Messages in this thread | | | Date | Sat, 12 Sep 2020 13:45:02 +0300 | From | Mike Rapoport <> | Subject | Re: [PATCH] RISC-V: Consider sparse memory while removing unusable memory |
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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.
For that you can use memblock_enforce_memory_limit(-PAGE_OFFSET).
> 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 <atish.patra@wdc.com> > --- > 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.
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