On Tue, 11 May 2021 at 12:06, Mike Rapoport <rppt@xxxxxxxxxx> wrote: > > From: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > The arm64's version of pfn_valid() differs from the generic because of two > reasons: > > * Parts of the memory map are freed during boot. This makes it necessary to > verify that there is actual physical memory that corresponds to a pfn > which is done by querying memblock. > > * There are NOMAP memory regions. These regions are not mapped in the > linear map and until the previous commit the struct pages representing > these areas had default values. > > As the consequence of absence of the special treatment of NOMAP regions in > the memory map it was necessary to use memblock_is_map_memory() in > pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that > generic mm functionality would not treat a NOMAP page as a normal page. > > Since the NOMAP regions are now marked as PageReserved(), pfn walkers and > the rest of core mm will treat them as unusable memory and thus > pfn_valid_within() is no longer required at all and can be disabled by > removing CONFIG_HOLES_IN_ZONE on arm64. > > pfn_valid() can be slightly simplified by replacing > memblock_is_map_memory() with memblock_is_memory(). > > Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> Acked-by: Ard Biesheuvel <ardb@xxxxxxxxxx> ... and many thanks for cleaning this up. > --- > arch/arm64/Kconfig | 3 --- > arch/arm64/mm/init.c | 2 +- > 2 files changed, 1 insertion(+), 4 deletions(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 9f1d8566bbf9..d7dc8698cf8e 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -1052,9 +1052,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK > def_bool y > depends on NUMA > > -config HOLES_IN_ZONE > - def_bool y > - > source "kernel/Kconfig.hz" > > config ARCH_SPARSEMEM_ENABLE > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 798f74f501d5..fb07218da2c0 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -251,7 +251,7 @@ int pfn_valid(unsigned long pfn) > if (!early_section(ms)) > return pfn_section_valid(ms, pfn); > > - return memblock_is_map_memory(addr); > + return memblock_is_memory(addr); > } > EXPORT_SYMBOL(pfn_valid); > > -- > 2.28.0 >
