On Wed, Dec 2, 2015 at 4:21 PM, Toshi Kani <toshi.kani@xxxxxxx> wrote: > 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. Ok, I need to switch over from my memmap=ss!nn config. We just need to pad the info block reservation to 2M. As for the MAP_POPULATE hang, I'll take a look. Right now I'm in the process of rebasing the whole set on top of -mm which has a pending THP re-works from Kirill. -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
