Hello Nikhil, On Wed, Sep 28, 2016 at 2:41 PM, Nikhil Utane <nikhil.subscribed@xxxxxxxxx> wrote: > Arun, > > What seems to have done the trick is calling memblock_remove() followed by a > call to request_mem_region(). This creates a hole which can be confirmed in > the output of /proc/iomem. > > Do you see any issue with this approach? I really don't know how it works for you. Marking address of a page as iomem. How buddy allocator ignores this page? request_mem_region() is a way of managing IO resource memory, to avoid two drivers using same IO memory. It has not relation with buddy allocator. Can you post code snippet? Regards, Arun > > -Thanks > Nikhil > > On Tue, Sep 27, 2016 at 4:14 PM, Arun Sudhilal <getarunks@xxxxxxxxx> wrote: >> >> Hello Nikhil, >> >> On Fri, Sep 9, 2016 at 7:01 AM, Nikhil Utane >> <nikhil.subscribed@xxxxxxxxx> wrote: >> > I want to reserve a physical memory page with a fixed PFN. I do not want >> > this page to be used by anyone else. I am calling memblock_reserve() to >> > supposedly reserve the page. I am writing some content into this page. >> > What >> > I see is that during some runs the content of this page is modified >> > (either >> > fully or sometimes partially). In few runs, I see it as intact. Is it >> > expected that even after calling memblock_reserve() the kernel can >> > allocate >> > this physical page for any other purpose? How is memblock_remove() >> > different >> > from memblock_reserve? I tried reading up but didn't see any useful >> > information. What I understood is memblock_remove will completely remove >> > from kernel's allocation mechanism. Should I then be using remove >> > instead of >> > reserve? >> >> when a DT entry is added to #reserved-memory node, what >> drivers/of/fdt.c does is to call memblock_remove() and >> memblock_reserve(). >> This happens after the memblock driver is initialized but before buddy >> allocator up. Did you try this approach? This should work for you. >> >> Only option once the kernel boot is complete is to try out the >> technique what mm/memory_hotplug.c does while offline memory. >> isolate_page_range and then migrate. >> >> Regards, >> Arun >> >> >> > >> > -Thanks >> > Nikhil >> > >> > _______________________________________________ >> > Kernelnewbies mailing list >> > Kernelnewbies@xxxxxxxxxxxxxxxxx >> > https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> > > > _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
