On Wed, 2015-12-02 at 10:43 -0700, Toshi Kani wrote: > On Tue, 2015-12-01 at 19:45 -0800, Dan Williams wrote: > > On Tue, Dec 1, 2015 at 6:19 PM, Toshi Kani <toshi.kani@xxxxxxx> wrote: > > > On Mon, 2015-11-30 at 14:08 -0800, Dan Williams wrote: : > > > > > > > > Hey Toshi, > > > > > > > > I ended up fixing this differently with follow_pmd_devmap() introduced > > > > in this series: > > > > > > > > https://lists.01.org/pipermail/linux-nvdimm/2015-November/003033.html > > > > > > > > Does the latest libnvdimm-pending branch [1] pass your test case? > > > > > > Hi Dan, > > > > > > I ran several test cases, and they all hit the case "pfn not in memmap" in > > > __dax_pmd_fault() during mmap(MAP_POPULATE). Looking at the dax.pfn, > > > PFN_DEV is set but PFN_MAP is not. I have not looked into why, but I > > > thought I let you know first. I've also seen the test thread got hung up > > > at the end sometime. > > > > That PFN_MAP flag will not be set by default for NFIT-defined > > persistent memory. See pmem_should_map_pages() for pmem namespaces > > that will have it set by default, currently only e820 type-12 memory > > ranges. > > > > NFIT-defined persistent memory can have a memmap array dynamically > > allocated by setting up a pfn device (similar to setting up a btt). > > We don't map it by default because the NFIT may describe hundreds of > > gigabytes of persistent and the overhead of the memmap may be too > > large to locate the memmap in ram. > > Oh, I see. I will setup the memmap array and run the tests again. I setup a pfn device, and ran a few test cases again. Yes, it solved the PFN_MAP issue. However, I am no longer able to allocate FS blocks aligned by 2MB, so PMD faults fall back to PTE. They are off by 2 pages, which I suspect due to the pfn metadata. If I pass a 2MB-aligned+2pages virtual address to mmap(MAP_POPULATE), the mmap() call gets hung up. Thanks, -Toshi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>