diff mbox

[v2,2/2] mm/sparse: start using sparse_init_nid(), and remove old code

Message ID 20180630030944.9335-3-pasha.tatashin@oracle.com
State New, archived
Headers show

Commit Message

Pavel Tatashin June 30, 2018, 3:09 a.m. UTC
Change sprase_init() to only find the pnum ranges that belong to a specific
node and call sprase_init_nid() for that range from sparse_init().

Delete all the code that became obsolete with this change.

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
---
 include/linux/mm.h  |   5 -
 mm/sparse-vmemmap.c |  39 --------
 mm/sparse.c         | 223 ++++----------------------------------------
 3 files changed, 17 insertions(+), 250 deletions(-)

Comments

Baoquan He July 2, 2018, 1:34 a.m. UTC | #1
Hi Pavel,

On 06/29/18 at 11:09pm, Pavel Tatashin wrote:
> Change sprase_init() to only find the pnum ranges that belong to a specific
> node and call sprase_init_nid() for that range from sparse_init().
> 
> Delete all the code that became obsolete with this change.

> @@ -617,87 +491,24 @@ void __init sparse_init_nid(int nid, unsigned long pnum_begin,
>   */
>  void __init sparse_init(void)
>  {
> -	unsigned long pnum;
> -	struct page *map;
> -	struct page **map_map;
> -	unsigned long *usemap;
> -	unsigned long **usemap_map;
> -	int size, size2;
> -	int nr_consumed_maps = 0;
> -
> -	/* see include/linux/mmzone.h 'struct mem_section' definition */
> -	BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
> +	unsigned long pnum_begin = first_present_section_nr();
> +	int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
> +	unsigned long pnum_end, map_count = 1;
>  
> -	/* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
> -	set_pageblock_order();

Not very sure if removing set_pageblock_order() calling here is OK. What
if CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is enabled? usemap_size() depends
on value of 'pageblock_order'.

Thanks
Baoquan

> +	for_each_present_section_nr(pnum_begin + 1, pnum_end) {
> +		int nid = sparse_early_nid(__nr_to_section(pnum_end));
>  
> -	/*
> -	 * map is using big page (aka 2M in x86 64 bit)
> -	 * usemap is less one page (aka 24 bytes)
> -	 * so alloc 2M (with 2M align) and 24 bytes in turn will
> -	 * make next 2M slip to one more 2M later.
> -	 * then in big system, the memory will have a lot of holes...
> -	 * here try to allocate 2M pages continuously.
> -	 *
> -	 * powerpc need to call sparse_init_one_section right after each
> -	 * sparse_early_mem_map_alloc, so allocate usemap_map at first.
> -	 */
> -	size = sizeof(unsigned long *) * nr_present_sections;
> -	usemap_map = memblock_virt_alloc(size, 0);
> -	if (!usemap_map)
> -		panic("can not allocate usemap_map\n");
> -	alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
> -				(void *)usemap_map,
> -				sizeof(usemap_map[0]));
> -
> -	size2 = sizeof(struct page *) * nr_present_sections;
> -	map_map = memblock_virt_alloc(size2, 0);
> -	if (!map_map)
> -		panic("can not allocate map_map\n");
> -	alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
> -				(void *)map_map,
> -				sizeof(map_map[0]));
> -
> -	/* The numner of present sections stored in nr_present_sections
> -	 * are kept the same since mem sections are marked as present in
> -	 * memory_present(). In this for loop, we need check which sections
> -	 * failed to allocate memmap or usemap, then clear its
> -	 * ->section_mem_map accordingly. During this process, we need
> -	 * increase 'nr_consumed_maps' whether its allocation of memmap
> -	 * or usemap failed or not, so that after we handle the i-th
> -	 * memory section, can get memmap and usemap of (i+1)-th section
> -	 * correctly. */
> -	for_each_present_section_nr(0, pnum) {
> -		struct mem_section *ms;
> -
> -		if (nr_consumed_maps >= nr_present_sections) {
> -			pr_err("nr_consumed_maps goes beyond nr_present_sections\n");
> -			break;
> -		}
> -		ms = __nr_to_section(pnum);
> -		usemap = usemap_map[nr_consumed_maps];
> -		if (!usemap) {
> -			ms->section_mem_map = 0;
> -			nr_consumed_maps++;
> -			continue;
> -		}
> -
> -		map = map_map[nr_consumed_maps];
> -		if (!map) {
> -			ms->section_mem_map = 0;
> -			nr_consumed_maps++;
> +		if (nid == nid_begin) {
> +			map_count++;
>  			continue;
>  		}
> -
> -		sparse_init_one_section(__nr_to_section(pnum), pnum, map,
> -								usemap);
> -		nr_consumed_maps++;
> +		sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
> +		nid_begin = nid;
> +		pnum_begin = pnum_end;
> +		map_count = 1;
>  	}
> -
> +	sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
>  	vmemmap_populate_print_last();
> -
> -	memblock_free_early(__pa(map_map), size2);
> -	memblock_free_early(__pa(usemap_map), size);
>  }
>  
>  #ifdef CONFIG_MEMORY_HOTPLUG
> -- 
> 2.18.0
>
Baoquan He July 2, 2018, 1:39 a.m. UTC | #2
On 06/29/18 at 11:09pm, Pavel Tatashin wrote:
> Change sprase_init() to only find the pnum ranges that belong to a specific
> node and call sprase_init_nid() for that range from sparse_init().
> 
> Delete all the code that became obsolete with this change.
>  void __init sparse_init(void)
>  {
> -	unsigned long pnum;
> -	struct page *map;
> -	struct page **map_map;
> -	unsigned long *usemap;
> -	unsigned long **usemap_map;
> -	int size, size2;
> -	int nr_consumed_maps = 0;
> -
> -	/* see include/linux/mmzone.h 'struct mem_section' definition */
> -	BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
> +	unsigned long pnum_begin = first_present_section_nr();
> +	int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
> +	unsigned long pnum_end, map_count = 1;
>  
> -	/* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
> -	set_pageblock_order();
> +	for_each_present_section_nr(pnum_begin + 1, pnum_end) {
> +		int nid = sparse_early_nid(__nr_to_section(pnum_end));
>  
> -	/*
> -	 * map is using big page (aka 2M in x86 64 bit)
> -	 * usemap is less one page (aka 24 bytes)
> -	 * so alloc 2M (with 2M align) and 24 bytes in turn will
> -	 * make next 2M slip to one more 2M later.
> -	 * then in big system, the memory will have a lot of holes...
> -	 * here try to allocate 2M pages continuously.
> -	 *
> -	 * powerpc need to call sparse_init_one_section right after each
> -	 * sparse_early_mem_map_alloc, so allocate usemap_map at first.
> -	 */
> -	size = sizeof(unsigned long *) * nr_present_sections;
> -	usemap_map = memblock_virt_alloc(size, 0);
> -	if (!usemap_map)
> -		panic("can not allocate usemap_map\n");
> -	alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
> -				(void *)usemap_map,
> -				sizeof(usemap_map[0]));
> -
> -	size2 = sizeof(struct page *) * nr_present_sections;
> -	map_map = memblock_virt_alloc(size2, 0);
> -	if (!map_map)
> -		panic("can not allocate map_map\n");
> -	alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
> -				(void *)map_map,
> -				sizeof(map_map[0]));
> -
> -	/* The numner of present sections stored in nr_present_sections
> -	 * are kept the same since mem sections are marked as present in
> -	 * memory_present(). In this for loop, we need check which sections
> -	 * failed to allocate memmap or usemap, then clear its
> -	 * ->section_mem_map accordingly. During this process, we need
> -	 * increase 'nr_consumed_maps' whether its allocation of memmap
> -	 * or usemap failed or not, so that after we handle the i-th
> -	 * memory section, can get memmap and usemap of (i+1)-th section
> -	 * correctly. */
> -	for_each_present_section_nr(0, pnum) {
> -		struct mem_section *ms;
> -
> -		if (nr_consumed_maps >= nr_present_sections) {
> -			pr_err("nr_consumed_maps goes beyond nr_present_sections\n");
> -			break;
> -		}
> -		ms = __nr_to_section(pnum);
> -		usemap = usemap_map[nr_consumed_maps];
> -		if (!usemap) {
> -			ms->section_mem_map = 0;
> -			nr_consumed_maps++;
> -			continue;
> -		}
> -
> -		map = map_map[nr_consumed_maps];
> -		if (!map) {
> -			ms->section_mem_map = 0;
> -			nr_consumed_maps++;
> +		if (nid == nid_begin) {
> +			map_count++;
>  			continue;
>  		}
> -
> -		sparse_init_one_section(__nr_to_section(pnum), pnum, map,
> -								usemap);
> -		nr_consumed_maps++;
> +		sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
				~~~
Here, node id passed to sparse_init_nid() should be 'nid_begin', but not
'nid'. When you found out the current section's 'nid' is diferent than
'nid_begin', handle node 'nid_begin', then start to next node 'nid'.


> +		nid_begin = nid;
> +		pnum_begin = pnum_end;
> +		map_count = 1;
>  	}
> -
> +	sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
>  	vmemmap_populate_print_last();
> -
> -	memblock_free_early(__pa(map_map), size2);
> -	memblock_free_early(__pa(usemap_map), size);
>  }
>  
>  #ifdef CONFIG_MEMORY_HOTPLUG
> -- 
> 2.18.0
>
Pavel Tatashin July 2, 2018, 1:44 a.m. UTC | #3
On Sun, Jul 1, 2018 at 9:34 PM Baoquan He <bhe@redhat.com> wrote:
>
> Hi Pavel,
>
> On 06/29/18 at 11:09pm, Pavel Tatashin wrote:
> > Change sprase_init() to only find the pnum ranges that belong to a specific
> > node and call sprase_init_nid() for that range from sparse_init().
> >
> > Delete all the code that became obsolete with this change.
>
> > @@ -617,87 +491,24 @@ void __init sparse_init_nid(int nid, unsigned long pnum_begin,
> >   */
> >  void __init sparse_init(void)
> >  {
> > -     unsigned long pnum;
> > -     struct page *map;
> > -     struct page **map_map;
> > -     unsigned long *usemap;
> > -     unsigned long **usemap_map;
> > -     int size, size2;
> > -     int nr_consumed_maps = 0;
> > -
> > -     /* see include/linux/mmzone.h 'struct mem_section' definition */
> > -     BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
> > +     unsigned long pnum_begin = first_present_section_nr();
> > +     int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
> > +     unsigned long pnum_end, map_count = 1;
> >
> > -     /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
> > -     set_pageblock_order();
>
> Not very sure if removing set_pageblock_order() calling here is OK. What
> if CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is enabled? usemap_size() depends
> on value of 'pageblock_order'.

Hi Baoquan,

Nice catch, you are right, I incorrectly removed this call, will add
it back in the next version.

Pavel

>
> Thanks
> Baoquan
>
> > +     for_each_present_section_nr(pnum_begin + 1, pnum_end) {
> > +             int nid = sparse_early_nid(__nr_to_section(pnum_end));
> >
> > -     /*
> > -      * map is using big page (aka 2M in x86 64 bit)
> > -      * usemap is less one page (aka 24 bytes)
> > -      * so alloc 2M (with 2M align) and 24 bytes in turn will
> > -      * make next 2M slip to one more 2M later.
> > -      * then in big system, the memory will have a lot of holes...
> > -      * here try to allocate 2M pages continuously.
> > -      *
> > -      * powerpc need to call sparse_init_one_section right after each
> > -      * sparse_early_mem_map_alloc, so allocate usemap_map at first.
> > -      */
> > -     size = sizeof(unsigned long *) * nr_present_sections;
> > -     usemap_map = memblock_virt_alloc(size, 0);
> > -     if (!usemap_map)
> > -             panic("can not allocate usemap_map\n");
> > -     alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
> > -                             (void *)usemap_map,
> > -                             sizeof(usemap_map[0]));
> > -
> > -     size2 = sizeof(struct page *) * nr_present_sections;
> > -     map_map = memblock_virt_alloc(size2, 0);
> > -     if (!map_map)
> > -             panic("can not allocate map_map\n");
> > -     alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
> > -                             (void *)map_map,
> > -                             sizeof(map_map[0]));
> > -
> > -     /* The numner of present sections stored in nr_present_sections
> > -      * are kept the same since mem sections are marked as present in
> > -      * memory_present(). In this for loop, we need check which sections
> > -      * failed to allocate memmap or usemap, then clear its
> > -      * ->section_mem_map accordingly. During this process, we need
> > -      * increase 'nr_consumed_maps' whether its allocation of memmap
> > -      * or usemap failed or not, so that after we handle the i-th
> > -      * memory section, can get memmap and usemap of (i+1)-th section
> > -      * correctly. */
> > -     for_each_present_section_nr(0, pnum) {
> > -             struct mem_section *ms;
> > -
> > -             if (nr_consumed_maps >= nr_present_sections) {
> > -                     pr_err("nr_consumed_maps goes beyond nr_present_sections\n");
> > -                     break;
> > -             }
> > -             ms = __nr_to_section(pnum);
> > -             usemap = usemap_map[nr_consumed_maps];
> > -             if (!usemap) {
> > -                     ms->section_mem_map = 0;
> > -                     nr_consumed_maps++;
> > -                     continue;
> > -             }
> > -
> > -             map = map_map[nr_consumed_maps];
> > -             if (!map) {
> > -                     ms->section_mem_map = 0;
> > -                     nr_consumed_maps++;
> > +             if (nid == nid_begin) {
> > +                     map_count++;
> >                       continue;
> >               }
> > -
> > -             sparse_init_one_section(__nr_to_section(pnum), pnum, map,
> > -                                                             usemap);
> > -             nr_consumed_maps++;
> > +             sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
> > +             nid_begin = nid;
> > +             pnum_begin = pnum_end;
> > +             map_count = 1;
> >       }
> > -
> > +     sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
> >       vmemmap_populate_print_last();
> > -
> > -     memblock_free_early(__pa(map_map), size2);
> > -     memblock_free_early(__pa(usemap_map), size);
> >  }
> >
> >  #ifdef CONFIG_MEMORY_HOTPLUG
> > --
> > 2.18.0
> >
>
Pavel Tatashin July 2, 2018, 1:46 a.m. UTC | #4
~~~
> Here, node id passed to sparse_init_nid() should be 'nid_begin', but not
> 'nid'. When you found out the current section's 'nid' is diferent than
> 'nid_begin', handle node 'nid_begin', then start to next node 'nid'.

Thank you for reviewing this work. Here nid equals to nid_begin:

See, "if" at 501, and this call is at 505.

492 void __init sparse_init(void)
493 {
494         unsigned long pnum_begin = first_present_section_nr();
495         int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
496         unsigned long pnum_end, map_count = 1;
497
498         for_each_present_section_nr(pnum_begin + 1, pnum_end) {
499                 int nid = sparse_early_nid(__nr_to_section(pnum_end));
500
501                 if (nid == nid_begin) {
502                         map_count++;
503                         continue;
504                 }
505                 sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
506                 nid_begin = nid;
507                 pnum_begin = pnum_end;
508                 map_count = 1;
509         }
510         sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
511         vmemmap_populate_print_last();
512 }

Thank you,
Pavel
Baoquan He July 2, 2018, 1:52 a.m. UTC | #5
On 07/01/18 at 09:46pm, Pavel Tatashin wrote:
>                          ~~~
> > Here, node id passed to sparse_init_nid() should be 'nid_begin', but not
> > 'nid'. When you found out the current section's 'nid' is diferent than
> > 'nid_begin', handle node 'nid_begin', then start to next node 'nid'.
> 
> Thank you for reviewing this work. Here nid equals to nid_begin:
> 
> See, "if" at 501, and this call is at 505.

Yes, if they are equal at 501, 'continue' to for loop. If nid is not
equal to nid_begin, we execute sparse_init_nid(), here should it be that
nid_begin is the current node, nid is next node?

> 
> 492 void __init sparse_init(void)
> 493 {
> 494         unsigned long pnum_begin = first_present_section_nr();
> 495         int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
> 496         unsigned long pnum_end, map_count = 1;
> 497
> 498         for_each_present_section_nr(pnum_begin + 1, pnum_end) {
> 499                 int nid = sparse_early_nid(__nr_to_section(pnum_end));
> 500
> 501                 if (nid == nid_begin) {
> 502                         map_count++;
> 503                         continue;
> 504                 }
> 505                 sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
> 506                 nid_begin = nid;
> 507                 pnum_begin = pnum_end;
> 508                 map_count = 1;
> 509         }
> 510         sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
> 511         vmemmap_populate_print_last();
> 512 }
> 
> Thank you,
> Pavel
Pavel Tatashin July 2, 2018, 1:55 a.m. UTC | #6
>
> Yes, if they are equal at 501, 'continue' to for loop. If nid is not
> equal to nid_begin, we execute sparse_init_nid(), here should it be that
> nid_begin is the current node, nid is next node?

Nevermind, I forgot about the continue, I will fix it. Thank you again!

Pavel
diff mbox

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 85530fdfb1f2..a7438be90658 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2646,11 +2646,6 @@  extern int randomize_va_space;
 const char * arch_vma_name(struct vm_area_struct *vma);
 void print_vma_addr(char *prefix, unsigned long rip);
 
-void sparse_mem_maps_populate_node(struct page **map_map,
-				   unsigned long pnum_begin,
-				   unsigned long pnum_end,
-				   unsigned long map_count,
-				   int nodeid);
 struct page * sparse_populate_node(unsigned long pnum_begin,
 				   unsigned long pnum_end,
 				   unsigned long map_count,
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index b3e325962306..4edc877cfe82 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -273,45 +273,6 @@  struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid,
 	return map;
 }
 
-void __init sparse_mem_maps_populate_node(struct page **map_map,
-					  unsigned long pnum_begin,
-					  unsigned long pnum_end,
-					  unsigned long map_count, int nodeid)
-{
-	unsigned long pnum;
-	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
-	void *vmemmap_buf_start;
-	int nr_consumed_maps = 0;
-
-	size = ALIGN(size, PMD_SIZE);
-	vmemmap_buf_start = __earlyonly_bootmem_alloc(nodeid, size * map_count,
-			 PMD_SIZE, __pa(MAX_DMA_ADDRESS));
-
-	if (vmemmap_buf_start) {
-		vmemmap_buf = vmemmap_buf_start;
-		vmemmap_buf_end = vmemmap_buf_start + size * map_count;
-	}
-
-	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
-		if (!present_section_nr(pnum))
-			continue;
-
-		map_map[nr_consumed_maps] = sparse_mem_map_populate(pnum, nodeid, NULL);
-		if (map_map[nr_consumed_maps++])
-			continue;
-		pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
-		       __func__);
-	}
-
-	if (vmemmap_buf_start) {
-		/* need to free left buf */
-		memblock_free_early(__pa(vmemmap_buf),
-				    vmemmap_buf_end - vmemmap_buf);
-		vmemmap_buf = NULL;
-		vmemmap_buf_end = NULL;
-	}
-}
-
 struct page * __init sparse_populate_node(unsigned long pnum_begin,
 					  unsigned long pnum_end,
 					  unsigned long map_count,
diff --git a/mm/sparse.c b/mm/sparse.c
index c18d92b8ab9b..6361b7ff733d 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -200,11 +200,10 @@  static inline int next_present_section_nr(int section_nr)
 	      (section_nr <= __highest_present_section_nr));	\
 	     section_nr = next_present_section_nr(section_nr))
 
-/*
- * Record how many memory sections are marked as present
- * during system bootup.
- */
-static int __initdata nr_present_sections;
+static inline unsigned long first_present_section_nr(void)
+{
+	return next_present_section_nr(-1);
+}
 
 /* Record a memory area against a node. */
 void __init memory_present(int nid, unsigned long start, unsigned long end)
@@ -235,7 +234,6 @@  void __init memory_present(int nid, unsigned long start, unsigned long end)
 			ms->section_mem_map = sparse_encode_early_nid(nid) |
 							SECTION_IS_ONLINE;
 			section_mark_present(ms);
-			nr_present_sections++;
 		}
 	}
 }
@@ -377,34 +375,6 @@  static void __init check_usemap_section_nr(int nid, unsigned long *usemap)
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
-static void __init sparse_early_usemaps_alloc_node(void *data,
-				 unsigned long pnum_begin,
-				 unsigned long pnum_end,
-				 unsigned long usemap_count, int nodeid)
-{
-	void *usemap;
-	unsigned long pnum;
-	unsigned long **usemap_map = (unsigned long **)data;
-	int size = usemap_size();
-	int nr_consumed_maps = 0;
-
-	usemap = sparse_early_usemaps_alloc_pgdat_section(NODE_DATA(nodeid),
-							  size * usemap_count);
-	if (!usemap) {
-		pr_warn("%s: allocation failed\n", __func__);
-		return;
-	}
-
-	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
-		if (!present_section_nr(pnum))
-			continue;
-		usemap_map[nr_consumed_maps] = usemap;
-		usemap += size;
-		check_usemap_section_nr(nodeid, usemap_map[nr_consumed_maps]);
-		nr_consumed_maps++;
-	}
-}
-
 #ifndef CONFIG_SPARSEMEM_VMEMMAP
 struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
 		struct vmem_altmap *altmap)
@@ -418,44 +388,6 @@  struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
 					  BOOTMEM_ALLOC_ACCESSIBLE, nid);
 	return map;
 }
-void __init sparse_mem_maps_populate_node(struct page **map_map,
-					  unsigned long pnum_begin,
-					  unsigned long pnum_end,
-					  unsigned long map_count, int nodeid)
-{
-	void *map;
-	unsigned long pnum;
-	unsigned long size = sizeof(struct page) * PAGES_PER_SECTION;
-	int nr_consumed_maps;
-
-	size = PAGE_ALIGN(size);
-	map = memblock_virt_alloc_try_nid_raw(size * map_count,
-					      PAGE_SIZE, __pa(MAX_DMA_ADDRESS),
-					      BOOTMEM_ALLOC_ACCESSIBLE, nodeid);
-	if (map) {
-		nr_consumed_maps = 0;
-		for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
-			if (!present_section_nr(pnum))
-				continue;
-			map_map[nr_consumed_maps] = map;
-			map += size;
-			nr_consumed_maps++;
-		}
-		return;
-	}
-
-	/* fallback */
-	nr_consumed_maps = 0;
-	for (pnum = pnum_begin; pnum < pnum_end; pnum++) {
-		if (!present_section_nr(pnum))
-			continue;
-		map_map[nr_consumed_maps] = sparse_mem_map_populate(pnum, nodeid, NULL);
-		if (map_map[nr_consumed_maps++])
-			continue;
-		pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
-		       __func__);
-	}
-}
 
 static unsigned long section_map_size(void)
 {
@@ -495,73 +427,15 @@  struct page * __init sparse_populate_node_section(struct page *map_base,
 }
 #endif /* !CONFIG_SPARSEMEM_VMEMMAP */
 
-static void __init sparse_early_mem_maps_alloc_node(void *data,
-				 unsigned long pnum_begin,
-				 unsigned long pnum_end,
-				 unsigned long map_count, int nodeid)
-{
-	struct page **map_map = (struct page **)data;
-	sparse_mem_maps_populate_node(map_map, pnum_begin, pnum_end,
-					 map_count, nodeid);
-}
-
 void __weak __meminit vmemmap_populate_print_last(void)
 {
 }
 
-/**
- *  alloc_usemap_and_memmap - memory alloction for pageblock flags and vmemmap
- *  @map: usemap_map for pageblock flags or mmap_map for vmemmap
- *  @unit_size: size of map unit
- */
-static void __init alloc_usemap_and_memmap(void (*alloc_func)
-					(void *, unsigned long, unsigned long,
-					unsigned long, int), void *data,
-					int data_unit_size)
-{
-	unsigned long pnum;
-	unsigned long map_count;
-	int nodeid_begin = 0;
-	unsigned long pnum_begin = 0;
-
-	for_each_present_section_nr(0, pnum) {
-		struct mem_section *ms;
-
-		ms = __nr_to_section(pnum);
-		nodeid_begin = sparse_early_nid(ms);
-		pnum_begin = pnum;
-		break;
-	}
-	map_count = 1;
-	for_each_present_section_nr(pnum_begin + 1, pnum) {
-		struct mem_section *ms;
-		int nodeid;
-
-		ms = __nr_to_section(pnum);
-		nodeid = sparse_early_nid(ms);
-		if (nodeid == nodeid_begin) {
-			map_count++;
-			continue;
-		}
-		/* ok, we need to take cake of from pnum_begin to pnum - 1*/
-		alloc_func(data, pnum_begin, pnum,
-						map_count, nodeid_begin);
-		/* new start, update count etc*/
-		nodeid_begin = nodeid;
-		pnum_begin = pnum;
-		data += map_count * data_unit_size;
-		map_count = 1;
-	}
-	/* ok, last chunk */
-	alloc_func(data, pnum_begin, __highest_present_section_nr+1,
-						map_count, nodeid_begin);
-}
-
 /*
  * Initialize sparse on a specific node. The node spans [pnum_begin, pnum_end)
  * And number of present sections in this node is map_count.
  */
-void __init sparse_init_nid(int nid, unsigned long pnum_begin,
+static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 				   unsigned long pnum_end,
 				   unsigned long map_count)
 {
@@ -617,87 +491,24 @@  void __init sparse_init_nid(int nid, unsigned long pnum_begin,
  */
 void __init sparse_init(void)
 {
-	unsigned long pnum;
-	struct page *map;
-	struct page **map_map;
-	unsigned long *usemap;
-	unsigned long **usemap_map;
-	int size, size2;
-	int nr_consumed_maps = 0;
-
-	/* see include/linux/mmzone.h 'struct mem_section' definition */
-	BUILD_BUG_ON(!is_power_of_2(sizeof(struct mem_section)));
+	unsigned long pnum_begin = first_present_section_nr();
+	int nid_begin = sparse_early_nid(__nr_to_section(pnum_begin));
+	unsigned long pnum_end, map_count = 1;
 
-	/* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
-	set_pageblock_order();
+	for_each_present_section_nr(pnum_begin + 1, pnum_end) {
+		int nid = sparse_early_nid(__nr_to_section(pnum_end));
 
-	/*
-	 * map is using big page (aka 2M in x86 64 bit)
-	 * usemap is less one page (aka 24 bytes)
-	 * so alloc 2M (with 2M align) and 24 bytes in turn will
-	 * make next 2M slip to one more 2M later.
-	 * then in big system, the memory will have a lot of holes...
-	 * here try to allocate 2M pages continuously.
-	 *
-	 * powerpc need to call sparse_init_one_section right after each
-	 * sparse_early_mem_map_alloc, so allocate usemap_map at first.
-	 */
-	size = sizeof(unsigned long *) * nr_present_sections;
-	usemap_map = memblock_virt_alloc(size, 0);
-	if (!usemap_map)
-		panic("can not allocate usemap_map\n");
-	alloc_usemap_and_memmap(sparse_early_usemaps_alloc_node,
-				(void *)usemap_map,
-				sizeof(usemap_map[0]));
-
-	size2 = sizeof(struct page *) * nr_present_sections;
-	map_map = memblock_virt_alloc(size2, 0);
-	if (!map_map)
-		panic("can not allocate map_map\n");
-	alloc_usemap_and_memmap(sparse_early_mem_maps_alloc_node,
-				(void *)map_map,
-				sizeof(map_map[0]));
-
-	/* The numner of present sections stored in nr_present_sections
-	 * are kept the same since mem sections are marked as present in
-	 * memory_present(). In this for loop, we need check which sections
-	 * failed to allocate memmap or usemap, then clear its
-	 * ->section_mem_map accordingly. During this process, we need
-	 * increase 'nr_consumed_maps' whether its allocation of memmap
-	 * or usemap failed or not, so that after we handle the i-th
-	 * memory section, can get memmap and usemap of (i+1)-th section
-	 * correctly. */
-	for_each_present_section_nr(0, pnum) {
-		struct mem_section *ms;
-
-		if (nr_consumed_maps >= nr_present_sections) {
-			pr_err("nr_consumed_maps goes beyond nr_present_sections\n");
-			break;
-		}
-		ms = __nr_to_section(pnum);
-		usemap = usemap_map[nr_consumed_maps];
-		if (!usemap) {
-			ms->section_mem_map = 0;
-			nr_consumed_maps++;
-			continue;
-		}
-
-		map = map_map[nr_consumed_maps];
-		if (!map) {
-			ms->section_mem_map = 0;
-			nr_consumed_maps++;
+		if (nid == nid_begin) {
+			map_count++;
 			continue;
 		}
-
-		sparse_init_one_section(__nr_to_section(pnum), pnum, map,
-								usemap);
-		nr_consumed_maps++;
+		sparse_init_nid(nid, pnum_begin, pnum_end, map_count);
+		nid_begin = nid;
+		pnum_begin = pnum_end;
+		map_count = 1;
 	}
-
+	sparse_init_nid(nid_begin, pnum_begin, pnum_end, map_count);
 	vmemmap_populate_print_last();
-
-	memblock_free_early(__pa(map_map), size2);
-	memblock_free_early(__pa(usemap_map), size);
 }
 
 #ifdef CONFIG_MEMORY_HOTPLUG