Re: [PATCH] swiotlb: Use page alignment for early buffer allocation

[Konrad Rzeszutek Wilk]

On Mon, Oct 11, 2010 at 10:40:25AM -0700, Yinghai Lu wrote:
> 
> We could call free_bootmem_late() if swiotlb is not used, and
> it will shrink to page alignment.
> 
> So alloc them with page alignment at first, to avoid lose two pages

Looks good to me. Fujita, you OK if I queue this up along with your
other patch (swiotlb: make io_tlb_overflow static)

> 
> before patch:
> [    0.000000]     memblock_x86_reserve_range: [00d3600000, 00d7600000]   swiotlb buffer
> [    0.000000]     memblock_x86_reserve_range: [00d7e7ef40, 00d7e9ef40]     swiotlb list
> [    0.000000]     memblock_x86_reserve_range: [00d7e3ef40, 00d7e7ef40]  swiotlb orig_ad
> [    0.000000]     memblock_x86_reserve_range: [000008a000, 0000092000]  swiotlb overflo
> 
> after patch will get
> [    0.000000]     memblock_x86_reserve_range: [00d3600000, 00d7600000]   swiotlb buffer
> [    0.000000]     memblock_x86_reserve_range: [00d7e7e000, 00d7e9e000]     swiotlb list
> [    0.000000]     memblock_x86_reserve_range: [00d7e3e000, 00d7e7e000]  swiotlb orig_ad
> [    0.000000]     memblock_x86_reserve_range: [000008a000, 0000092000]  swiotlb overflo
> 
> Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
> Cc: FUJITA Tomonori <fujita.tomonori@xxxxxxxxxxxxx>
> Cc: Becky Bruce <beckyb@xxxxxxxxxxxxxxxxxxx>
> 
> ---
>  lib/swiotlb.c |   16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> Index: linux-2.6/lib/swiotlb.c
> ===================================================================
> --- linux-2.6.orig/lib/swiotlb.c
> +++ linux-2.6/lib/swiotlb.c
> @@ -147,16 +147,16 @@ void __init swiotlb_init_with_tbl(char *
>  	 * to find contiguous free memory regions of size up to IO_TLB_SEGSIZE
>  	 * between io_tlb_start and io_tlb_end.
>  	 */
> -	io_tlb_list = alloc_bootmem(io_tlb_nslabs * sizeof(int));
> +	io_tlb_list = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
>  	for (i = 0; i < io_tlb_nslabs; i++)
>   		io_tlb_list[i] = IO_TLB_SEGSIZE - OFFSET(i, IO_TLB_SEGSIZE);
>  	io_tlb_index = 0;
> -	io_tlb_orig_addr = alloc_bootmem(io_tlb_nslabs * sizeof(phys_addr_t));
> +	io_tlb_orig_addr = alloc_bootmem_pages(PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
>  
>  	/*
>  	 * Get the overflow emergency buffer
>  	 */
> -	io_tlb_overflow_buffer = alloc_bootmem_low(io_tlb_overflow);
> +	io_tlb_overflow_buffer = alloc_bootmem_low_pages(PAGE_ALIGN(io_tlb_overflow));
>  	if (!io_tlb_overflow_buffer)
>  		panic("Cannot allocate SWIOTLB overflow buffer!\n");
>  	if (verbose)
> @@ -182,7 +182,7 @@ swiotlb_init_with_default_size(size_t de
>  	/*
>  	 * Get IO TLB memory from the low pages
>  	 */
> -	io_tlb_start = alloc_bootmem_low_pages(bytes);
> +	io_tlb_start = alloc_bootmem_low_pages(PAGE_ALIGN(bytes));
>  	if (!io_tlb_start)
>  		panic("Cannot allocate SWIOTLB buffer");
>  
> @@ -308,13 +308,13 @@ void __init swiotlb_free(void)
>  			   get_order(io_tlb_nslabs << IO_TLB_SHIFT));
>  	} else {
>  		free_bootmem_late(__pa(io_tlb_overflow_buffer),
> -				  io_tlb_overflow);
> +				  PAGE_ALIGN(io_tlb_overflow));
>  		free_bootmem_late(__pa(io_tlb_orig_addr),
> -				  io_tlb_nslabs * sizeof(phys_addr_t));
> +				  PAGE_ALIGN(io_tlb_nslabs * sizeof(phys_addr_t)));
>  		free_bootmem_late(__pa(io_tlb_list),
> -				  io_tlb_nslabs * sizeof(int));
> +				  PAGE_ALIGN(io_tlb_nslabs * sizeof(int)));
>  		free_bootmem_late(__pa(io_tlb_start),
> -				  io_tlb_nslabs << IO_TLB_SHIFT);
> +				  PAGE_ALIGN(io_tlb_nslabs << IO_TLB_SHIFT));
>  	}
>  }
>  
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