On Wed, 2008-02-27 at 14:37 +0100, Rob van der Heij wrote: > Oh, and I doubt your patch does the trick. The ESSA will program check > when not there. I don't think fault.c will like that.
The EX_TABLE entry will take care of the fault. As far as I can tell Heikos patch is fine. > PS I did read that Brian Wade's experiments were done with cmma=on and > use the CP settings to enable / disable the feature. When my > assumptions about the implementation are correct, then that was indeed > the right way to do it. But it does not reveal what will happen to > customers who end up with a mix of penguins. This would be an interesting experiment. The difference between cmma=on and cmma=off for a page cache page that has been paged-out by z/VM is not big. If a guest accesses such a page with cmma=off the z/VM system will initiate an i/o to get the page and deliver a pfault interrupt to the guest so that the guest can schedule another process. If a guest uses cmma=on it will get a discard fault on access of a paged-out page. In this case it is Linux that initiates the i/o. The process will have to wait for page and another process is scheduled. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
