On Fri, Dec 04, 2020 at 09:44:43AM +0800, Wei Li wrote: > For the memory hole, sparse memory model that define SPARSEMEM_VMEMMAP > do not free the reserved memory for the page map, decrease the section > size can reduce the waste of reserved memory. > > Signed-off-by: Wei Li <liwei...@huawei.com> > Signed-off-by: Baopeng Feng <fengbaope...@hisilicon.com> > Signed-off-by: Xia Qing <saberlily....@hisilicon.com> > --- > arch/arm64/include/asm/sparsemem.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/include/asm/sparsemem.h > b/arch/arm64/include/asm/sparsemem.h > index 1f43fcc79738..8963bd3def28 100644 > --- a/arch/arm64/include/asm/sparsemem.h > +++ b/arch/arm64/include/asm/sparsemem.h > @@ -7,7 +7,7 @@ > > #ifdef CONFIG_SPARSEMEM > #define MAX_PHYSMEM_BITS CONFIG_ARM64_PA_BITS > -#define SECTION_SIZE_BITS 30 > +#define SECTION_SIZE_BITS 27
We chose '30' to avoid running out of bits in the page flags. What changed? With this patch, I can trigger: ./include/linux/mmzone.h:1170:2: error: Allocator MAX_ORDER exceeds SECTION_SIZE #error Allocator MAX_ORDER exceeds SECTION_SIZE if I bump up NR_CPUS and NODES_SHIFT. Will
