Subject: Re: [PATCH 03/21] mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option

From: Baoquan He <[email-masked]>
Date: Tue, 21 Apr 2020 17:45:30 +0800

On 04/21/20 at 12:09pm, Mike Rapoport wrote:
> > > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > > index fc0aad0bc1f5..e67dc501576a 100644
> > > --- a/mm/memory_hotplug.c
> > > +++ b/mm/memory_hotplug.c
> > > @@ -1372,11 +1372,7 @@ check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
> > >  
> > >  static int __init cmdline_parse_movable_node(char *p)
> > >  {
> > > -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > >  	movable_node_enabled = true;
> > > -#else
> > > -	pr_warn("movable_node parameter depends on CONFIG_HAVE_MEMBLOCK_NODE_MAP to work properly\n");
> > > -#endif
> > 
> > Wondering if this change will impact anything. Before, those ARCHes with
> > CONFIG_HAVE_MEMBLOCK_NODE_MAP support movable_node. With this patch
> > applied, those ARCHes which don't support CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > can also have 'movable_node' specified in kernel cmdline.
> > 
> > >  	return 0;
> > >  }
> > >  early_param("movable_node", cmdline_parse_movable_node);
> > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > > index 1ac775bfc9cf..4530e9cfd9f7 100644
> > > --- a/mm/page_alloc.c
> > > +++ b/mm/page_alloc.c
> > > @@ -335,7 +335,6 @@ static unsigned long nr_kernel_pages __initdata;
> > >  static unsigned long nr_all_pages __initdata;
> > >  static unsigned long dma_reserve __initdata;
> > >  
> > > -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > >  static unsigned long arch_zone_lowest_possible_pfn[MAX_NR_ZONES] __initdata;
> > >  static unsigned long arch_zone_highest_possible_pfn[MAX_NR_ZONES] __initdata;
> > >  static unsigned long required_kernelcore __initdata;
> > 
> > Does it mean those ARCHes which don't support
> > CONFIG_HAVE_MEMBLOCK_NODE_MAP before, will have 'kernelcore=' and
> > 'movablecore=' now, and will have MOVABLE zone?
> 
> I hesitated a lot about whether to hide the kernelcore/movablecore and
> related code behind an #ifdef.
> In the end I've decided to keep the code compiled unconditionally as it
> is anyway __init and no sane person would pass "kernelcore=" to the
> kernel on a UMA system.

I see. Then maybe can do something if someone complains about it
in the future, e.g warn out with a message in
cmdline_parse_movable_node(), cmdline_parse_kernelcore().

> 
> > > @@ -348,7 +347,6 @@ static bool mirrored_kernelcore __meminitdata;
> > >  /* movable_zone is the "real" zone pages in ZONE_MOVABLE are taken from */
> > >  int movable_zone;
> > >  EXPORT_SYMBOL(movable_zone);
> > > -#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> > >  
> > >  #if MAX_NUMNODES > 1
> > >  unsigned int nr_node_ids __read_mostly = MAX_NUMNODES;
> > > @@ -1499,8 +1497,7 @@ void __free_pages_core(struct page *page, unsigned int order)
> > >  	__free_pages(page, order);
> > >  }
> > >  
> > > -#if defined(CONFIG_HAVE_ARCH_EARLY_PFN_TO_NID) || \
> > > -	defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP)
> > > +#ifdef CONFIG_NEED_MULTIPLE_NODES
> > >  
> > >  static struct mminit_pfnnid_cache early_pfnnid_cache __meminitdata;
> > >  
> > > @@ -1542,7 +1539,7 @@ int __meminit early_pfn_to_nid(unsigned long pfn)
> > >  
> > >  	return nid;
> > >  }
> > > -#endif
> > > +#endif /* CONFIG_NEED_MULTIPLE_NODES */
> > >  
> > >  #ifdef CONFIG_NODES_SPAN_OTHER_NODES
> > >  /* Only safe to use early in boot when initialisation is single-threaded */
> > > @@ -5924,7 +5921,6 @@ void __ref build_all_zonelists(pg_data_t *pgdat)
> > >  static bool __meminit
> > >  overlap_memmap_init(unsigned long zone, unsigned long *pfn)
> > >  {
> > > -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > >  	static struct memblock_region *r;
> > >  
> > >  	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
> > > @@ -5940,7 +5936,6 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn)
> > >  			return true;
> > >  		}
> > >  	}
> > > -#endif
> > >  	return false;
> > >  }
> > >  
> > > @@ -6573,8 +6568,7 @@ static unsigned long __init zone_absent_pages_in_node(int nid,
> > >  	return nr_absent;
> > >  }
> > >  
> > > -#else /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> > > -static inline unsigned long __init zone_spanned_pages_in_node(int nid,
> > > +static inline unsigned long __init compat_zone_spanned_pages_in_node(int nid,
> > 
> > Is it compact zone which has continuous memory region, and the
> > compat here is typo? Or it's compatible zone? The name seems a little
> > confusing, or I miss something.
> 
> It's 'compat' from 'compatibility'. This is kinda "the old way" and the
> version that was defined when CONFIG_HAVE_MEMBLOCK_NODE_MAP=y is the
> "new way", so I picked 'compat' for backwards compatibility. 
> Anyway, it will go away later in pacth 19. 

Got it, thanks for telling.

> 
> > >  					unsigned long zone_type,
> > >  					unsigned long node_start_pfn,
> > >  					unsigned long node_end_pfn,
> > > @@ -6593,7 +6587,7 @@ static inline unsigned long __init zone_spanned_pages_in_node(int nid,
> > >  	return zones_size[zone_type];
> > >  }
> > >  
> > > -static inline unsigned long __init zone_absent_pages_in_node(int nid,
> > > +static inline unsigned long __init compat_zone_absent_pages_in_node(int nid,
> > >  						unsigned long zone_type,
> > >  						unsigned long node_start_pfn,
> > >  						unsigned long node_end_pfn,
> > > @@ -6605,13 +6599,12 @@ static inline unsigned long __init zone_absent_pages_in_node(int nid,
> > >  	return zholes_size[zone_type];
> > >  }
> > >  
> > > -#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> > > -
> > >  static void __init calculate_node_totalpages(struct pglist_data *pgdat,
> > >  						unsigned long node_start_pfn,
> > >  						unsigned long node_end_pfn,
> > >  						unsigned long *zones_size,
> > > -						unsigned long *zholes_size)
> > > +						unsigned long *zholes_size,
> > > +						bool compat)
> > >  {
> > >  	unsigned long realtotalpages = 0, totalpages = 0;
> > >  	enum zone_type i;
> > > @@ -6619,17 +6612,38 @@ static void __init calculate_node_totalpages(struct pglist_data *pgdat,
> > >  	for (i = 0; i < MAX_NR_ZONES; i++) {
> > >  		struct zone *zone = pgdat->node_zones + i;
> > >  		unsigned long zone_start_pfn, zone_end_pfn;
> > > +		unsigned long spanned, absent;
> > >  		unsigned long size, real_size;
> > >  
> > > -		size = zone_spanned_pages_in_node(pgdat->node_id, i,
> > > -						  node_start_pfn,
> > > -						  node_end_pfn,
> > > -						  &zone_start_pfn,
> > > -						  &zone_end_pfn,
> > > -						  zones_size);
> > > -		real_size = size - zone_absent_pages_in_node(pgdat->node_id, i,
> > > -						  node_start_pfn, node_end_pfn,
> > > -						  zholes_size);
> > > +		if (compat) {
> > > +			spanned = compat_zone_spanned_pages_in_node(
> > > +						pgdat->node_id, i,
> > > +						node_start_pfn,
> > > +						node_end_pfn,
> > > +						&zone_start_pfn,
> > > +						&zone_end_pfn,
> > > +						zones_size);
> > > +			absent = compat_zone_absent_pages_in_node(
> > > +						pgdat->node_id, i,
> > > +						node_start_pfn,
> > > +						node_end_pfn,
> > > +						zholes_size);
> > > +		} else {
> > > +			spanned = zone_spanned_pages_in_node(pgdat->node_id, i,
> > > +						node_start_pfn,
> > > +						node_end_pfn,
> > > +						&zone_start_pfn,
> > > +						&zone_end_pfn,
> > > +						zones_size);
> > > +			absent = zone_absent_pages_in_node(pgdat->node_id, i,
> > > +						node_start_pfn,
> > > +						node_end_pfn,
> > > +						zholes_size);
> > > +		}
> > > +
> > > +		size = spanned;
> > > +		real_size = size - absent;
> > > +
> > >  		if (size)
> > >  			zone->zone_start_pfn = zone_start_pfn;
> > >  		else
> > > @@ -6929,10 +6943,8 @@ static void __ref alloc_node_mem_map(struct pglist_data *pgdat)
> > >  	 */
> > >  	if (pgdat == NODE_DATA(0)) {
> > >  		mem_map = NODE_DATA(0)->node_mem_map;
> > > -#if defined(CONFIG_HAVE_MEMBLOCK_NODE_MAP) || defined(CONFIG_FLATMEM)
> > >  		if (page_to_pfn(mem_map) != pgdat->node_start_pfn)
> > >  			mem_map -= offset;
> > > -#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> > >  	}
> > >  #endif
> > >  }
> > > @@ -6949,9 +6961,10 @@ static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
> > >  static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
> > >  #endif
> > >  
> > > -void __init free_area_init_node(int nid, unsigned long *zones_size,
> > > -				   unsigned long node_start_pfn,
> > > -				   unsigned long *zholes_size)
> > > +static void __init __free_area_init_node(int nid, unsigned long *zones_size,
> > > +					 unsigned long node_start_pfn,
> > > +					 unsigned long *zholes_size,
> > > +					 bool compat)
> > >  {
> > >  	pg_data_t *pgdat = NODE_DATA(nid);
> > >  	unsigned long start_pfn = 0;
> > > @@ -6963,16 +6976,16 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> > >  	pgdat->node_id = nid;
> > >  	pgdat->node_start_pfn = node_start_pfn;
> > >  	pgdat->per_cpu_nodestats = NULL;
> > > -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > > -	get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
> > > -	pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
> > > -		(u64)start_pfn << PAGE_SHIFT,
> > > -		end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
> > > -#else
> > > -	start_pfn = node_start_pfn;
> > > -#endif
> > > +	if (!compat) {
> > > +		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
> > > +		pr_info("Initmem setup node %d [mem %#018Lx-%#018Lx]\n", nid,
> > > +			(u64)start_pfn << PAGE_SHIFT,
> > > +			end_pfn ? ((u64)end_pfn << PAGE_SHIFT) - 1 : 0);
> > > +	} else {
> > > +		start_pfn = node_start_pfn;
> > > +	}
> > >  	calculate_node_totalpages(pgdat, start_pfn, end_pfn,
> > > -				  zones_size, zholes_size);
> > > +				  zones_size, zholes_size, compat);
> > >  
> > >  	alloc_node_mem_map(pgdat);
> > >  	pgdat_set_deferred_range(pgdat);
> > > @@ -6980,6 +6993,14 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> > >  	free_area_init_core(pgdat);
> > >  }
> > >  
> > > +void __init free_area_init_node(int nid, unsigned long *zones_size,
> > > +				unsigned long node_start_pfn,
> > > +				unsigned long *zholes_size)
> > > +{
> > > +	__free_area_init_node(nid, zones_size, node_start_pfn, zholes_size,
> > > +			      true);
> > > +}
> > > +
> > >  #if !defined(CONFIG_FLAT_NODE_MEM_MAP)
> > >  /*
> > >   * Initialize all valid struct pages in the range [spfn, epfn) and mark them
> > > @@ -7063,8 +7084,6 @@ static inline void __init init_unavailable_mem(void)
> > >  }
> > >  #endif /* !CONFIG_FLAT_NODE_MEM_MAP */
> > >  
> > > -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> > > -
> > >  #if MAX_NUMNODES > 1
> > >  /*
> > >   * Figure out the number of possible node ids.
> > > @@ -7493,8 +7512,8 @@ void __init free_area_init_nodes(unsigned long *max_zone_pfn)
> > >  	init_unavailable_mem();
> > >  	for_each_online_node(nid) {
> > >  		pg_data_t *pgdat = NODE_DATA(nid);
> > > -		free_area_init_node(nid, NULL,
> > > -				find_min_pfn_for_node(nid), NULL);
> > > +		__free_area_init_node(nid, NULL,
> > > +				      find_min_pfn_for_node(nid), NULL, false);
> > >  
> > >  		/* Any memory on that node */
> > >  		if (pgdat->node_present_pages)
> > > @@ -7559,8 +7578,6 @@ static int __init cmdline_parse_movablecore(char *p)
> > >  early_param("kernelcore", cmdline_parse_kernelcore);
> > >  early_param("movablecore", cmdline_parse_movablecore);
> > >  
> > > -#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
> > > -
> > >  void adjust_managed_page_count(struct page *page, long count)
> > >  {
> > >  	atomic_long_add(count, &page_zone(page)->managed_pages);
> > > -- 
> > > 2.25.1
> > > 
> > 
> 
> -- 
> Sincerely yours,
> Mike.
>