[v7,05/12] mm/sparsemem: Convert kmalloc_section_memmap() to populate_section_memmap()
diff mbox series

Message ID 155677654842.2336373.17000900051843592636.stgit@dwillia2-desk3.amr.corp.intel.com
State New
Headers show
Series
  • mm: Sub-section memory hotplug support
Related show

Commit Message

Dan Williams May 2, 2019, 5:55 a.m. UTC
Allow sub-section sized ranges to be added to the memmap.
populate_section_memmap() takes an explict pfn range rather than
assuming a full section, and those parameters are plumbed all the way
through to vmmemap_populate(). There should be no sub-section usage in
current deployments. New warnings are added to clarify which memmap
allocation paths are sub-section capable.

Cc: Michal Hocko <mhocko@suse.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/mm/init_64.c |    4 ++-
 include/linux/mm.h    |    4 ++-
 mm/sparse-vmemmap.c   |   21 +++++++++++------
 mm/sparse.c           |   61 +++++++++++++++++++++++++++++++------------------
 4 files changed, 57 insertions(+), 33 deletions(-)

Comments

Oscar Salvador May 3, 2019, 8:46 a.m. UTC | #1
On Wed, May 01, 2019 at 10:55:48PM -0700, Dan Williams wrote:
> Allow sub-section sized ranges to be added to the memmap.
> populate_section_memmap() takes an explict pfn range rather than
> assuming a full section, and those parameters are plumbed all the way
> through to vmmemap_populate(). There should be no sub-section usage in
> current deployments. New warnings are added to clarify which memmap
> allocation paths are sub-section capable.
> 
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Logan Gunthorpe <logang@deltatee.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  arch/x86/mm/init_64.c |    4 ++-
>  include/linux/mm.h    |    4 ++-
>  mm/sparse-vmemmap.c   |   21 +++++++++++------
>  mm/sparse.c           |   61 +++++++++++++++++++++++++++++++------------------
>  4 files changed, 57 insertions(+), 33 deletions(-)
> 
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 20d14254b686..bb018d09d2dc 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -1457,7 +1457,9 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
>  {
>  	int err;
>  
> -	if (boot_cpu_has(X86_FEATURE_PSE))
> +	if (end - start < PAGES_PER_SECTION * sizeof(struct page))
maybe just:

	if (PHYS_PFN(end) - PHYS_PFN(start) < PAGES_PER_SECTION) ?
> +		err = vmemmap_populate_basepages(start, end, node);
> +	else if (boot_cpu_has(X86_FEATURE_PSE))
>  		err = vmemmap_populate_hugepages(start, end, node, altmap);
>  	else if (altmap) {
>  		pr_err_once("%s: no cpu support for altmap allocations\n",

Although the following looks more clear to me:

int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
                struct vmem_altmap *altmap)
{
        int err;
        bool partial_section = (PHYS_PFN(end) - PFN_PHYS(start)) < PAGES_PER_SECTION;

        if (partial_section || !boot_cpu_has(X86_FEATURE_PSE))
                err = vmemmap_populate_basepages(start, end, node);
        else if (boot_cpu_has(X86_FEATURE_PSE))
                err = vmemmap_populate_hugepages(start, end, node, altmap);
        else if (altmap) {
                pr_err_once("%s: no cpu support for altmap allocations\n",
                                __func__);
                err = -ENOMEM;
        }

        if (!err)
                sync_global_pgds(start, end - 1);
        return err;
}

> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 0e8834ac32b7..5360a0e4051d 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2748,8 +2748,8 @@ const char * arch_vma_name(struct vm_area_struct *vma);
>  void print_vma_addr(char *prefix, unsigned long rip);
>  
>  void *sparse_buffer_alloc(unsigned long size);
> -struct page *sparse_mem_map_populate(unsigned long pnum, int nid,
> -		struct vmem_altmap *altmap);
> +struct page * __populate_section_memmap(unsigned long pfn,
> +		unsigned long nr_pages, int nid, struct vmem_altmap *altmap);
>  pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
>  p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
>  pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
> index 7fec05796796..dcb023aa23d1 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -245,19 +245,26 @@ int __meminit vmemmap_populate_basepages(unsigned long start,
>  	return 0;
>  }
>  
> -struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid,
> -		struct vmem_altmap *altmap)
> +struct page * __meminit __populate_section_memmap(unsigned long pfn,
> +		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
>  	unsigned long start;
>  	unsigned long end;
> -	struct page *map;
>  
> -	map = pfn_to_page(pnum * PAGES_PER_SECTION);
> -	start = (unsigned long)map;
> -	end = (unsigned long)(map + PAGES_PER_SECTION);
> +	/*
> +	 * The minimum granularity of memmap extensions is
> +	 * SECTION_ACTIVE_SIZE as allocations are tracked in the
> +	 * 'map_active' bitmap of the section.
> +	 */
> +	end = ALIGN(pfn + nr_pages, PHYS_PFN(SECTION_ACTIVE_SIZE));

I would use PAGES_PER_SUB_SECTION directly:

	 end = ALIGN(pfn + nr_pages, PAGES_PER_SUB_SECTION);

> +	pfn &= PHYS_PFN(SECTION_ACTIVE_MASK);

	pfn &= PAGE_SUB_SECTION_MASK ?

[...]
> -static struct page *__kmalloc_section_memmap(void)
> +struct page *populate_section_memmap(unsigned long pfn,
> +		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
>  	struct page *page, *ret;
>  	unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
>  
> +	if ((pfn & ~PAGE_SECTION_MASK) || nr_pages != PAGES_PER_SECTION) {
> +		WARN(1, "%s: called with section unaligned parameters\n",
> +				__func__);
> +		return NULL;
> +	}

Can this actually happen? We need CONFIG_SPARSEMEM_VMEMMAP in order to use nvdimm,
right?

But I guess it is fine to have a safety net just in case.

> +
>  	page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
>  	if (page)
>  		goto got_map_page;
> @@ -682,15 +692,17 @@ static struct page *__kmalloc_section_memmap(void)
>  	return ret;
>  }
>  
> -static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
> +static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
>  		struct vmem_altmap *altmap)
>  {
> -	return __kmalloc_section_memmap();
> -}
> +	struct page *memmap = pfn_to_page(pfn);
> +
> +	if ((pfn & ~PAGE_SECTION_MASK) || nr_pages != PAGES_PER_SECTION) {
> +		WARN(1, "%s: called with section unaligned parameters\n",
> +				__func__);
> +		return;
> +	}
>  
> -static void __kfree_section_memmap(struct page *memmap,
> -		struct vmem_altmap *altmap)
> -{
>  	if (is_vmalloc_addr(memmap))
>  		vfree(memmap);
>  	else
> @@ -761,12 +773,13 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
>  	if (ret < 0 && ret != -EEXIST)
>  		return ret;
>  	ret = 0;
> -	memmap = kmalloc_section_memmap(section_nr, nid, altmap);
> +	memmap = populate_section_memmap(start_pfn, PAGES_PER_SECTION, nid,
> +			altmap);
>  	if (!memmap)
>  		return -ENOMEM;
>  	usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
>  	if (!usage) {
> -		__kfree_section_memmap(memmap, altmap);
> +		depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
>  		return -ENOMEM;
>  	}
>  
> @@ -788,7 +801,7 @@ int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
>  out:
>  	if (ret < 0) {
>  		kfree(usage);
> -		__kfree_section_memmap(memmap, altmap);
> +		depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
>  	}
>  	return ret;
>  }
> @@ -825,7 +838,8 @@ static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
>  #endif
>  
>  static void free_section_usage(struct page *memmap,
> -		struct mem_section_usage *usage, struct vmem_altmap *altmap)
> +		struct mem_section_usage *usage, unsigned long pfn,
> +		unsigned long nr_pages, struct vmem_altmap *altmap)
>  {
>  	struct page *usage_page;
>  
> @@ -839,7 +853,7 @@ static void free_section_usage(struct page *memmap,
>  	if (PageSlab(usage_page) || PageCompound(usage_page)) {
>  		kfree(usage);
>  		if (memmap)
> -			__kfree_section_memmap(memmap, altmap);
> +			depopulate_section_memmap(pfn, nr_pages, altmap);
>  		return;
>  	}
>  
> @@ -868,7 +882,8 @@ void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
>  
>  	clear_hwpoisoned_pages(memmap + map_offset,
>  			PAGES_PER_SECTION - map_offset);
> -	free_section_usage(memmap, usage, altmap);
> +	free_section_usage(memmap, usage, section_nr_to_pfn(__section_nr(ms)),
> +			PAGES_PER_SECTION, altmap);
>  }
>  #endif /* CONFIG_MEMORY_HOTREMOVE */
>  #endif /* CONFIG_MEMORY_HOTPLUG */
>

Patch
diff mbox series

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 20d14254b686..bb018d09d2dc 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1457,7 +1457,9 @@  int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
 {
 	int err;
 
-	if (boot_cpu_has(X86_FEATURE_PSE))
+	if (end - start < PAGES_PER_SECTION * sizeof(struct page))
+		err = vmemmap_populate_basepages(start, end, node);
+	else if (boot_cpu_has(X86_FEATURE_PSE))
 		err = vmemmap_populate_hugepages(start, end, node, altmap);
 	else if (altmap) {
 		pr_err_once("%s: no cpu support for altmap allocations\n",
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0e8834ac32b7..5360a0e4051d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2748,8 +2748,8 @@  const char * arch_vma_name(struct vm_area_struct *vma);
 void print_vma_addr(char *prefix, unsigned long rip);
 
 void *sparse_buffer_alloc(unsigned long size);
-struct page *sparse_mem_map_populate(unsigned long pnum, int nid,
-		struct vmem_altmap *altmap);
+struct page * __populate_section_memmap(unsigned long pfn,
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap);
 pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
 p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
 pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index 7fec05796796..dcb023aa23d1 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -245,19 +245,26 @@  int __meminit vmemmap_populate_basepages(unsigned long start,
 	return 0;
 }
 
-struct page * __meminit sparse_mem_map_populate(unsigned long pnum, int nid,
-		struct vmem_altmap *altmap)
+struct page * __meminit __populate_section_memmap(unsigned long pfn,
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	unsigned long start;
 	unsigned long end;
-	struct page *map;
 
-	map = pfn_to_page(pnum * PAGES_PER_SECTION);
-	start = (unsigned long)map;
-	end = (unsigned long)(map + PAGES_PER_SECTION);
+	/*
+	 * The minimum granularity of memmap extensions is
+	 * SECTION_ACTIVE_SIZE as allocations are tracked in the
+	 * 'map_active' bitmap of the section.
+	 */
+	end = ALIGN(pfn + nr_pages, PHYS_PFN(SECTION_ACTIVE_SIZE));
+	pfn &= PHYS_PFN(SECTION_ACTIVE_MASK);
+	nr_pages = end - pfn;
+
+	start = (unsigned long) pfn_to_page(pfn);
+	end = start + nr_pages * sizeof(struct page);
 
 	if (vmemmap_populate(start, end, nid, altmap))
 		return NULL;
 
-	return map;
+	return pfn_to_page(pfn);
 }
diff --git a/mm/sparse.c b/mm/sparse.c
index 8d4f28e2c25e..ed26761327bf 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -452,8 +452,8 @@  static unsigned long __init section_map_size(void)
 	return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 }
 
-struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid,
-		struct vmem_altmap *altmap)
+struct page __init *__populate_section_memmap(unsigned long pfn,
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	unsigned long size = section_map_size();
 	struct page *map = sparse_buffer_alloc(size);
@@ -534,10 +534,13 @@  static void __init sparse_init_nid(int nid, unsigned long pnum_begin,
 	}
 	sparse_buffer_init(map_count * section_map_size(), nid);
 	for_each_present_section_nr(pnum_begin, pnum) {
+		unsigned long pfn = section_nr_to_pfn(pnum);
+
 		if (pnum >= pnum_end)
 			break;
 
-		map = sparse_mem_map_populate(pnum, nid, NULL);
+		map = __populate_section_memmap(pfn, PAGES_PER_SECTION,
+				nid, NULL);
 		if (!map) {
 			pr_err("%s: node[%d] memory map backing failed. Some memory will not be available.",
 			       __func__, nid);
@@ -637,17 +640,17 @@  void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 #endif
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
-		struct vmem_altmap *altmap)
+static struct page *populate_section_memmap(unsigned long pfn,
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
-	/* This will make the necessary allocations eventually. */
-	return sparse_mem_map_populate(pnum, nid, altmap);
+	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
 }
-static void __kfree_section_memmap(struct page *memmap,
+
+static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 		struct vmem_altmap *altmap)
 {
-	unsigned long start = (unsigned long)memmap;
-	unsigned long end = (unsigned long)(memmap + PAGES_PER_SECTION);
+	unsigned long start = (unsigned long) pfn_to_page(pfn);
+	unsigned long end = start + nr_pages * sizeof(struct page);
 
 	vmemmap_free(start, end, altmap);
 }
@@ -661,11 +664,18 @@  static void free_map_bootmem(struct page *memmap)
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 #else
-static struct page *__kmalloc_section_memmap(void)
+struct page *populate_section_memmap(unsigned long pfn,
+		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	struct page *page, *ret;
 	unsigned long memmap_size = sizeof(struct page) * PAGES_PER_SECTION;
 
+	if ((pfn & ~PAGE_SECTION_MASK) || nr_pages != PAGES_PER_SECTION) {
+		WARN(1, "%s: called with section unaligned parameters\n",
+				__func__);
+		return NULL;
+	}
+
 	page = alloc_pages(GFP_KERNEL|__GFP_NOWARN, get_order(memmap_size));
 	if (page)
 		goto got_map_page;
@@ -682,15 +692,17 @@  static struct page *__kmalloc_section_memmap(void)
 	return ret;
 }
 
-static inline struct page *kmalloc_section_memmap(unsigned long pnum, int nid,
+static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages,
 		struct vmem_altmap *altmap)
 {
-	return __kmalloc_section_memmap();
-}
+	struct page *memmap = pfn_to_page(pfn);
+
+	if ((pfn & ~PAGE_SECTION_MASK) || nr_pages != PAGES_PER_SECTION) {
+		WARN(1, "%s: called with section unaligned parameters\n",
+				__func__);
+		return;
+	}
 
-static void __kfree_section_memmap(struct page *memmap,
-		struct vmem_altmap *altmap)
-{
 	if (is_vmalloc_addr(memmap))
 		vfree(memmap);
 	else
@@ -761,12 +773,13 @@  int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
 	if (ret < 0 && ret != -EEXIST)
 		return ret;
 	ret = 0;
-	memmap = kmalloc_section_memmap(section_nr, nid, altmap);
+	memmap = populate_section_memmap(start_pfn, PAGES_PER_SECTION, nid,
+			altmap);
 	if (!memmap)
 		return -ENOMEM;
 	usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);
 	if (!usage) {
-		__kfree_section_memmap(memmap, altmap);
+		depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
 		return -ENOMEM;
 	}
 
@@ -788,7 +801,7 @@  int __meminit sparse_add_one_section(int nid, unsigned long start_pfn,
 out:
 	if (ret < 0) {
 		kfree(usage);
-		__kfree_section_memmap(memmap, altmap);
+		depopulate_section_memmap(start_pfn, PAGES_PER_SECTION, altmap);
 	}
 	return ret;
 }
@@ -825,7 +838,8 @@  static inline void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
 #endif
 
 static void free_section_usage(struct page *memmap,
-		struct mem_section_usage *usage, struct vmem_altmap *altmap)
+		struct mem_section_usage *usage, unsigned long pfn,
+		unsigned long nr_pages, struct vmem_altmap *altmap)
 {
 	struct page *usage_page;
 
@@ -839,7 +853,7 @@  static void free_section_usage(struct page *memmap,
 	if (PageSlab(usage_page) || PageCompound(usage_page)) {
 		kfree(usage);
 		if (memmap)
-			__kfree_section_memmap(memmap, altmap);
+			depopulate_section_memmap(pfn, nr_pages, altmap);
 		return;
 	}
 
@@ -868,7 +882,8 @@  void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
 
 	clear_hwpoisoned_pages(memmap + map_offset,
 			PAGES_PER_SECTION - map_offset);
-	free_section_usage(memmap, usage, altmap);
+	free_section_usage(memmap, usage, section_nr_to_pfn(__section_nr(ms)),
+			PAGES_PER_SECTION, altmap);
 }
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 #endif /* CONFIG_MEMORY_HOTPLUG */