Hi Congyang, I think we should also free pages which are used by page tables after removing page tables of the memory.
From: Jianguo Wu <wujian...@huawei.com> Signed-off-by: Jianguo Wu <wujian...@huawei.com> Signed-off-by: Jiang Liu <jiang....@huawei.com> --- arch/x86/mm/init_64.c | 110 +++++++++++++++++++++++++++++++++++++++--------- 1 files changed, 89 insertions(+), 21 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 5596dfa..81f9c3b 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -675,6 +675,74 @@ int arch_add_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(arch_add_memory); +static inline void free_pagetable(struct page *page) +{ + struct zone *zone; + + __ClearPageReserved(page); + __free_page(page); + + zone = page_zone(page); + zone_span_writelock(zone); + zone->present_pages++; + zone_span_writeunlock(zone); + totalram_pages++; +} + +static void free_pte_table(pte_t *pte_start, pmd_t *pmd) +{ + pte_t *pte; + int i; + + for (i = 0; i < PTRS_PER_PTE; i++) { + pte = pte_start + i; + if (pte_val(*pte)) + break; + } + + /* free a pte talbe */ + if (i == PTRS_PER_PTE) { + free_pagetable(pmd_page(*pmd)); + pmd_clear(pmd); + } +} + +static void free_pmd_table(pmd_t *pmd_start, pud_t *pud) +{ + pmd_t *pmd; + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) { + pmd = pmd_start + i; + if (pmd_val(*pmd)) + break; + } + + /* free a pmd talbe */ + if (i == PTRS_PER_PMD) { + free_pagetable(pud_page(*pud)); + pud_clear(pud); + } +} + +static void free_pud_table(pud_t *pud_start, pgd_t *pgd) +{ + pud_t *pud; + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) { + pud = pud_start + i; + if (pud_val(*pud)) + break; + } + + /* free a pud table */ + if (i == PTRS_PER_PUD) { + free_pagetable(pgd_page(*pgd)); + pgd_clear(pgd); + } +} + static void __meminit phys_pte_remove(pte_t *pte_page, unsigned long addr, unsigned long end) { @@ -704,21 +772,19 @@ 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) { + for (; i < PTRS_PER_PMD && addr < end; 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; + next = pmd_addr_end(addr, end); if (!pmd_present(*pmd)) continue; if (pmd_large(*pmd)) { - if ((addr & ~PMD_MASK) == 0 && next <= end) { + if (IS_ALIGNED(addr, PMD_SIZE) && + IS_ALIGNED(next, PMD_SIZE)) { set_pmd(pmd, __pmd(0)); pages++; continue; @@ -729,7 +795,8 @@ phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) * so split 2M page to 4K page. */ pte = alloc_low_page(&pte_phys); - __split_large_page((pte_t *)pmd, addr, pte); + __split_large_page((pte_t *)pmd, + (unsigned long)__va(addr), pte); spin_lock(&init_mm.page_table_lock); pmd_populate_kernel(&init_mm, pmd, __va(pte_phys)); @@ -738,7 +805,8 @@ phys_pmd_remove(pmd_t *pmd_page, unsigned long addr, unsigned long end) spin_lock(&init_mm.page_table_lock); pte = map_low_page((pte_t *)pmd_page_vaddr(*pmd)); - phys_pte_remove(pte, addr, end); + phys_pte_remove(pte, addr, next); + free_pte_table(pte, pmd); unmap_low_page(pte); spin_unlock(&init_mm.page_table_lock); } @@ -751,21 +819,19 @@ 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) { + for (; i < PTRS_PER_PUD && addr < end; 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; + next = pud_addr_end(addr, end); if (!pud_present(*pud)) continue; if (pud_large(*pud)) { - if ((addr & ~PUD_MASK) == 0 && next <= end) { + if (IS_ALIGNED(addr, PUD_SIZE) && + IS_ALIGNED(next, PUD_SIZE)) { set_pud(pud, __pud(0)); pages++; continue; @@ -776,15 +842,18 @@ phys_pud_remove(pud_t *pud_page, unsigned long addr, unsigned long end) * so split 1G page to 2M page. */ pmd = alloc_low_page(&pmd_phys); - __split_large_page((pte_t *)pud, addr, (pte_t *)pmd); + __split_large_page((pte_t *)pud, + (unsigned long)__va(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); + pmd = map_low_page((pmd_t *)pud_page_vaddr(*pud)); + phys_pmd_remove(pmd, addr, next); + free_pmd_table(pmd, pud); unmap_low_page(pmd); __flush_tlb_all(); } @@ -805,15 +874,14 @@ kernel_physical_mapping_remove(unsigned long start, unsigned long end) pgd_t *pgd = pgd_offset_k(start); pud_t *pud; - next = (start + PGDIR_SIZE) & PGDIR_MASK; - if (next > end) - next = end; + next = pgd_addr_end(start, end); if (!pgd_present(*pgd)) continue; pud = map_low_page((pud_t *)pgd_page_vaddr(*pgd)); - phys_pud_remove(pud, __pa(start), __pa(end)); + phys_pud_remove(pud, __pa(start), __pa(next)); + free_pud_table(pud, pgd); unmap_low_page(pud); } -- 1.7.6.1 . On 2012-10-5 10:36, Yasuaki Ishimatsu wrote: > From: Wen Congyang <we...@cn.fujitsu.com> > > For hot removing memory, we sholud remove page table about the memory. > So the patch searches a page table about the removed memory, and clear > page table. > > CC: David Rientjes <rient...@google.com> > CC: Jiang Liu <liu...@gmail.com> > CC: Len Brown <len.br...@intel.com> > CC: Christoph Lameter <c...@linux.com> > Cc: Minchan Kim <minchan....@gmail.com> > CC: Andrew Morton <a...@linux-foundation.org> > CC: KOSAKI Motohiro <kosaki.motoh...@jp.fujitsu.com> > CC: Yasuaki Ishimatsu <isimatu.yasu...@jp.fujitsu.com> > Signed-off-by: Wen Congyang <we...@cn.fujitsu.com> > --- > arch/x86/include/asm/pgtable_types.h | 1 > arch/x86/mm/init_64.c | 147 > +++++++++++++++++++++++++++++++++++ > arch/x86/mm/pageattr.c | 47 +++++------ > 3 files changed, 173 insertions(+), 22 deletions(-) > > Index: linux-3.6/arch/x86/mm/init_64.c > =================================================================== > --- linux-3.6.orig/arch/x86/mm/init_64.c 2012-10-04 18:30:21.171698416 > +0900 > +++ linux-3.6/arch/x86/mm/init_64.c 2012-10-04 18:30:27.317704652 +0900 > @@ -675,6 +675,151 @@ int arch_add_memory(int nid, u64 start, > } > 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(u64 start, u64 size) > { > @@ -687,6 +832,8 @@ int __ref arch_remove_memory(u64 start, > ret = __remove_pages(zone, start_pfn, nr_pages); > WARN_ON_ONCE(ret); > > + kernel_physical_mapping_remove(start, start + size); > + > return ret; > } > #endif > Index: linux-3.6/arch/x86/include/asm/pgtable_types.h > =================================================================== > --- linux-3.6.orig/arch/x86/include/asm/pgtable_types.h 2012-10-04 > 18:26:51.925486954 +0900 > +++ linux-3.6/arch/x86/include/asm/pgtable_types.h 2012-10-04 > 18:30:27.322704656 +0900 > @@ -334,6 +334,7 @@ static inline void update_page_count(int > * 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__ */ > > Index: linux-3.6/arch/x86/mm/pageattr.c > =================================================================== > --- linux-3.6.orig/arch/x86/mm/pageattr.c 2012-10-04 18:26:51.923486952 > +0900 > +++ linux-3.6/arch/x86/mm/pageattr.c 2012-10-04 18:30:27.328704662 +0900 > @@ -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, > * 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, > * 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; > } > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majord...@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"d...@kvack.org"> em...@kvack.org </a> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/