From bf929152e9f6c49b66fad4ebf08cc95b02ce48f5 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Thu, 14 Nov 2013 14:30:54 -0800 Subject: [PATCH] mm, thp: change pmd_trans_huge_lock() to return taken lock With split ptlock it's important to know which lock pmd_trans_huge_lock() took. This patch adds one more parameter to the function to return the lock. In most places migration to new api is trivial. Exception is move_huge_pmd(): we need to take two locks if pmd tables are different. Signed-off-by: Naoya Horiguchi Signed-off-by: Kirill A. Shutemov Tested-by: Alex Thorlton Cc: Ingo Molnar Cc: "Eric W . Biederman" Cc: "Paul E . McKenney" Cc: Al Viro Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Dave Hansen Cc: Dave Jones Cc: David Howells Cc: Frederic Weisbecker Cc: Johannes Weiner Cc: Kees Cook Cc: Mel Gorman Cc: Michael Kerrisk Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Robin Holt Cc: Sedat Dilek Cc: Srikar Dronamraju Cc: Thomas Gleixner Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/task_mmu.c | 13 +++++++------ include/linux/huge_mm.h | 14 +++++++------- mm/huge_memory.c | 40 +++++++++++++++++++++++++++------------- mm/memcontrol.c | 10 +++++----- 4 files changed, 46 insertions(+), 31 deletions(-) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 8faaebdc6b02..42b5cf5d0326 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -506,9 +506,9 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, pte_t *pte; spinlock_t *ptl; - if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { smaps_pte_entry(*(pte_t *)pmd, addr, HPAGE_PMD_SIZE, walk); - spin_unlock(&walk->mm->page_table_lock); + spin_unlock(ptl); mss->anonymous_thp += HPAGE_PMD_SIZE; return 0; } @@ -999,13 +999,14 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, { struct vm_area_struct *vma; struct pagemapread *pm = walk->private; + spinlock_t *ptl; pte_t *pte; int err = 0; pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2)); /* find the first VMA at or above 'addr' */ vma = find_vma(walk->mm, addr); - if (vma && pmd_trans_huge_lock(pmd, vma) == 1) { + if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { int pmd_flags2; if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd)) @@ -1023,7 +1024,7 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, if (err) break; } - spin_unlock(&walk->mm->page_table_lock); + spin_unlock(ptl); return err; } @@ -1325,7 +1326,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr, md = walk->private; - if (pmd_trans_huge_lock(pmd, md->vma) == 1) { + if (pmd_trans_huge_lock(pmd, md->vma, &ptl) == 1) { pte_t huge_pte = *(pte_t *)pmd; struct page *page; @@ -1333,7 +1334,7 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr, if (page) gather_stats(page, md, pte_dirty(huge_pte), HPAGE_PMD_SIZE/PAGE_SIZE); - spin_unlock(&walk->mm->page_table_lock); + spin_unlock(ptl); return 0; } diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 3935428c57cf..4aca0d8da112 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -129,15 +129,15 @@ extern void __vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start, unsigned long end, long adjust_next); -extern int __pmd_trans_huge_lock(pmd_t *pmd, - struct vm_area_struct *vma); +extern int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, + spinlock_t **ptl); /* mmap_sem must be held on entry */ -static inline int pmd_trans_huge_lock(pmd_t *pmd, - struct vm_area_struct *vma) +static inline int pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, + spinlock_t **ptl) { VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem)); if (pmd_trans_huge(*pmd)) - return __pmd_trans_huge_lock(pmd, vma); + return __pmd_trans_huge_lock(pmd, vma, ptl); else return 0; } @@ -215,8 +215,8 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma, long adjust_next) { } -static inline int pmd_trans_huge_lock(pmd_t *pmd, - struct vm_area_struct *vma) +static inline int pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, + spinlock_t **ptl) { return 0; } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e5b2d316be2e..471eb04066ff 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1376,9 +1376,10 @@ out: int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr) { + spinlock_t *ptl; int ret = 0; - if (__pmd_trans_huge_lock(pmd, vma) == 1) { + if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { struct page *page; pgtable_t pgtable; pmd_t orig_pmd; @@ -1393,7 +1394,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd); if (is_huge_zero_pmd(orig_pmd)) { atomic_long_dec(&tlb->mm->nr_ptes); - spin_unlock(&tlb->mm->page_table_lock); + spin_unlock(ptl); put_huge_zero_page(); } else { page = pmd_page(orig_pmd); @@ -1402,7 +1403,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); VM_BUG_ON(!PageHead(page)); atomic_long_dec(&tlb->mm->nr_ptes); - spin_unlock(&tlb->mm->page_table_lock); + spin_unlock(ptl); tlb_remove_page(tlb, page); } pte_free(tlb->mm, pgtable); @@ -1415,14 +1416,15 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, unsigned long end, unsigned char *vec) { + spinlock_t *ptl; int ret = 0; - if (__pmd_trans_huge_lock(pmd, vma) == 1) { + if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { /* * All logical pages in the range are present * if backed by a huge page. */ - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); memset(vec, 1, (end - addr) >> PAGE_SHIFT); ret = 1; } @@ -1435,6 +1437,7 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, unsigned long new_addr, unsigned long old_end, pmd_t *old_pmd, pmd_t *new_pmd) { + spinlock_t *old_ptl, *new_ptl; int ret = 0; pmd_t pmd; @@ -1455,12 +1458,21 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, goto out; } - ret = __pmd_trans_huge_lock(old_pmd, vma); + /* + * We don't have to worry about the ordering of src and dst + * ptlocks because exclusive mmap_sem prevents deadlock. + */ + ret = __pmd_trans_huge_lock(old_pmd, vma, &old_ptl); if (ret == 1) { + new_ptl = pmd_lockptr(mm, new_pmd); + if (new_ptl != old_ptl) + spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING); pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); VM_BUG_ON(!pmd_none(*new_pmd)); set_pmd_at(mm, new_addr, new_pmd, pmd_mksoft_dirty(pmd)); - spin_unlock(&mm->page_table_lock); + if (new_ptl != old_ptl) + spin_unlock(new_ptl); + spin_unlock(old_ptl); } out: return ret; @@ -1476,9 +1488,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, pgprot_t newprot, int prot_numa) { struct mm_struct *mm = vma->vm_mm; + spinlock_t *ptl; int ret = 0; - if (__pmd_trans_huge_lock(pmd, vma) == 1) { + if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { pmd_t entry; ret = 1; if (!prot_numa) { @@ -1507,7 +1520,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, if (ret == HPAGE_PMD_NR) set_pmd_at(mm, addr, pmd, entry); - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); } return ret; @@ -1520,12 +1533,13 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, * Note that if it returns 1, this routine returns without unlocking page * table locks. So callers must unlock them. */ -int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) +int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma, + spinlock_t **ptl) { - spin_lock(&vma->vm_mm->page_table_lock); + *ptl = pmd_lock(vma->vm_mm, pmd); if (likely(pmd_trans_huge(*pmd))) { if (unlikely(pmd_trans_splitting(*pmd))) { - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(*ptl); wait_split_huge_page(vma->anon_vma, pmd); return -1; } else { @@ -1534,7 +1548,7 @@ int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) return 1; } } - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(*ptl); return 0; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e3cd40b2d5d9..f1a0ae6e11b8 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6605,10 +6605,10 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, pte_t *pte; spinlock_t *ptl; - if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE) mc.precharge += HPAGE_PMD_NR; - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } @@ -6797,9 +6797,9 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, * to be unlocked in __split_huge_page_splitting(), where the main * part of thp split is not executed yet. */ - if (pmd_trans_huge_lock(pmd, vma) == 1) { + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) { if (mc.precharge < HPAGE_PMD_NR) { - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } target_type = get_mctgt_type_thp(vma, addr, *pmd, &target); @@ -6816,7 +6816,7 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, } put_page(page); } - spin_unlock(&vma->vm_mm->page_table_lock); + spin_unlock(ptl); return 0; } -- 2.34.1