On Wed, Feb 19, 2020 at 08:37:25AM -0800, Dan Williams wrote: > On Wed, Feb 19, 2020 at 12:57 AM Mike Rapoport <rppt@xxxxxxxxxxxxx> wrote: > > > > On Tue, Feb 18, 2020 at 07:25:15PM -0800, Dan Williams wrote: > > > On Tue, Feb 18, 2020 at 7:05 PM Baoquan He <bhe@xxxxxxxxxx> wrote: > > > > > > > > From: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx> > > > > > > > > When we use SPARSEMEM instead of SPARSEMEM_VMEMMAP, pfn_to_page() > > > > doesn't work before sparse_init_one_section() is called. This leads to a > > > > crash when hotplug memory: > > > > > > I'd also add: > > > > > > "On x86 the impact is limited to x86_32 builds, or x86_64 > > > configurations that override the default setting for > > > SPARSEMEM_VMEMMAP". > > > > Do we also want to check how it affects, say, arm64, ia64 and ppc? ;-) > > Sure, I just did not take the time to look up their respective default > stances on SPARSEMEM_VMEMMAP. For a distro looking to backport this > commit I think it's helpful for them to understand if they are exposed > or not. Looks like only i386_defconfig does not enable SPARSEMEM_VMEMMAP. All the rest may have it disabled only with manual override. -- Sincerely yours, Mike.
