On Thu, Jun 20, 2019 at 5:31 AM Aneesh Kumar K.V aneesh.kumar@linux.ibm.com wrote:
Dan Williams dan.j.williams@intel.com writes:
Changes since v9 [1]:
Fix multiple issues related to the fact that pfn_valid() has traditionally returned true for any pfn in an 'early' (onlined at boot) section regardless of whether that pfn represented 'System RAM'. Teach pfn_valid() to maintain its traditional behavior in the presence of subsections. Specifically, subsection precision for pfn_valid() is only considered for non-early / hot-plugged sections. (Qian)
Related to the first item introduce a SECTION_IS_EARLY (->section_mem_map flag) to remove the existing hacks for determining an early section by looking at whether the usemap was allocated from the slab.
Kill off the EEXIST hackery in __add_pages(). It breaks (arch_add_memory() false-positive) the detection of subsection collisions reported by section_activate(). It is also obviated by David's recent reworks to move the 'System RAM' request_region() earlier in the add_memory() sequence().
Switch to an arch-independent / static subsection-size of 2MB. Otherwise, a per-arch subsection-size is a roadblock on the path to persistent memory namespace compatibility across archs. (Jeff)
Update the changelog for "libnvdimm/pfn: Fix fsdax-mode namespace info-block zero-fields" to clarify that the "Cc: stable" is only there as safety measure for a distro that decides to backport "libnvdimm/pfn: Stop padding pmem namespaces to section alignment", otherwise there is no known bug exposure in older kernels. (Andrew)
Drop some redundant subsection checks (Oscar)
Collect some reviewed-bys
You can add Tested-by: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com for ppc64.
Thank you!
BTW even after this series we have the kernel crash mentioned in the below email on reconfigure.
https://lore.kernel.org/linux-mm/20190514025354.9108-1-aneesh.kumar@linux.ib...
I guess we need to conclude how the reserve space struct page should be initialized ?
Yes, that issue is independent of the subsection changes. I'll take a closer look.