On Tue, Jul 16, 2019 at 3:01 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, 18 Jun 2019 21:56:43 +0000 Nadav Amit <namit@xxxxxxxxxx> wrote: > > > > ...and is constant for the life of the device and all subsequent mappings. > > > > > >> Perhaps you want to cache the cachability-mode in vma->vm_page_prot (which I > > >> see being done in quite a few cases), but I don’t know the code well enough > > >> to be certain that every vma should have a single protection and that it > > >> should not change afterwards. > > > > > > No, I'm thinking this would naturally fit as a property hanging off a > > > 'struct dax_device', and then create a version of vmf_insert_mixed() > > > and vmf_insert_pfn_pmd() that bypass track_pfn_insert() to insert that > > > saved value. > > > > Thanks for the detailed explanation. I’ll give it a try (the moment I find > > some free time). I still think that patch 2/3 is beneficial, but based on > > your feedback, patch 3/3 should be dropped. > > It has been a while. What should we do with > > resource-fix-locking-in-find_next_iomem_res.patch This one looks obviously correct to me, you can add: Reviewed-by: Dan Williams <dan.j.williams@xxxxxxxxx> > resource-avoid-unnecessary-lookups-in-find_next_iomem_res.patch This one is a good bug report that we need to go fix pgprot lookups for dax, but I don't think we need to increase the trickiness of the core resource lookup code in the meantime.