On Wed, Oct 25, 2023 at 05:52:58PM +0900, Hyesoo Yu wrote: > If we only avoid using ALLOC_CMA for __GFP_TAGGED, would we still be able to use > the next iteration even if the hardware does not support "tag of tag" ? It depends on how the next iteration looks like. The plan was not to support this so that we avoid another complication where a non-tagged page is mprotect'ed to become tagged and it would need to be migrated out of the CMA range. Not sure how much code it would save. > I am not sure every vendor will support tag of tag, since there is no information > related to that feature, like in the Google spec document. If you are aware of any vendors not supporting this, please direct them to the Arm support team, it would be very useful information for us. Thanks. -- Catalin