Re: [igt-dev] [PATCH i-g-t 2/6] aubdump: Add bitmap to track gtt pages that have been mapped

[Scott D Phillips <scott.d.phillips@intel.com>]

Jordan Justen <jordan.l.justen@intel.com> writes:

> This will allow us to map ranges as they are used, but prevents
> remapping already mapped regions.
>
> By mapping ranges as they are used, we can support pinned pages
> without having to map all pages of the first 32-bits.
>
> Cc: Scott D Phillips <scott.d.phillips@intel.com>
> Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
> ---
>  tools/aubdump.c | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 74 insertions(+), 1 deletion(-)
>
> diff --git a/tools/aubdump.c b/tools/aubdump.c
> index 2e60e547..661509e3 100644
> --- a/tools/aubdump.c
> +++ b/tools/aubdump.c
> @@ -383,7 +383,7 @@ register_write_out(uint32_t addr, uint32_t value)
>  }
>  
>  static void
> -gen8_map_range(uint64_t start, uint64_t end)
> +gen8_emit_pte_for_range(uint64_t start, uint64_t end)
>  {
>  	uint64_t entry_addr;
>  	uint64_t page_num;
> @@ -411,6 +411,79 @@ gen8_map_range(uint64_t start, uint64_t end)
>  	} while (entry_addr < end);
>  }
>  
> +static uint32_t*
> +get_mapped_bitmap()
> +{
> +	static uint32_t *bitmap = NULL;
> +	if (bitmap == NULL)
> +		bitmap = calloc(0x100000000 / 0x1000 / 32, sizeof(*bitmap));
> +	return bitmap;
> +}
> +
> +static void
> +set_mapped(uint64_t start, uint64_t end)
> +{
> +	uint64_t addr;
> +	uint32_t *bitmap = get_mapped_bitmap();
> +	if (bitmap == NULL)
> +		return;
> +
> +	addr = start & ~(4096 - 1);
> +	while (addr < end) {
> +		const uint32_t bit = 1 << ((addr >> 12) & 0x1f);
> +		if (bit == 1 && (end - addr) > 32 * 4096) {
> +			bitmap[addr >> 17] = 0xffffffff;
> +			addr += 32 * 4096;
> +		} else {
> +			bitmap[addr >> 17] |= bit;
> +			addr += 4096;
> +		}
> +	}
> +}
> +
> +static void
> +gen8_map_range(uint64_t start, uint64_t end)
> +{
> +	uint64_t addr1, addr2;
> +	uint32_t *bitmap = get_mapped_bitmap();
> +	if (bitmap == NULL)
> +		return;
> +
> +	addr1 = addr2 = start & ~(4096 - 1);
> +	while (addr2 < end) {
> +		while (addr1 < end) {
> +			const uint32_t dw = bitmap[addr1 >> 17];
> +			const uint32_t bit = 1 << ((addr1 >> 12) & 0x1f);
> +			if ((dw & bit) == 0)
> +				break;
> +			else if (bit == 1 && dw == 0xffffffff)
> +				addr1 += 32 * 4096;
> +			else
> +				addr1 += 4096;
> +		}
> +		if (addr1 >= end)
> +			break;
> +
> +		addr2 = addr1;
> +		while (addr2 < end) {
> +			const uint32_t dw = bitmap[addr2 >> 17];
> +			const uint32_t bit = 1 << ((addr2 >> 12) & 0x1f);
> +			if ((dw & bit) != 0)
> +				break;
> +			else if (bit == 1 && dw == 0)
> +				addr2 += 32 * 4096;
> +			else
> +				addr2 += 4096;
> +		}
> +		if (addr2 > end)
> +			addr2 = (end + 4096 - 1) & ~(4096 - 1);

you could use ALIGN() here too. I wouldn't say no to a macro for the
searches above if you want and it doesn't get too ugly.

Reviewed-by: Scott D Phillips <scott.d.phillips@intel.com>

> +		gen8_emit_pte_for_range(addr1, addr2);
> +		set_mapped(addr1, addr2);
> +		addr1 = addr2;
> +	}
> +}
> +
>  static void
>  gen10_write_header(void)
>  {
> -- 
> 2.16.1
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