From e3ebcf64381188a2744a9829a4eb5c2b60f1974c Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Mon, 8 Oct 2012 16:30:07 -0700 Subject: thp: remove assumptions on pgtable_t type The thp page table pre-allocation code currently assumes that pgtable_t is of type "struct page *". This may not be true for all architectures, so this patch removes that assumption by replacing the functions prepare_pmd_huge_pte() and get_pmd_huge_pte() with two new functions that can be defined architecture-specific. It also removes two VM_BUG_ON checks for page_count() and page_mapcount() operating on a pgtable_t. Apart from the VM_BUG_ON removal, there will be no functional change introduced by this patch. Signed-off-by: Gerald Schaefer Cc: Andrea Arcangeli Cc: Andi Kleen Cc: Hugh Dickins Cc: Hillf Danton Cc: Martin Schwidefsky Cc: Heiko Carstens Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/huge_memory.c | 50 ++++++++------------------------------------------ 1 file changed, 8 insertions(+), 42 deletions(-) (limited to 'mm/huge_memory.c') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e19cc426c522..9ea6d1953765 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -598,19 +598,6 @@ out: } __setup("transparent_hugepage=", setup_transparent_hugepage); -static void prepare_pmd_huge_pte(pgtable_t pgtable, - struct mm_struct *mm) -{ - assert_spin_locked(&mm->page_table_lock); - - /* FIFO */ - if (!mm->pmd_huge_pte) - INIT_LIST_HEAD(&pgtable->lru); - else - list_add(&pgtable->lru, &mm->pmd_huge_pte->lru); - mm->pmd_huge_pte = pgtable; -} - static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) { if (likely(vma->vm_flags & VM_WRITE)) @@ -652,7 +639,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, */ page_add_new_anon_rmap(page, vma, haddr); set_pmd_at(mm, haddr, pmd, entry); - prepare_pmd_huge_pte(pgtable, mm); + pgtable_trans_huge_deposit(mm, pgtable); add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); mm->nr_ptes++; spin_unlock(&mm->page_table_lock); @@ -778,7 +765,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmdp_set_wrprotect(src_mm, addr, src_pmd); pmd = pmd_mkold(pmd_wrprotect(pmd)); set_pmd_at(dst_mm, addr, dst_pmd, pmd); - prepare_pmd_huge_pte(pgtable, dst_mm); + pgtable_trans_huge_deposit(dst_mm, pgtable); dst_mm->nr_ptes++; ret = 0; @@ -789,25 +776,6 @@ out: return ret; } -/* no "address" argument so destroys page coloring of some arch */ -pgtable_t get_pmd_huge_pte(struct mm_struct *mm) -{ - pgtable_t pgtable; - - assert_spin_locked(&mm->page_table_lock); - - /* FIFO */ - pgtable = mm->pmd_huge_pte; - if (list_empty(&pgtable->lru)) - mm->pmd_huge_pte = NULL; - else { - mm->pmd_huge_pte = list_entry(pgtable->lru.next, - struct page, lru); - list_del(&pgtable->lru); - } - return pgtable; -} - static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, @@ -863,7 +831,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, pmdp_clear_flush_notify(vma, haddr, pmd); /* leave pmd empty until pte is filled */ - pgtable = get_pmd_huge_pte(mm); + pgtable = pgtable_trans_huge_withdraw(mm); pmd_populate(mm, &_pmd, pgtable); for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { @@ -1028,7 +996,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, if (__pmd_trans_huge_lock(pmd, vma) == 1) { struct page *page; pgtable_t pgtable; - pgtable = get_pmd_huge_pte(tlb->mm); + pgtable = pgtable_trans_huge_withdraw(tlb->mm); page = pmd_page(*pmd); pmd_clear(pmd); tlb_remove_pmd_tlb_entry(tlb, pmd, addr); @@ -1345,11 +1313,11 @@ static int __split_huge_page_map(struct page *page, pmd = page_check_address_pmd(page, mm, address, PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); if (pmd) { - pgtable = get_pmd_huge_pte(mm); + pgtable = pgtable_trans_huge_withdraw(mm); pmd_populate(mm, &_pmd, pgtable); - for (i = 0, haddr = address; i < HPAGE_PMD_NR; - i++, haddr += PAGE_SIZE) { + haddr = address; + for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { pte_t *pte, entry; BUG_ON(PageCompound(page+i)); entry = mk_pte(page + i, vma->vm_page_prot); @@ -2017,8 +1985,6 @@ static void collapse_huge_page(struct mm_struct *mm, pte_unmap(pte); __SetPageUptodate(new_page); pgtable = pmd_pgtable(_pmd); - VM_BUG_ON(page_count(pgtable) != 1); - VM_BUG_ON(page_mapcount(pgtable) != 0); _pmd = mk_pmd(new_page, vma->vm_page_prot); _pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma); @@ -2036,7 +2002,7 @@ static void collapse_huge_page(struct mm_struct *mm, page_add_new_anon_rmap(new_page, vma, address); set_pmd_at(mm, address, pmd, _pmd); update_mmu_cache(vma, address, _pmd); - prepare_pmd_huge_pte(pgtable, mm); + pgtable_trans_huge_deposit(mm, pgtable); spin_unlock(&mm->page_table_lock); *hpage = NULL; -- cgit v1.2.1