From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jes Sorensen Date: Tue, 24 Jan 2006 09:14:28 +0000 Subject: Re: [PATCH] SN2 user-MMIO CPU migration Message-Id: <43D5EFF4.9090206@sgi.com> List-Id: References: <20060118163305.Y42462@chenjesu.americas.sgi.com> In-Reply-To: <20060118163305.Y42462@chenjesu.americas.sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Luck, Tony wrote: > Thinking about this a bit more, wouldn't it be better to do this > work in the rebalance code that is making the decision to move > the process. The earlier argument that this would sometimes > waste time because the process might not actually move doesn't > sound so strong ... we context switch frequently, we move processes > rarely. Doing some work that may be wasted in the rare path sounds > better than always doing work in the common path. Alternatively one could make platform_switch_from() a wrapper around a function pointer that is only set when in use. Then it would be a load and a compare and the rest will be predicated away on non SN hardware in the generic kernel. Cheers, Jes