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

Grygorii Strashko
2014-02-12T14:15:41Z

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 <jason@lakedaemon.net>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
> Tested-by: Leif Lindholm <leif.lindholm@linaro.org>
> Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
> ---
> 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@0x80000000 size@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