On Sat, Sep 12, 2020 at 3:45 AM Mike Rapoport <[email protected]> wrote: > > Hello Atish, > > On Fri, Sep 11, 2020 at 05:23:41PM -0700, Atish Patra wrote: > > Currently, any usable memory area beyond page_offset is removed by adding > > the > > memory sizes from each memblock. That may not work for sparse memory > > as memory regions can be very far apart resulting incorrect removal of some > > usable memory. > > If I understand correctly, the memory with physical addresses larger > than (-PAGE_OFFSET) cannot be used. Since it was aready > memblock_add()'ed during device tree parsing, you need to remove it from > memblock. >
IIRC, the original intention was to fix MAXPHYSMEM_2GB option for RV64 for the medlow model. That's why the patch removed any memory beyond -PAGE_OFFSET. > For that you can use memblock_enforce_memory_limit(-PAGE_OFFSET). > Thanks. I think we can just call memblock_enforce_memory_limit without tracking the total memory size and whether maximum memory described in DT is greater than -PAGE_OFFSET. @Anup Patel Was there any other reason for this change originally? > > Just use the start of the first memory block and the end of the last memory > > block to compute the size of the total memory that can be used. > > > > Signed-off-by: Atish Patra <[email protected]> > > --- > > arch/riscv/mm/init.c | 6 ++---- > > 1 file changed, 2 insertions(+), 4 deletions(-) > > > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > > index 787c75f751a5..188281fc2816 100644 > > --- a/arch/riscv/mm/init.c > > +++ b/arch/riscv/mm/init.c > > @@ -147,7 +147,6 @@ void __init setup_bootmem(void) > > { > > struct memblock_region *reg; > > phys_addr_t mem_size = 0; > > - phys_addr_t total_mem = 0; > > phys_addr_t mem_start, end = 0; > > phys_addr_t vmlinux_end = __pa_symbol(&_end); > > phys_addr_t vmlinux_start = __pa_symbol(&_start); > > @@ -155,18 +154,17 @@ void __init setup_bootmem(void) > > /* Find the memory region containing the kernel */ > > for_each_memblock(memory, reg) { > > end = reg->base + reg->size; > > - if (!total_mem) > > + if (!mem_start) > > mem_start = reg->base; > > if (reg->base <= vmlinux_start && vmlinux_end <= end) > > BUG_ON(reg->size == 0); > > - total_mem = total_mem + reg->size; > > } > > > > /* > > * Remove memblock from the end of usable area to the > > * end of region > > */ > > - mem_size = min(total_mem, (phys_addr_t)-PAGE_OFFSET); > > + mem_size = min(end - mem_start, (phys_addr_t)-PAGE_OFFSET); > > if (mem_start + mem_size < end) > > memblock_remove(mem_start + mem_size, > > end - mem_start - mem_size); > > -- > > 2.24.0 > > > > -- > Sincerely yours, > Mike. > > _______________________________________________ > linux-riscv mailing list > [email protected] > http://lists.infradead.org/mailman/listinfo/linux-riscv -- Regards, Atish
