Messages in this thread |  | | Date | Sat, 29 Apr 2017 13:17:26 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCH v2] mm, zone_device: replace {get, put}_zone_device_page() with a single reference |
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On Fri, Apr 28, 2017 at 03:33:07PM -0400, Jerome Glisse wrote: > On Fri, Apr 28, 2017 at 12:22:24PM -0700, Dan Williams wrote: > > Are you sure about needing to hook the 2 -> 1 transition? Could we > > change ZONE_DEVICE pages to not have an elevated reference count when > > they are created so you can keep the HMM references out of the mm hot > > path? > > 100% sure on that :) I need to callback into driver for 2->1 transition > no way around that. If we change ZONE_DEVICE to not have an elevated > reference count that you need to make a lot more change to mm so that > ZONE_DEVICE is never use as fallback for memory allocation. Also need > to make change to be sure that ZONE_DEVICE page never endup in one of > the path that try to put them back on lru. There is a lot of place that > would need to be updated and it would be highly intrusive and add a > lot of special cases to other hot code path.
Could you explain more on where the requirement comes from or point me to where I can read about this.
-- Kirill A. Shutemov
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