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(a)suse.com>
Cc: David Hildenbrand <david(a)redhat.com>
Cc: Logan Gunthorpe <logang(a)deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams(a)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 */
--
Oscar Salvador
SUSE L3