Re: [PATCH] mm: remove unnecessary ia64 code and comment

[Mike Rapoport <rppt@kernel.org>]

On Fri, Dec 22, 2023 at 03:02:03PM +0800, Kefeng Wang wrote:
> IA64 has gone with commit cf8e8658100d ("arch: Remove
> Itanium (IA-64) architecture"), remove unnecessary ia64
> special mm code and comment too.
> 
> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>

Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>

> ---
>  mm/Kconfig      |  2 +-
>  mm/memory.c     |  4 +---
>  mm/mm_init.c    | 48 +++++++++++++++++++-----------------------------
>  mm/page_owner.c |  1 -
>  4 files changed, 21 insertions(+), 34 deletions(-)
> 
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 7824eeb53f7a..a6e1c51959c0 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -732,7 +732,7 @@ config DEFAULT_MMAP_MIN_ADDR
>  	  from userspace allocation.  Keeping a user from writing to low pages
>  	  can help reduce the impact of kernel NULL pointer bugs.
>  
> -	  For most ia64, ppc64 and x86 users with lots of address space
> +	  For most ppc64 and x86 users with lots of address space
>  	  a value of 65536 is reasonable and should cause no problems.
>  	  On arm and other archs it should not be higher than 32768.
>  	  Programs which use vm86 functionality or have some need to map
> diff --git a/mm/memory.c b/mm/memory.c
> index 716648268fed..86ca40a3f681 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -123,9 +123,7 @@ static bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf)
>  /*
>   * A number of key systems in x86 including ioremap() rely on the assumption
>   * that high_memory defines the upper bound on direct map memory, then end
> - * of ZONE_NORMAL.  Under CONFIG_DISCONTIG this means that max_low_pfn and
> - * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
> - * and ZONE_HIGHMEM.
> + * of ZONE_NORMAL.
>   */
>  void *high_memory;
>  EXPORT_SYMBOL(high_memory);
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index ac3d911c34fd..2390dca94d70 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -1467,8 +1467,7 @@ void __init set_pageblock_order(void)
>  
>  	/*
>  	 * Assume the largest contiguous order of interest is a huge page.
> -	 * This value may be variable depending on boot parameters on IA64 and
> -	 * powerpc.
> +	 * This value may be variable depending on boot parameters on powerpc.
>  	 */
>  	pageblock_order = order;
>  }
> @@ -1629,8 +1628,8 @@ void __init *memmap_alloc(phys_addr_t size, phys_addr_t align,
>  #ifdef CONFIG_FLATMEM
>  static void __init alloc_node_mem_map(struct pglist_data *pgdat)
>  {
> -	unsigned long __maybe_unused start = 0;
> -	unsigned long __maybe_unused offset = 0;
> +	unsigned long start, offset, size, end;
> +	struct page *map;
>  
>  	/* Skip empty nodes */
>  	if (!pgdat->node_spanned_pages)
> @@ -1638,33 +1637,24 @@ static void __init alloc_node_mem_map(struct pglist_data *pgdat)
>  
>  	start = pgdat->node_start_pfn & ~(MAX_ORDER_NR_PAGES - 1);
>  	offset = pgdat->node_start_pfn - start;
> -	/* ia64 gets its own node_mem_map, before this, without bootmem */
> -	if (!pgdat->node_mem_map) {
> -		unsigned long size, end;
> -		struct page *map;
> -
> -		/*
> -		 * The zone's endpoints aren't required to be MAX_ORDER
> -		 * aligned but the node_mem_map endpoints must be in order
> -		 * for the buddy allocator to function correctly.
> -		 */
> -		end = pgdat_end_pfn(pgdat);
> -		end = ALIGN(end, MAX_ORDER_NR_PAGES);
> -		size =  (end - start) * sizeof(struct page);
> -		map = memmap_alloc(size, SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
> -				   pgdat->node_id, false);
> -		if (!map)
> -			panic("Failed to allocate %ld bytes for node %d memory map\n",
> -			      size, pgdat->node_id);
> -		pgdat->node_mem_map = map + offset;
> -	}
> -	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
> -				__func__, pgdat->node_id, (unsigned long)pgdat,
> -				(unsigned long)pgdat->node_mem_map);
> -#ifndef CONFIG_NUMA
>  	/*
> -	 * With no DISCONTIG, the global mem_map is just set as node 0's
> +	 * The zone's endpoints aren't required to be MAX_ORDER
> +	 * aligned but the node_mem_map endpoints must be in order
> +	 * for the buddy allocator to function correctly.
>  	 */
> +	end = ALIGN(pgdat_end_pfn(pgdat), MAX_ORDER_NR_PAGES);
> +	size =  (end - start) * sizeof(struct page);
> +	map = memmap_alloc(size, SMP_CACHE_BYTES, MEMBLOCK_LOW_LIMIT,
> +			   pgdat->node_id, false);
> +	if (!map)
> +		panic("Failed to allocate %ld bytes for node %d memory map\n",
> +		      size, pgdat->node_id);
> +	pgdat->node_mem_map = map + offset;
> +	pr_debug("%s: node %d, pgdat %08lx, node_mem_map %08lx\n",
> +		 __func__, pgdat->node_id, (unsigned long)pgdat,
> +		 (unsigned long)pgdat->node_mem_map);
> +#ifndef CONFIG_NUMA
> +	/* the global mem_map is just set as node 0's */
>  	if (pgdat == NODE_DATA(0)) {
>  		mem_map = NODE_DATA(0)->node_mem_map;
>  		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index e7eba7688881..040dbf26a986 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -121,7 +121,6 @@ static noinline depot_stack_handle_t save_stack(gfp_t flags)
>  	 * Sometimes page metadata allocation tracking requires more
>  	 * memory to be allocated:
>  	 * - when new stack trace is saved to stack depot
> -	 * - when backtrace itself is calculated (ia64)
>  	 */
>  	if (current->in_page_owner)
>  		return dummy_handle;
> -- 
> 2.27.0
> 
> 

-- 
Sincerely yours,
Mike.