Subject: [PATCHv3 2/2] arm: Get rid of meminfo

From: [email-masked] (Grygorii Strashko)
Date: Wed, 12 Feb 2014 17:09:05 +0200

Hi Laura,

On 02/11/2014 11:14 PM, Laura Abbott wrote:
> memblock is now fully integrated into the kernel and is the prefered
> method for tracking memory. Rather than reinvent the wheel with
> meminfo, migrate to using memblock directly instead of meminfo as
> an intermediate.
> 
> Acked-by: Jason Cooper <[email-masked]>
> Acked-by: Catalin Marinas <[email-masked]>
> Acked-by: Santosh Shilimkar <[email-masked]>
> Tested-by: Leif Lindholm <[email-masked]>
> Signed-off-by: Laura Abbott <[email-masked]>
> ---
>   arch/arm/include/asm/mach/arch.h         |    4 +-
>   arch/arm/include/asm/memblock.h          |    3 +-
>   arch/arm/include/asm/setup.h             |   23 ------
>   arch/arm/kernel/atags_parse.c            |    5 +-
>   arch/arm/kernel/devtree.c                |    5 --
>   arch/arm/kernel/setup.c                  |   30 ++------
>   arch/arm/mach-clps711x/board-clep7312.c  |    7 +-
>   arch/arm/mach-clps711x/board-edb7211.c   |   10 +--
>   arch/arm/mach-clps711x/board-p720t.c     |    2 +-
>   arch/arm/mach-footbridge/cats-hw.c       |    2 +-
>   arch/arm/mach-footbridge/netwinder-hw.c  |    2 +-
>   arch/arm/mach-msm/board-halibut.c        |    6 --
>   arch/arm/mach-msm/board-mahimahi.c       |   13 +---
>   arch/arm/mach-msm/board-msm7x30.c        |    3 +-
>   arch/arm/mach-msm/board-sapphire.c       |   13 ++--
>   arch/arm/mach-msm/board-trout.c          |    8 +--
>   arch/arm/mach-orion5x/common.c           |    3 +-
>   arch/arm/mach-orion5x/common.h           |    3 +-
>   arch/arm/mach-pxa/cm-x300.c              |    3 +-
>   arch/arm/mach-pxa/corgi.c                |   10 +--
>   arch/arm/mach-pxa/eseries.c              |    9 +--
>   arch/arm/mach-pxa/poodle.c               |    8 +--
>   arch/arm/mach-pxa/spitz.c                |    8 +--
>   arch/arm/mach-pxa/tosa.c                 |    8 +--
>   arch/arm/mach-realview/core.c            |   11 +--
>   arch/arm/mach-realview/core.h            |    3 +-
>   arch/arm/mach-realview/realview_pb1176.c |    8 +--
>   arch/arm/mach-realview/realview_pbx.c    |   17 ++---
>   arch/arm/mach-s3c24xx/mach-smdk2413.c    |    8 +--
>   arch/arm/mach-s3c24xx/mach-vstms.c       |    8 +--
>   arch/arm/mach-sa1100/assabet.c           |    2 +-
>   arch/arm/mm/init.c                       |   67 +++++++-----------
>   arch/arm/mm/mmu.c                        |  115 +++++++++---------------------

The arch/arm/mm/nommu.c has to be updated too :)

[...]

I've tested your change on keystone (with some additional printouts in sanity_check_meminfo())
and got following results:

- without your change + HIGHMEM=ON
[    0.000000] ==== memblock_limit0x00000000af800000, arm_lowmem_limit0x00000000af800000 high_memoryef800000 vmalloc_limit0x00000000af800000

 - without your change + HIGHMEM=OFF
[    0.000000] Truncating RAM at 80000000-bfffffff to -af7fffff (vmalloc region overlap).
[    0.000000] ==== memblock_limit0x00000000af800000, arm_lowmem_limit0x00000000af800000 high_memoryef800000 vmalloc_limit0x00000000af800000

- with your change + HIGHMEM=ON
[    0.000000] ==== memblock_limit0x00000000af800000, arm_lowmem_limit0x00000000af800000 high_memoryef800000 vmalloc_limit0x00000000af800000

- with your change + HIGHMEM=OFF
[    0.000000] Truncating RAM at 0x0000000080000000-0x00000000c0000000 to -0x0000000010800000
                                                                          ^printout changed
[    0.000000] ==== memblock_limit0x00000000af800000, arm_lowmem_limit0x00000000af800000 high_memoryef800000 vmalloc_limit0x00000000af800000

Keystone mem defined as: from at 0x80000000 size at 0x40000000 (LPAE=OFF)

As result, i have few comments regarding sanity_check_meminfo() changes as I think there are
some issues &side effects changes at least in printouts - see below.

>   	memblock_reserve(__pa(_sdata), _end - _sdata);
> @@ -413,54 +397,53 @@ free_memmap(unsigned long start_pfn, unsigned long end_pfn)
>   /*
>    * The mem_map array can get very big.  Free the unused area of the memory map.
>    */
> -static void __init free_unused_memmap(struct meminfo *mi)
> +static void __init free_unused_memmap(void)
>   {
> -	unsigned long bank_start, prev_bank_end = 0;
> -	unsigned int i;
> +	unsigned long start, prev_end = 0;
> +	struct memblock_region *reg;
>   
>   	/*
>   	 * This relies on each bank being in address order.
>   	 * The banks are sorted previously in bootmem_init().
>   	 */
> -	for_each_bank(i, mi) {
> -		struct membank *bank = &mi->bank[i];
> -
> -		bank_start = bank_pfn_start(bank);
> +	for_each_memblock(memory, reg) {
> +		start = __phys_to_pfn(reg->base);

memblock_region_memory_base_pfn() can be used here.

>   
>   #ifdef CONFIG_SPARSEMEM
>   		/*
>   		 * Take care not to free memmap entries that don't exist
>   		 * due to SPARSEMEM sections which aren't present.
>   		 */
> -		bank_start = min(bank_start,
> -				 ALIGN(prev_bank_end, PAGES_PER_SECTION));
> +		start = min(start,
> +				 ALIGN(prev_end, PAGES_PER_SECTION));
>   #else
>   		/*
>   		 * Align down here since the VM subsystem insists that the
>   		 * memmap entries are valid from the bank start aligned to
>   		 * MAX_ORDER_NR_PAGES.
>   		 */
> -		bank_start = round_down(bank_start, MAX_ORDER_NR_PAGES);
> +		start = round_down(start, MAX_ORDER_NR_PAGES);
>   #endif
>   		/*
>   		 * If we had a previous bank, and there is a space
>   		 * between the current bank and the previous, free it.
>   		 */
> -		if (prev_bank_end && prev_bank_end < bank_start)
> -			free_memmap(prev_bank_end, bank_start);
> +		if (prev_end && prev_end < start)
> +			free_memmap(prev_end, start);
>   
>   		/*
>   		 * Align up here since the VM subsystem insists that the
>   		 * memmap entries are valid from the bank end aligned to
>   		 * MAX_ORDER_NR_PAGES.
>   		 */
> -		prev_bank_end = ALIGN(bank_pfn_end(bank), MAX_ORDER_NR_PAGES);
> +		prev_end = ALIGN(start + __phys_to_pfn(reg->size),

I think, start + __phys_to_pfn(reg->size) can be replaced by
memblock_region_memory_end_pfn().

> +				 MAX_ORDER_NR_PAGES);
>   	}
>   
>   #ifdef CONFIG_SPARSEMEM
> -	if (!IS_ALIGNED(prev_bank_end, PAGES_PER_SECTION))
> -		free_memmap(prev_bank_end,
> -			    ALIGN(prev_bank_end, PAGES_PER_SECTION));
> +	if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
> +		free_memmap(prev_end,
> +			    ALIGN(prev_end, PAGES_PER_SECTION));
>   #endif
>   }
>   
> @@ -536,7 +519,7 @@ void __init mem_init(void)
>   	set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
>   
>   	/* this will put all unused low memory onto the freelists */
> -	free_unused_memmap(&meminfo);
> +	free_unused_memmap();
>   	free_all_bootmem();
>   
>   #ifdef CONFIG_SA1111
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 4f08c13..23433ef 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -1046,74 +1046,44 @@ phys_addr_t arm_lowmem_limit __initdata = 0;
>   void __init sanity_check_meminfo(void)
>   {
>   	phys_addr_t memblock_limit = 0;
> -	int i, j, highmem = 0;
> +	int highmem = 0;
>   	phys_addr_t vmalloc_limit = __pa(vmalloc_min - 1) + 1;
> +	struct memblock_region *reg;
>   
> -	for (i = 0, j = 0; i < meminfo.nr_banks; i++) {
> -		struct membank *bank = &meminfo.bank[j];
> -		phys_addr_t size_limit;
> -
> -		*bank = meminfo.bank[i];
> -		size_limit = bank->size;
> +	for_each_memblock(memory, reg) {
> +		phys_addr_t block_start = reg->base;
> +		phys_addr_t block_end = reg->base + reg->size;
> +		phys_addr_t size_limit = reg->size;
>   
> -		if (bank->start >= vmalloc_limit)
> +		if (reg->base >= vmalloc_limit)
>   			highmem = 1;
>   		else
> -			size_limit = vmalloc_limit - bank->start;
> +			size_limit = vmalloc_limit - reg->base;
>   
> -		bank->highmem = highmem;
>   
> -#ifdef CONFIG_HIGHMEM
> -		/*
> -		 * Split those memory banks which are partially overlapping
> -		 * the vmalloc area greatly simplifying things later.
> -		 */
> -		if (!highmem && bank->size > size_limit) {
> -			if (meminfo.nr_banks >= NR_BANKS) {
> -				printk(KERN_CRIT "NR_BANKS too low, "
> -						 "ignoring high memory\n");
> -			} else {
> -				memmove(bank + 1, bank,
> -					(meminfo.nr_banks - i) * sizeof(*bank));
> -				meminfo.nr_banks++;
> -				i++;
> -				bank[1].size -= size_limit;
> -				bank[1].start = vmalloc_limit;
> -				bank[1].highmem = highmem = 1;
> -				j++;
> +		if (!IS_ENABLED(CONFIG_HIGHMEM) || cache_is_vipt_aliasing()) {
> +
> +			if (highmem) {
> +				pr_notice("Ignoring ram at %pa-%pa (!CONFIG_HIGHMEM)\n",
> +					&block_start, &block_end);
> +				memblock_remove(block_start, block_end);

The wrong size is used here, should be => memblock_remove(block_start, reg->size);
or => memblock_remove(block_start, size_limit);

> +				continue;
>   			}
> -			bank->size = size_limit;
> -		}
> -#else
> -		/*
> -		 * Highmem banks not allowed with !CONFIG_HIGHMEM.
> -		 */
> -		if (highmem) {
> -			printk(KERN_NOTICE "Ignoring RAM at %.8llx-%.8llx "
> -			       "(!CONFIG_HIGHMEM).\n",
> -			       (unsigned long long)bank->start,
> -			       (unsigned long long)bank->start + bank->size - 1);
> -			continue;
> -		}
>   
> -		/*
> -		 * Check whether this memory bank would partially overlap
> -		 * the vmalloc area.
> -		 */
> -		if (bank->size > size_limit) {
> -			printk(KERN_NOTICE "Truncating RAM at %.8llx-%.8llx "
> -			       "to -%.8llx (vmalloc region overlap).\n",
> -			       (unsigned long long)bank->start,
> -			       (unsigned long long)bank->start + bank->size - 1,
> -			       (unsigned long long)bank->start + size_limit - 1);
> -			bank->size = size_limit;
> +			if (reg->size > size_limit) {
> +				phys_addr_t overlap_size = reg->size - size_limit;
> +
> +				pr_notice("Truncating RAM at %pa-%pa to -%pa",
> +					&block_start, &block_end, &overlap_size);

Pls, change it back to show new RAM limit instead of size.
pr_notice("Truncating RAM at %pa-%pa to -%pa",
				&block_start, &block_end, &vmalloc_limit);

> +				memblock_remove(vmalloc_limit, overlap_size);
> +				block_end = vmalloc_limit;
> +			}
>   		}
> -#endif
> -		if (!bank->highmem) {
> -			phys_addr_t bank_end = bank->start + bank->size;
>   
> -			if (bank_end > arm_lowmem_limit)
> -				arm_lowmem_limit = bank_end;
> +		if (!highmem) {
> +			if (block_end > arm_lowmem_limit)
> +				arm_lowmem_limit = reg->base + size_limit;
> +

if !highmem then size_limit will be calculated as vmalloc_limit - reg->base
which in turn can be greater than reg->size. So, arm_lowmem_limit can point on
non existent memory address.

Seems, it should be:
  arm_lowmem_limit = block_end;

>   
>   			/*
>   			 * Find the first non-section-aligned page, and point
> @@ -1129,35 +1099,16 @@ void __init sanity_check_meminfo(void)
>   			 * occurs before any free memory is mapped.
>   			 */
>   			if (!memblock_limit) {
> -				if (!IS_ALIGNED(bank->start, SECTION_SIZE))
> -					memblock_limit = bank->start;
> -				else if (!IS_ALIGNED(bank_end, SECTION_SIZE))
> -					memblock_limit = bank_end;
[...]

Thanks for your patience :)

Regards,
-grygorii