit that if we need/want to implement text replication at some point in the future. It might not be that bad though--I don't envision relocating each replica, but rather just seperating the kernel text and data with the right translation registers that point to local text and global data, but I haven't thought about it much (this is what Tony's original patch did, and it seemed to work well). Jesse