[RFC PATCH v5 12/19] memory-hotplug: introduce new function arch_remove_memory()
From: Wen Congyang <hidden>
Date: 2012-07-27 10:27:17
Also in:
linux-acpi, linux-mm, linux-s390, linux-sh, lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), memory hot(un)plug, memory management, s390 architecture, superh, the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Madhavan Srinivasan, Michael Ellerman, David Hildenbrand, Oscar Salvador, Andrew Morton, Heiko Carstens, Vasily Gorbik, Alexander Gordeev, Yoshinori Sato, Rich Felker, John Paul Adrian Glaubitz, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
We don't call __add_pages() directly in the function add_memory() because some other architecture related things need to be done before or after calling __add_pages(). So we should introduce a new function arch_remove_memory() to revert the things done in arch_add_memory(). Note: the function for s390 is not implemented(I don't know how to implement it for s390). CC: David Rientjes <rientjes@google.com> CC: Jiang Liu <redacted> CC: Len Brown <redacted> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: Paul Mackerras <redacted> CC: Christoph Lameter <redacted> Cc: Minchan Kim <redacted> CC: Andrew Morton <akpm@linux-foundation.org> CC: KOSAKI Motohiro <redacted> CC: Yasuaki Ishimatsu <redacted> Signed-off-by: Wen Congyang <redacted> --- arch/ia64/mm/init.c | 16 ++++ arch/powerpc/mm/mem.c | 14 +++ arch/s390/mm/init.c | 8 ++ arch/sh/mm/init.c | 15 +++ arch/tile/mm/init.c | 8 ++ arch/x86/include/asm/pgtable_types.h | 1 + arch/x86/mm/init_32.c | 10 ++ arch/x86/mm/init_64.c | 160 ++++++++++++++++++++++++++++++++++ arch/x86/mm/pageattr.c | 47 +++++----- include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 1 + 11 files changed, 259 insertions(+), 22 deletions(-)
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
index 0eab454..1e345ed 100644
--- a/arch/ia64/mm/init.c
+++ b/arch/ia64/mm/init.c@@ -688,6 +688,22 @@ int arch_add_memory(int nid, u64 start, u64 size) return ret; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + int ret; + + ret = __remove_pages(start_pfn, nr_pages); + if (ret) + pr_warn("%s: Problem encountered in __remove_pages() as" + " ret=%d\n", __func__, ret); + + return ret; +} +#endif #endif /*
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index baaafde..249cef4 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c@@ -133,6 +133,20 @@ int arch_add_memory(int nid, u64 start, u64 size) return __add_pages(nid, zone, start_pfn, nr_pages); } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + + start = (unsigned long)__va(start); + if (remove_section_mapping(start, start + size)) + return -EINVAL; + + return __remove_pages(start_pfn, nr_pages); +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */ /*
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 6adbc08..ca4bc46 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c@@ -257,4 +257,12 @@ int arch_add_memory(int nid, u64 start, u64 size) vmem_remove_mapping(start, size); return rc; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + /* TODO */ + return -EBUSY; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index 82cc576..fc84491 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c@@ -558,4 +558,19 @@ int memory_add_physaddr_to_nid(u64 addr) EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid); #endif +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + int ret; + + ret = __remove_pages(start_pfn, nr_pages); + if (unlikely(ret)) + pr_warn("%s: Failed, __remove_pages() == %d\n", __func__, + ret); + + return ret; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */
diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c
index ef29d6c..2749515 100644
--- a/arch/tile/mm/init.c
+++ b/arch/tile/mm/init.c@@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size) { return -EINVAL; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + /* TODO */ + return -EBUSY; +} +#endif #endif struct kmem_cache *pgd_cache;
diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h
index 013286a..b725af2 100644
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h@@ -334,6 +334,7 @@ static inline void update_page_count(int level, unsigned long pages) { } * as a pte too. */ extern pte_t *lookup_address(unsigned long address, unsigned int *level); +extern int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase); #endif /* !__ASSEMBLY__ */
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 575d86f..a690153 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c@@ -842,6 +842,16 @@ int arch_add_memory(int nid, u64 start, u64 size) return __add_pages(nid, zone, start_pfn, nr_pages); } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(unsigned long start, unsigned long size) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + + return __remove_pages(start_pfn, nr_pages); +} +#endif #endif /*
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index 2b6b4a3..f1554a9 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c@@ -675,6 +675,166 @@ int arch_add_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(arch_add_memory); +static void __meminit +phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end) +{ + unsigned pages = 0; + int i = pte_index(addr); + + pte_t *pte = pte_page + pte_index(addr); + + for (; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE, pte++) { + + if (addr >= end) + break; + + if (!pte_present(*pte)) + continue; + + pages++; + set_pte(pte, __pte(0)); + } + + update_page_count(PG_LEVEL_4K, -pages); +} + +static void __meminit +phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pmd_index(addr); + + for (; i < PTRS_PER_PMD; i++, addr = next) { + unsigned long pte_phys; + pmd_t *pmd = pmd_page + pmd_index(addr); + pte_t *pte; + + if (addr >= end) + break; + + next = (addr & PMD_MASK) + PMD_SIZE; + + if (!pmd_present(*pmd)) + continue; + + if (pmd_large(*pmd)) { + if ((addr & ~PMD_MASK) == 0 && next <= end) { + set_pmd(pmd, __pmd(0)); + pages++; + continue; + } + + /* + * We use 2M page, but we need to remove part of them, + * so split 2M page to 4K page. + */ + pte = alloc_low_page(&pte_phys); + __split_large_page((pte_t *)pmd, addr, pte); + + spin_lock(&init_mm.page_table_lock); + pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + spin_lock(&init_mm.page_table_lock); + pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd)); + phys_pte_remove(pte, addr, end); + unmap_low_page(pte); + spin_unlock(&init_mm.page_table_lock); + } + update_page_count(PG_LEVEL_2M, -pages); +} + +static void __meminit +phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end) +{ + unsigned long pages = 0, next; + int i = pud_index(addr); + + for (; i < PTRS_PER_PUD; i++, addr = next) { + unsigned long pmd_phys; + pud_t *pud = pud_page + pud_index(addr); + pmd_t *pmd; + + if (addr >= end) + break; + + next = (addr & PUD_MASK) + PUD_SIZE; + + if (!pud_present(*pud)) + continue; + + if (pud_large(*pud)) { + if ((addr & ~PUD_MASK) == 0 && next <= end) { + set_pud(pud, __pud(0)); + pages++; + continue; + } + + /* + * We use 1G page, but we need to remove part of them, + * so split 1G page to 2M page. + */ + pmd = alloc_low_page(&pmd_phys); + __split_large_page((pte_t *)pud, addr, (pte_t *)pmd); + + spin_lock(&init_mm.page_table_lock); + pud_populate(&init_mm, pud, __va(pmd_phys)); + spin_unlock(&init_mm.page_table_lock); + } + + pmd = map_low_page(pmd_offset(pud, 0)); + phys_pmd_remove(pmd, addr, end); + unmap_low_page(pmd); + __flush_tlb_all(); + } + __flush_tlb_all(); + + update_page_count(PG_LEVEL_1G, -pages); +} + +void __meminit +kernel_physical_mapping_remove(unsigned long start, unsigned long end) +{ + unsigned long next; + + start = (unsigned long)__va(start); + end = (unsigned long)__va(end); + + for (; start < end; start = next) { + pgd_t *pgd = pgd_offset_k(start); + pud_t *pud; + + next = (start + PGDIR_SIZE) & PGDIR_MASK; + if (next > end) + next = end; + + if (!pgd_present(*pgd)) + continue; + + pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); + phys_pud_remove(pud, __pa(start), __pa(end)); + unmap_low_page(pud); + } + + __flush_tlb_all(); +} + +#ifdef CONFIG_MEMORY_HOTREMOVE +int __ref arch_remove_memory(unsigned long start, unsigned long size) +{ + unsigned long start_pfn = start >> PAGE_SHIFT; + unsigned long nr_pages = size >> PAGE_SHIFT; + int ret; + + ret = __remove_pages(start_pfn, nr_pages); + WARN_ON_ONCE(ret); + + kernel_physical_mapping_remove(start, start + size); + + return ret; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */ static struct kcore_list kcore_vsyscall;
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 931930a..c22963d 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c@@ -501,21 +501,13 @@ out_unlock: return do_split; } -static int split_large_page(pte_t *kpte, unsigned long address) +int __split_large_page(pte_t *kpte, unsigned long address, pte_t *pbase) { unsigned long pfn, pfninc = 1; unsigned int i, level; - pte_t *pbase, *tmp; + pte_t *tmp; pgprot_t ref_prot; - struct page *base; - - if (!debug_pagealloc) - spin_unlock(&cpa_lock); - base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0); - if (!debug_pagealloc) - spin_lock(&cpa_lock); - if (!base) - return -ENOMEM; + struct page *base = virt_to_page(pbase); spin_lock(&pgd_lock); /*
@@ -523,10 +515,11 @@ static int split_large_page(pte_t *kpte, unsigned long address) * up for us already: */ tmp = lookup_address(address, &level); - if (tmp != kpte) - goto out_unlock; + if (tmp != kpte) { + spin_unlock(&pgd_lock); + return 1; + } - pbase = (pte_t *)page_address(base); paravirt_alloc_pte(&init_mm, page_to_pfn(base)); ref_prot = pte_pgprot(pte_clrhuge(*kpte)); /*
@@ -579,17 +572,27 @@ static int split_large_page(pte_t *kpte, unsigned long address) * going on. */ __flush_tlb_all(); + spin_unlock(&pgd_lock); - base = NULL; + return 0; +} -out_unlock: - /* - * If we dropped out via the lookup_address check under - * pgd_lock then stick the page back into the pool: - */ - if (base) +static int split_large_page(pte_t *kpte, unsigned long address) +{ + pte_t *pbase; + struct page *base; + + if (!debug_pagealloc) + spin_unlock(&cpa_lock); + base = alloc_pages(GFP_KERNEL | __GFP_NOTRACK, 0); + if (!debug_pagealloc) + spin_lock(&cpa_lock); + if (!base) + return -ENOMEM; + + pbase = (pte_t *)page_address(base); + if (__split_large_page(kpte, address, pbase)) __free_page(base); - spin_unlock(&pgd_lock); return 0; }
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 8bf820d..0d500be 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h@@ -85,6 +85,7 @@ extern void __online_page_free(struct page *page); #ifdef CONFIG_MEMORY_HOTREMOVE extern bool is_pageblock_removable_nolock(struct page *page); +extern int arch_remove_memory(unsigned long start, unsigned long size); #endif /* CONFIG_MEMORY_HOTREMOVE */ /* reasonably generic interface to expand the physical pages in a zone */
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index a9e1579..0c932e1 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c@@ -1071,6 +1071,7 @@ int __ref remove_memory(int nid, u64 start, u64 size) /* remove memmap entry */ firmware_map_remove(start, start + size, "System RAM"); + arch_remove_memory(start, size); out: unlock_memory_hotplug(); return ret;
--
1.7.1