This is a note to let you know that I've just added the patch titled sparc64: Reduce TLB flushes during hugepte changes to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sparc64-reduce-tlb-flushes-during-hugepte-changes.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Jun 20 10:48:29 PDT 2016 From: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx> Date: Wed, 30 Mar 2016 11:17:13 -0700 Subject: sparc64: Reduce TLB flushes during hugepte changes From: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx> [ Upstream commit 24e49ee3d76b70853a96520e46b8837e5eae65b2 ] During hugepage map/unmap, TSB and TLB flushes are currently issued at every PAGE_SIZE'd boundary which is unnecessary. We now issue the flush at REAL_HPAGE_SIZE boundaries only. Without this patch workloads which unmap a large hugepage backed VMA region get CPU lockups due to excessive TLB flush calls. Orabug: 22365539, 22643230, 22995196 Signed-off-by: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/sparc/include/asm/pgtable_64.h | 43 ++++++++++++++++++++++++++--------- arch/sparc/include/asm/tlbflush_64.h | 3 +- arch/sparc/mm/hugetlbpage.c | 33 ++++++++++++++++++++++---- arch/sparc/mm/init_64.c | 12 --------- arch/sparc/mm/tlb.c | 25 ++++++++++++++------ arch/sparc/mm/tsb.c | 32 +++++++++++++------------- 6 files changed, 97 insertions(+), 51 deletions(-) --- a/arch/sparc/include/asm/pgtable_64.h +++ b/arch/sparc/include/asm/pgtable_64.h @@ -375,7 +375,7 @@ static inline pgprot_t pgprot_noncached( #define pgprot_noncached pgprot_noncached #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) -static inline pte_t pte_mkhuge(pte_t pte) +static inline unsigned long __pte_huge_mask(void) { unsigned long mask; @@ -390,8 +390,19 @@ static inline pte_t pte_mkhuge(pte_t pte : "=r" (mask) : "i" (_PAGE_SZHUGE_4U), "i" (_PAGE_SZHUGE_4V)); - return __pte(pte_val(pte) | mask); + return mask; +} + +static inline pte_t pte_mkhuge(pte_t pte) +{ + return __pte(pte_val(pte) | __pte_huge_mask()); +} + +static inline bool is_hugetlb_pte(pte_t pte) +{ + return !!(pte_val(pte) & __pte_huge_mask()); } + #ifdef CONFIG_TRANSPARENT_HUGEPAGE static inline pmd_t pmd_mkhuge(pmd_t pmd) { @@ -403,6 +414,11 @@ static inline pmd_t pmd_mkhuge(pmd_t pmd return __pmd(pte_val(pte)); } #endif +#else +static inline bool is_hugetlb_pte(pte_t pte) +{ + return false; +} #endif static inline pte_t pte_mkdirty(pte_t pte) @@ -865,6 +881,19 @@ static inline unsigned long pud_pfn(pud_ void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, pte_t *ptep, pte_t orig, int fullmm); +static void maybe_tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, + pte_t *ptep, pte_t orig, int fullmm) +{ + /* It is more efficient to let flush_tlb_kernel_range() + * handle init_mm tlb flushes. + * + * SUN4V NOTE: _PAGE_VALID is the same value in both the SUN4U + * and SUN4V pte layout, so this inline test is fine. + */ + if (likely(mm != &init_mm) && pte_accessible(mm, orig)) + tlb_batch_add(mm, vaddr, ptep, orig, fullmm); +} + #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, unsigned long addr, @@ -881,15 +910,7 @@ static inline void __set_pte_at(struct m pte_t orig = *ptep; *ptep = pte; - - /* It is more efficient to let flush_tlb_kernel_range() - * handle init_mm tlb flushes. - * - * SUN4V NOTE: _PAGE_VALID is the same value in both the SUN4U - * and SUN4V pte layout, so this inline test is fine. - */ - if (likely(mm != &init_mm) && pte_accessible(mm, orig)) - tlb_batch_add(mm, addr, ptep, orig, fullmm); + maybe_tlb_batch_add(mm, addr, ptep, orig, fullmm); } #define set_pte_at(mm,addr,ptep,pte) \ --- a/arch/sparc/include/asm/tlbflush_64.h +++ b/arch/sparc/include/asm/tlbflush_64.h @@ -8,6 +8,7 @@ #define TLB_BATCH_NR 192 struct tlb_batch { + bool huge; struct mm_struct *mm; unsigned long tlb_nr; unsigned long active; @@ -16,7 +17,7 @@ struct tlb_batch { void flush_tsb_kernel_range(unsigned long start, unsigned long end); void flush_tsb_user(struct tlb_batch *tb); -void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr); +void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr, bool huge); /* TLB flush operations. */ --- a/arch/sparc/mm/hugetlbpage.c +++ b/arch/sparc/mm/hugetlbpage.c @@ -176,17 +176,31 @@ void set_huge_pte_at(struct mm_struct *m pte_t *ptep, pte_t entry) { int i; + pte_t orig[2]; + unsigned long nptes; if (!pte_present(*ptep) && pte_present(entry)) mm->context.huge_pte_count++; addr &= HPAGE_MASK; - for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) { - set_pte_at(mm, addr, ptep, entry); + + nptes = 1 << HUGETLB_PAGE_ORDER; + orig[0] = *ptep; + orig[1] = *(ptep + nptes / 2); + for (i = 0; i < nptes; i++) { + *ptep = entry; ptep++; addr += PAGE_SIZE; pte_val(entry) += PAGE_SIZE; } + + /* Issue TLB flush at REAL_HPAGE_SIZE boundaries */ + addr -= REAL_HPAGE_SIZE; + ptep -= nptes / 2; + maybe_tlb_batch_add(mm, addr, ptep, orig[1], 0); + addr -= REAL_HPAGE_SIZE; + ptep -= nptes / 2; + maybe_tlb_batch_add(mm, addr, ptep, orig[0], 0); } pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr, @@ -194,19 +208,28 @@ pte_t huge_ptep_get_and_clear(struct mm_ { pte_t entry; int i; + unsigned long nptes; entry = *ptep; if (pte_present(entry)) mm->context.huge_pte_count--; addr &= HPAGE_MASK; - - for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) { - pte_clear(mm, addr, ptep); + nptes = 1 << HUGETLB_PAGE_ORDER; + for (i = 0; i < nptes; i++) { + *ptep = __pte(0UL); addr += PAGE_SIZE; ptep++; } + /* Issue TLB flush at REAL_HPAGE_SIZE boundaries */ + addr -= REAL_HPAGE_SIZE; + ptep -= nptes / 2; + maybe_tlb_batch_add(mm, addr, ptep, entry, 0); + addr -= REAL_HPAGE_SIZE; + ptep -= nptes / 2; + maybe_tlb_batch_add(mm, addr, ptep, entry, 0); + return entry; } --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -324,18 +324,6 @@ static void __update_mmu_tsb_insert(stru tsb_insert(tsb, tag, tte); } -#if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) -static inline bool is_hugetlb_pte(pte_t pte) -{ - if ((tlb_type == hypervisor && - (pte_val(pte) & _PAGE_SZALL_4V) == _PAGE_SZHUGE_4V) || - (tlb_type != hypervisor && - (pte_val(pte) & _PAGE_SZALL_4U) == _PAGE_SZHUGE_4U)) - return true; - return false; -} -#endif - void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) { struct mm_struct *mm; --- a/arch/sparc/mm/tlb.c +++ b/arch/sparc/mm/tlb.c @@ -67,7 +67,7 @@ void arch_leave_lazy_mmu_mode(void) } static void tlb_batch_add_one(struct mm_struct *mm, unsigned long vaddr, - bool exec) + bool exec, bool huge) { struct tlb_batch *tb = &get_cpu_var(tlb_batch); unsigned long nr; @@ -84,13 +84,21 @@ static void tlb_batch_add_one(struct mm_ } if (!tb->active) { - flush_tsb_user_page(mm, vaddr); + flush_tsb_user_page(mm, vaddr, huge); global_flush_tlb_page(mm, vaddr); goto out; } - if (nr == 0) + if (nr == 0) { tb->mm = mm; + tb->huge = huge; + } + + if (tb->huge != huge) { + flush_tlb_pending(); + tb->huge = huge; + nr = 0; + } tb->vaddrs[nr] = vaddr; tb->tlb_nr = ++nr; @@ -104,6 +112,8 @@ out: void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr, pte_t *ptep, pte_t orig, int fullmm) { + bool huge = is_hugetlb_pte(orig); + if (tlb_type != hypervisor && pte_dirty(orig)) { unsigned long paddr, pfn = pte_pfn(orig); @@ -129,7 +139,7 @@ void tlb_batch_add(struct mm_struct *mm, no_cache_flush: if (!fullmm) - tlb_batch_add_one(mm, vaddr, pte_exec(orig)); + tlb_batch_add_one(mm, vaddr, pte_exec(orig), huge); } #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -145,7 +155,7 @@ static void tlb_batch_pmd_scan(struct mm if (pte_val(*pte) & _PAGE_VALID) { bool exec = pte_exec(*pte); - tlb_batch_add_one(mm, vaddr, exec); + tlb_batch_add_one(mm, vaddr, exec, false); } pte++; vaddr += PAGE_SIZE; @@ -185,8 +195,9 @@ void set_pmd_at(struct mm_struct *mm, un pte_t orig_pte = __pte(pmd_val(orig)); bool exec = pte_exec(orig_pte); - tlb_batch_add_one(mm, addr, exec); - tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec); + tlb_batch_add_one(mm, addr, exec, true); + tlb_batch_add_one(mm, addr + REAL_HPAGE_SIZE, exec, + true); } else { tlb_batch_pmd_scan(mm, addr, orig); } --- a/arch/sparc/mm/tsb.c +++ b/arch/sparc/mm/tsb.c @@ -76,14 +76,15 @@ void flush_tsb_user(struct tlb_batch *tb spin_lock_irqsave(&mm->context.lock, flags); - base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb; - nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries; - if (tlb_type == cheetah_plus || tlb_type == hypervisor) - base = __pa(base); - __flush_tsb_one(tb, PAGE_SHIFT, base, nentries); - + if (!tb->huge) { + base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb; + nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries; + if (tlb_type == cheetah_plus || tlb_type == hypervisor) + base = __pa(base); + __flush_tsb_one(tb, PAGE_SHIFT, base, nentries); + } #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) - if (mm->context.tsb_block[MM_TSB_HUGE].tsb) { + if (tb->huge && mm->context.tsb_block[MM_TSB_HUGE].tsb) { base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb; nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries; if (tlb_type == cheetah_plus || tlb_type == hypervisor) @@ -94,20 +95,21 @@ void flush_tsb_user(struct tlb_batch *tb spin_unlock_irqrestore(&mm->context.lock, flags); } -void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr) +void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr, bool huge) { unsigned long nentries, base, flags; spin_lock_irqsave(&mm->context.lock, flags); - base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb; - nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries; - if (tlb_type == cheetah_plus || tlb_type == hypervisor) - base = __pa(base); - __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT, nentries); - + if (!huge) { + base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb; + nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries; + if (tlb_type == cheetah_plus || tlb_type == hypervisor) + base = __pa(base); + __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT, nentries); + } #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE) - if (mm->context.tsb_block[MM_TSB_HUGE].tsb) { + if (huge && mm->context.tsb_block[MM_TSB_HUGE].tsb) { base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb; nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries; if (tlb_type == cheetah_plus || tlb_type == hypervisor) Patches currently in stable-queue which might be from nitin.m.gupta@xxxxxxxxxx are queue-4.4/sparc64-reduce-tlb-flushes-during-hugepte-changes.patch queue-4.4/sparc64-fix-numa-node-distance-initialization.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html