linux-kernel - Re: [PATCH 03/14] x86-32, NUMA: Remove redundant top-down alloc code from remap initialization

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Message-ID: <4D9B5361.3030501@kernel.org>
Date:	Tue, 05 Apr 2011 10:37:37 -0700
From:	Yinghai Lu <yinghai@...nel.org>
To:	Tejun Heo <tj@...nel.org>
CC:	mingo@...hat.com, hpa@...or.com, tglx@...utronix.de,
	rientjes@...gle.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/14] x86-32, NUMA: Remove redundant top-down alloc code
 from remap initialization

On 04/04/2011 03:23 PM, Tejun Heo wrote:
> memblock_find_in_range() now does top-down allocation by default, so
> there's no reason for its callers to explicitly implement it by
> gradually lowering the start address.
>
> Remove redundant top-down allocation logic from init_meminit() and
> calculate_numa_remap_pages().
>
> Signed-off-by: Tejun Heo<tj@...nel.org>
> Cc: Yinghai Lu<yinghai@...nel.org>
> Cc: David Rientjes<rientjes@...gle.com>
> Cc: Thomas Gleixner<tglx@...utronix.de
> Cc: Ingo Molnar<mingo@...hat.com>
> Cc: "H. Peter Anvin"<hpa@...or.com>
> ---
>   arch/x86/mm/numa_32.c |   43 ++++++++++++++-----------------------------
>   1 files changed, 14 insertions(+), 29 deletions(-)
>
> diff --git a/arch/x86/mm/numa_32.c b/arch/x86/mm/numa_32.c
> index 50e8250..60701a5 100644
> --- a/arch/x86/mm/numa_32.c
> +++ b/arch/x86/mm/numa_32.c
> @@ -270,8 +270,7 @@ static __init unsigned long calculate_numa_remap_pages(void)
>   	unsigned long size, reserve_pages = 0;
>
>   	for_each_online_node(nid) {
> -		u64 node_kva_target;
> -		u64 node_kva_final;
> +		u64 node_kva;
>
>   		/*
>   		 * The acpi/srat node info can show hot-add memroy zones
> @@ -295,19 +294,11 @@ static __init unsigned long calculate_numa_remap_pages(void)
>   		/* now the roundup is correct, convert to PAGE_SIZE pages */
>   		size = size * PTRS_PER_PTE;
>
> -		node_kva_target = round_down(node_end_pfn[nid] - size,
> -						 PTRS_PER_PTE);
> -		node_kva_target<<= PAGE_SHIFT;
> -		do {
> -			node_kva_final = memblock_find_in_range(node_kva_target,
> +		node_kva = memblock_find_in_range(node_start_pfn[nid]<<  PAGE_SHIFT,
>   					((u64)node_end_pfn[nid])<<PAGE_SHIFT,
> -						((u64)size)<<PAGE_SHIFT,
> -						LARGE_PAGE_BYTES);
> -			node_kva_target -= LARGE_PAGE_BYTES;
> -		} while (node_kva_final == MEMBLOCK_ERROR&&
> -			 (node_kva_target>>PAGE_SHIFT)>  (node_start_pfn[nid]));
> -
> -		if (node_kva_final == MEMBLOCK_ERROR)
> +					((u64)size)<<PAGE_SHIFT,
> +					LARGE_PAGE_BYTES);
> +		if (node_kva == MEMBLOCK_ERROR)
>   			panic("Can not get kva ram\n");
>
>   		node_remap_size[nid] = size;
> @@ -315,7 +306,7 @@ static __init unsigned long calculate_numa_remap_pages(void)
>   		reserve_pages += size;
>   		printk(KERN_DEBUG "Reserving %ld pages of KVA for lmem_map of"
>   				  " node %d at %llx\n",
> -				size, nid, node_kva_final>>PAGE_SHIFT);
> +				size, nid, node_kva>>  PAGE_SHIFT);
>
>   		/*
>   		 *  prevent kva address below max_low_pfn want it on system
> @@ -328,11 +319,11 @@ static __init unsigned long calculate_numa_remap_pages(void)
>   		 *  to use it as free.
>   		 *  So memblock_x86_reserve_range here, hope we don't run out of that array
>   		 */
> -		memblock_x86_reserve_range(node_kva_final,
> -			      node_kva_final+(((u64)size)<<PAGE_SHIFT),
> -			      "KVA RAM");
> +		memblock_x86_reserve_range(node_kva,
> +					   node_kva + (((u64)size)<<PAGE_SHIFT),
> +					   "KVA RAM");
>
> -		node_remap_start_pfn[nid] = node_kva_final>>PAGE_SHIFT;
> +		node_remap_start_pfn[nid] = node_kva>>  PAGE_SHIFT;
>   	}
>   	printk(KERN_INFO "Reserving total of %lx pages for numa KVA remap\n",
>   			reserve_pages);
> @@ -356,7 +347,6 @@ static void init_remap_allocator(int nid)
>   void __init initmem_init(void)
>   {
>   	int nid;
> -	long kva_target_pfn;
>
>   	/*
>   	 * When mapping a NUMA machine we allocate the node_mem_map arrays
> @@ -371,15 +361,10 @@ void __init initmem_init(void)
>
>   	kva_pages = roundup(calculate_numa_remap_pages(), PTRS_PER_PTE);
>
> -	kva_target_pfn = round_down(max_low_pfn - kva_pages, PTRS_PER_PTE);
> -	do {
> -		kva_start_pfn = memblock_find_in_range(kva_target_pfn<<PAGE_SHIFT,
> -					max_low_pfn<<PAGE_SHIFT,
> -					kva_pages<<PAGE_SHIFT,
> -					PTRS_PER_PTE<<PAGE_SHIFT)>>  PAGE_SHIFT;
> -		kva_target_pfn -= PTRS_PER_PTE;
> -	} while (kva_start_pfn == MEMBLOCK_ERROR&&  kva_target_pfn>  min_low_pfn);
> -
> +	kva_start_pfn = memblock_find_in_range(min_low_pfn<<  PAGE_SHIFT,
> +				max_low_pfn<<  PAGE_SHIFT,
> +				kva_pages<<  PAGE_SHIFT,
> +				PTRS_PER_PTE<<  PAGE_SHIFT)>>  PAGE_SHIFT;
>   	if (kva_start_pfn == MEMBLOCK_ERROR)
>   		panic("Can not get kva space\n");
>

Acked-by: Yinghai Lu <yinghai@...nel.org>
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