This is in preparation to update radix to implement vmemmap optimization for
devdax. Below are the rules w.r.t radix vmemmap mapping
1. First try to map things using PMD (2M)
2. With altmap if altmap cross-boundary check returns true, fall back to PAGE_SIZE
3. IF we can't allocate PMD_SIZE backing memory for vmemmap, fallback to PAGE_SIZE
On removing vmemmap mapping, check if every subsection that is using the vmemmap
area is invalid. If found to be invalid, that implies we can safely free the
vmemmap area. We don't use the PAGE_UNUSED pattern used by x86 because with 64K
page size, we need to do the above check even at the PAGE_SIZE granularity.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
arch/powerpc/include/asm/book3s/64/radix.h | 2 +
arch/powerpc/include/asm/pgtable.h | 3 +
arch/powerpc/mm/book3s64/radix_pgtable.c | 293 +++++++++++++++++++--
arch/powerpc/mm/init_64.c | 26 +-
4 files changed, 293 insertions(+), 31 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h
index 8cdff5a05011..87d4c1e62491 100644
--- a/arch/powerpc/include/asm/book3s/64/radix.h
+++ b/arch/powerpc/include/asm/book3s/64/radix.h
@@ -332,6 +332,8 @@ extern int __meminit radix__vmemmap_create_mapping(unsigned long start,
unsigned long phys);
int __meminit radix__vmemmap_populate(unsigned long start, unsigned long end,
int node, struct vmem_altmap *altmap);
+void __ref radix__vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap);
extern void radix__vmemmap_remove_mapping(unsigned long start,
unsigned long page_size);
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 9972626ddaf6..6d4cd2ebae6e 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -168,6 +168,9 @@ static inline bool is_ioremap_addr(const void *x)
struct seq_file;
void arch_report_meminfo(struct seq_file *m);
+int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size);
+bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
+ unsigned long page_size);
#endif /* CONFIG_PPC64 */
#endif /* __ASSEMBLY__ */
diff --git a/arch/powerpc/mm/book3s64/radix_pgtable.c b/arch/powerpc/mm/book3s64/radix_pgtable.c
index d7e2dd3d4add..65de8630abcb 100644
--- a/arch/powerpc/mm/book3s64/radix_pgtable.c
+++ b/arch/powerpc/mm/book3s64/radix_pgtable.c
@@ -742,8 +742,57 @@ static void free_pud_table(pud_t *pud_start, p4d_t *p4d)
p4d_clear(p4d);
}
+static bool __meminit vmemmap_pmd_is_unused(unsigned long addr, unsigned long end)
+{
+ unsigned long start = ALIGN_DOWN(addr, PMD_SIZE);
+
+ return vmemmap_populated(start, PMD_SIZE);
+}
+
+static bool __meminit vmemmap_page_is_unused(unsigned long addr, unsigned long end)
+{
+ unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
+
+ return vmemmap_populated(start, PAGE_SIZE);
+
+}
+
+static void __meminit free_vmemmap_pages(struct page *page,
+ struct vmem_altmap *altmap,
+ int order)
+{
+ unsigned int nr_pages = 1 << order;
+
+ if (altmap) {
+ unsigned long alt_start, alt_end;
+ unsigned long base_pfn = page_to_pfn(page);
+
+ /*
+ * with 1G vmemmap mmaping we can have things setup
+ * such that even though atlmap is specified we never
+ * used altmap.
+ */
+ alt_start = altmap->base_pfn;
+ alt_end = altmap->base_pfn + altmap->reserve +
+ altmap->free + altmap->alloc + altmap->align;
+
+ if (base_pfn >= alt_start && base_pfn < alt_end) {
+ vmem_altmap_free(altmap, nr_pages);
+ return;
+ }
+ }
+
+ if (PageReserved(page)) {
+ /* allocated from memblock */
+ while (nr_pages--)
+ free_reserved_page(page++);
+ } else
+ free_pages((unsigned long)page_address(page), order);
+}
+
static void remove_pte_table(pte_t *pte_start, unsigned long addr,
- unsigned long end, bool direct)
+ unsigned long end, bool direct,
+ struct vmem_altmap *altmap)
{
unsigned long next, pages = 0;
pte_t *pte;
@@ -757,24 +806,23 @@ static void remove_pte_table(pte_t *pte_start, unsigned long addr,
if (!pte_present(*pte))
continue;
- if (!PAGE_ALIGNED(addr) || !PAGE_ALIGNED(next)) {
- /*
- * The vmemmap_free() and remove_section_mapping()
- * codepaths call us with aligned addresses.
- */
- WARN_ONCE(1, "%s: unaligned range\n", __func__);
- continue;
+ if (PAGE_ALIGNED(addr) && PAGE_ALIGNED(next)) {
+ if (!direct)
+ free_vmemmap_pages(pte_page(*pte), altmap, 0);
+ pte_clear(&init_mm, addr, pte);
+ pages++;
+ } else if (!direct && vmemmap_page_is_unused(addr, next)) {
+ free_vmemmap_pages(pte_page(*pte), altmap, 0);
+ pte_clear(&init_mm, addr, pte);
}
-
- pte_clear(&init_mm, addr, pte);
- pages++;
}
if (direct)
update_page_count(mmu_virtual_psize, -pages);
}
static void __meminit remove_pmd_table(pmd_t *pmd_start, unsigned long addr,
- unsigned long end, bool direct)
+ unsigned long end, bool direct,
+ struct vmem_altmap *altmap)
{
unsigned long next, pages = 0;
pte_t *pte_base;
@@ -788,18 +836,21 @@ static void __meminit remove_pmd_table(pmd_t *pmd_start, unsigned long addr,
continue;
if (pmd_is_leaf(*pmd)) {
- if (!IS_ALIGNED(addr, PMD_SIZE) ||
- !IS_ALIGNED(next, PMD_SIZE)) {
- WARN_ONCE(1, "%s: unaligned range\n", __func__);
- continue;
+ if (IS_ALIGNED(addr, PMD_SIZE) &&
+ IS_ALIGNED(next, PMD_SIZE)) {
+ if (!direct)
+ free_vmemmap_pages(pmd_page(*pmd), altmap, get_order(PMD_SIZE));
+ pte_clear(&init_mm, addr, (pte_t *)pmd);
+ pages++;
+ } else if (vmemmap_pmd_is_unused(addr, next)) {
+ free_vmemmap_pages(pmd_page(*pmd), altmap, get_order(PMD_SIZE));
+ pte_clear(&init_mm, addr, (pte_t *)pmd);
}
- pte_clear(&init_mm, addr, (pte_t *)pmd);
- pages++;
continue;
}
pte_base = (pte_t *)pmd_page_vaddr(*pmd);
- remove_pte_table(pte_base, addr, next, direct);
+ remove_pte_table(pte_base, addr, next, direct, altmap);
free_pte_table(pte_base, pmd);
}
if (direct)
@@ -807,7 +858,8 @@ static void __meminit remove_pmd_table(pmd_t *pmd_start, unsigned long addr,
}
static void __meminit remove_pud_table(pud_t *pud_start, unsigned long addr,
- unsigned long end, bool direct)
+ unsigned long end, bool direct,
+ struct vmem_altmap *altmap)
{
unsigned long next, pages = 0;
pmd_t *pmd_base;
@@ -832,15 +884,16 @@ static void __meminit remove_pud_table(pud_t *pud_start, unsigned long addr,
}
pmd_base = pud_pgtable(*pud);
- remove_pmd_table(pmd_base, addr, next, direct);
+ remove_pmd_table(pmd_base, addr, next, direct, altmap);
free_pmd_table(pmd_base, pud);
}
if (direct)
update_page_count(MMU_PAGE_1G, -pages);
}
-static void __meminit remove_pagetable(unsigned long start, unsigned long end,
- bool direct)
+static void __meminit
+remove_pagetable(unsigned long start, unsigned long end, bool direct,
+ struct vmem_altmap *altmap)
{
unsigned long addr, next;
pud_t *pud_base;
@@ -869,7 +922,7 @@ static void __meminit remove_pagetable(unsigned long start, unsigned long end,
}
pud_base = p4d_pgtable(*p4d);
- remove_pud_table(pud_base, addr, next, direct);
+ remove_pud_table(pud_base, addr, next, direct, altmap);
free_pud_table(pud_base, p4d);
}
@@ -892,7 +945,7 @@ int __meminit radix__create_section_mapping(unsigned long start,
int __meminit radix__remove_section_mapping(unsigned long start, unsigned long end)
{
- remove_pagetable(start, end, true);
+ remove_pagetable(start, end, true, NULL);
return 0;
}
#endif /* CONFIG_MEMORY_HOTPLUG */
@@ -924,10 +977,198 @@ int __meminit radix__vmemmap_create_mapping(unsigned long start,
return 0;
}
+int __meminit vmemmap_check_pmd(pmd_t *pmd, int node,
+ unsigned long addr, unsigned long next)
+{
+ int large = pmd_large(*pmd);
+
+ if (pmd_large(*pmd))
+ vmemmap_verify((pte_t *)pmd, node, addr, next);
+
+ return large;
+}
+
+void __meminit vmemmap_set_pmd(pmd_t *pmdp, void *p, int node,
+ unsigned long addr, unsigned long next)
+{
+ pte_t entry;
+ pte_t *ptep = pmdp_ptep(pmdp);
+
+ entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
+ set_pte_at(&init_mm, addr, ptep, entry);
+ asm volatile("ptesync": : :"memory");
+
+ vmemmap_verify(ptep, node, addr, next);
+}
+
+static pte_t * __meminit radix__vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
+ struct vmem_altmap *altmap,
+ struct page *reuse)
+{
+ pte_t *pte = pte_offset_kernel(pmd, addr);
+
+ if (pte_none(*pte)) {
+ pte_t entry;
+ void *p;
+
+ if (!reuse) {
+ p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap);
+ if (!p)
+ return NULL;
+ } else {
+ /*
+ * When a PTE/PMD entry is freed from the init_mm
+ * there's a free_pages() call to this page allocated
+ * above. Thus this get_page() is paired with the
+ * put_page_testzero() on the freeing path.
+ * This can only called by certain ZONE_DEVICE path,
+ * and through vmemmap_populate_compound_pages() when
+ * slab is available.
+ */
+ get_page(reuse);
+ p = page_to_virt(reuse);
+ }
+ entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
+ set_pte_at(&init_mm, addr, pte, entry);
+ asm volatile("ptesync": : :"memory");
+ }
+ return pte;
+}
+
+static inline pud_t *vmemmap_pud_alloc(p4d_t *p4d, int node,
+ unsigned long address)
+{
+ pud_t *pud;
+
+ /* All early vmemmap mapping to keep simple do it at PAGE_SIZE */
+ if (unlikely(p4d_none(*p4d))) {
+ if (unlikely(!slab_is_available())) {
+ pud = early_alloc_pgtable(PAGE_SIZE, node, 0, 0);
+ p4d_populate(&init_mm, p4d, pud);
+ /* go to the pud_offset */
+ } else
+ return pud_alloc(&init_mm, p4d, address);
+ }
+ return pud_offset(p4d, address);
+}
+
+static inline pmd_t *vmemmap_pmd_alloc(pud_t *pud, int node,
+ unsigned long address)
+{
+ pmd_t *pmd;
+
+ /* All early vmemmap mapping to keep simple do it at PAGE_SIZE */
+ if (unlikely(pud_none(*pud))) {
+ if (unlikely(!slab_is_available())) {
+ pmd = early_alloc_pgtable(PAGE_SIZE, node, 0, 0);
+ pud_populate(&init_mm, pud, pmd);
+ } else
+ return pmd_alloc(&init_mm, pud, address);
+ }
+ return pmd_offset(pud, address);
+}
+
+static inline pte_t *vmemmap_pte_alloc(pmd_t *pmd, int node,
+ unsigned long address)
+{
+ pte_t *pte;
+
+ /* All early vmemmap mapping to keep simple do it at PAGE_SIZE */
+ if (unlikely(pmd_none(*pmd))) {
+ if (unlikely(!slab_is_available())) {
+ pte = early_alloc_pgtable(PAGE_SIZE, node, 0, 0);
+ pmd_populate(&init_mm, pmd, pte);
+ } else
+ return pte_alloc_kernel(pmd, address);
+ }
+ return pte_offset_kernel(pmd, address);
+}
+
+
+
+int __meminit radix__vmemmap_populate(unsigned long start, unsigned long end, int node,
+ struct vmem_altmap *altmap)
+{
+ unsigned long addr;
+ unsigned long next;
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ for (addr = start; addr < end; addr = next) {
+ next = pmd_addr_end(addr, end);
+
+ pgd = pgd_offset_k(addr);
+ p4d = p4d_offset(pgd, addr);
+ pud = vmemmap_pud_alloc(p4d, node, addr);
+ if (!pud)
+ return -ENOMEM;
+ pmd = vmemmap_pmd_alloc(pud, node, addr);
+ if (!pmd)
+ return -ENOMEM;
+ if (pmd_none(READ_ONCE(*pmd))) {
+ void *p;
+
+ if (altmap && altmap_cross_boundary(altmap, start, PMD_SIZE)) {
+ /* make sure we don't create altmap mappings covery things outside. */
+ goto base_mapping;
+
+ }
+
+ p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
+ if (p) {
+ vmemmap_set_pmd(pmd, p, node, addr, next);
+ continue;
+ } else if (altmap) {
+ /*
+ * No fallback: In any case we care about, the
+ * altmap should be reasonably sized and aligned
+ * such that vmemmap_alloc_block_buf() will always
+ * succeed. For consistency with the PTE case,
+ * return an error here as failure could indicate
+ * a configuration issue with the size of the altmap.
+ */
+ return -ENOMEM;
+ }
+ } else if (vmemmap_check_pmd(pmd, node, addr, next)) {
+ /*
+ * If a huge mapping exist due to early call to
+ * vmemmap_populate, let's try to use that.
+ */
+ continue;
+ }
+base_mapping:
+ /*
+ * Not able allocate higher order memory to back memmap
+ * or we found a pointer to pte page. Allocate base page
+ * size vmemmap
+ */
+ pte = vmemmap_pte_alloc(pmd, node, addr);
+ if (!pte)
+ return -ENOMEM;
+
+ pte = radix__vmemmap_pte_populate(pmd, addr, node, altmap, NULL);
+ if (!pte)
+ return -ENOMEM;
+
+ vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
+ next = addr + PAGE_SIZE;
+ }
+ return 0;
+}
+
#ifdef CONFIG_MEMORY_HOTPLUG
void __meminit radix__vmemmap_remove_mapping(unsigned long start, unsigned long page_size)
{
- remove_pagetable(start, start + page_size, false);
+ remove_pagetable(start, start + page_size, true, NULL);
+}
+
+void __ref radix__vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap)
+{
+ remove_pagetable(start, end, false, altmap);
}
#endif
#endif
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index fe1b83020e0d..5701faca39ef 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -92,7 +92,7 @@ static struct page * __meminit vmemmap_subsection_start(unsigned long vmemmap_ad
* a page table lookup here because with the hash translation we don't keep
* vmemmap details in linux page table.
*/
-static int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size)
+int __meminit vmemmap_populated(unsigned long vmemmap_addr, int vmemmap_map_size)
{
struct page *start;
unsigned long vmemmap_end = vmemmap_addr + vmemmap_map_size;
@@ -183,8 +183,8 @@ static __meminit int vmemmap_list_populate(unsigned long phys,
return 0;
}
-static bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
- unsigned long page_size)
+bool altmap_cross_boundary(struct vmem_altmap *altmap, unsigned long start,
+ unsigned long page_size)
{
unsigned long nr_pfn = page_size / sizeof(struct page);
unsigned long start_pfn = page_to_pfn((struct page *)start);
@@ -204,6 +204,11 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
bool altmap_alloc;
unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (radix_enabled())
+ return radix__vmemmap_populate(start, end, node, altmap);
+#endif
+
/* Align to the page size of the linear mapping. */
start = ALIGN_DOWN(start, page_size);
@@ -303,8 +308,8 @@ static unsigned long vmemmap_list_free(unsigned long start)
return vmem_back->phys;
}
-void __ref vmemmap_free(unsigned long start, unsigned long end,
- struct vmem_altmap *altmap)
+void __ref __vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap)
{
unsigned long page_size = 1 << mmu_psize_defs[mmu_vmemmap_psize].shift;
unsigned long page_order = get_order(page_size);
@@ -362,6 +367,17 @@ void __ref vmemmap_free(unsigned long start, unsigned long end,
vmemmap_remove_mapping(start, page_size);
}
}
+
+void __ref vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap)
+{
+#ifdef CONFIG_PPC_BOOK3S_64
+ if (radix_enabled())
+ return radix__vmemmap_free(start, end, altmap);
+#endif
+ return __vmemmap_free(start, end, altmap);
+}
+
#endif
void register_page_bootmem_memmap(unsigned long section_nr,
struct page *start_page, unsigned long size)
--
2.40.1
