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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2013-11-15 02:31:02 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-15 04:32:14 +0400
commitcb900f41215447433cbc456d1c4294e858a84d7c (patch)
tree1f3704d9a023a20baa2872d6639a58387ef2d7c2 /mm/hugetlb.c
parentc389a250ab4cfa4a3775d9f2c45271618af6d5b2 (diff)
downloadlinux-cb900f41215447433cbc456d1c4294e858a84d7c.tar.xz
mm, hugetlb: convert hugetlbfs to use split pmd lock
Hugetlb supports multiple page sizes. We use split lock only for PMD level, but not for PUD. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Tested-by: Alex Thorlton <athorlton@sgi.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: "Paul E . McKenney" <paulmck@linux.vnet.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: David Howells <dhowells@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kees Cook <keescook@chromium.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Robin Holt <robinmholt@gmail.com> Cc: Sedat Dilek <sedat.dilek@gmail.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c110
1 files changed, 66 insertions, 44 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 0b7656e804d1..7d57af21f49e 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2376,6 +2376,7 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
+ spinlock_t *src_ptl, *dst_ptl;
src_pte = huge_pte_offset(src, addr);
if (!src_pte)
continue;
@@ -2387,8 +2388,9 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
if (dst_pte == src_pte)
continue;
- spin_lock(&dst->page_table_lock);
- spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
+ dst_ptl = huge_pte_lock(h, dst, dst_pte);
+ src_ptl = huge_pte_lockptr(h, src, src_pte);
+ spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
if (!huge_pte_none(huge_ptep_get(src_pte))) {
if (cow)
huge_ptep_set_wrprotect(src, addr, src_pte);
@@ -2398,8 +2400,8 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
page_dup_rmap(ptepage);
set_huge_pte_at(dst, addr, dst_pte, entry);
}
- spin_unlock(&src->page_table_lock);
- spin_unlock(&dst->page_table_lock);
+ spin_unlock(src_ptl);
+ spin_unlock(dst_ptl);
}
return 0;
@@ -2442,6 +2444,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
unsigned long address;
pte_t *ptep;
pte_t pte;
+ spinlock_t *ptl;
struct page *page;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
@@ -2455,25 +2458,25 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
tlb_start_vma(tlb, vma);
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
again:
- spin_lock(&mm->page_table_lock);
for (address = start; address < end; address += sz) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
+ ptl = huge_pte_lock(h, mm, ptep);
if (huge_pmd_unshare(mm, &address, ptep))
- continue;
+ goto unlock;
pte = huge_ptep_get(ptep);
if (huge_pte_none(pte))
- continue;
+ goto unlock;
/*
* HWPoisoned hugepage is already unmapped and dropped reference
*/
if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
huge_pte_clear(mm, address, ptep);
- continue;
+ goto unlock;
}
page = pte_page(pte);
@@ -2484,7 +2487,7 @@ again:
*/
if (ref_page) {
if (page != ref_page)
- continue;
+ goto unlock;
/*
* Mark the VMA as having unmapped its page so that
@@ -2501,13 +2504,18 @@ again:
page_remove_rmap(page);
force_flush = !__tlb_remove_page(tlb, page);
- if (force_flush)
+ if (force_flush) {
+ spin_unlock(ptl);
break;
+ }
/* Bail out after unmapping reference page if supplied */
- if (ref_page)
+ if (ref_page) {
+ spin_unlock(ptl);
break;
+ }
+unlock:
+ spin_unlock(ptl);
}
- spin_unlock(&mm->page_table_lock);
/*
* mmu_gather ran out of room to batch pages, we break out of
* the PTE lock to avoid doing the potential expensive TLB invalidate
@@ -2613,7 +2621,7 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
*/
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *ptep, pte_t pte,
- struct page *pagecache_page)
+ struct page *pagecache_page, spinlock_t *ptl)
{
struct hstate *h = hstate_vma(vma);
struct page *old_page, *new_page;
@@ -2647,8 +2655,8 @@ retry_avoidcopy:
page_cache_get(old_page);
- /* Drop page_table_lock as buddy allocator may be called */
- spin_unlock(&mm->page_table_lock);
+ /* Drop page table lock as buddy allocator may be called */
+ spin_unlock(ptl);
new_page = alloc_huge_page(vma, address, outside_reserve);
if (IS_ERR(new_page)) {
@@ -2666,13 +2674,13 @@ retry_avoidcopy:
BUG_ON(huge_pte_none(pte));
if (unmap_ref_private(mm, vma, old_page, address)) {
BUG_ON(huge_pte_none(pte));
- spin_lock(&mm->page_table_lock);
+ spin_lock(ptl);
ptep = huge_pte_offset(mm, address & huge_page_mask(h));
if (likely(pte_same(huge_ptep_get(ptep), pte)))
goto retry_avoidcopy;
/*
- * race occurs while re-acquiring page_table_lock, and
- * our job is done.
+ * race occurs while re-acquiring page table
+ * lock, and our job is done.
*/
return 0;
}
@@ -2680,7 +2688,7 @@ retry_avoidcopy:
}
/* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
+ spin_lock(ptl);
if (err == -ENOMEM)
return VM_FAULT_OOM;
else
@@ -2695,7 +2703,7 @@ retry_avoidcopy:
page_cache_release(new_page);
page_cache_release(old_page);
/* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
+ spin_lock(ptl);
return VM_FAULT_OOM;
}
@@ -2707,10 +2715,10 @@ retry_avoidcopy:
mmun_end = mmun_start + huge_page_size(h);
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
/*
- * Retake the page_table_lock to check for racing updates
+ * Retake the page table lock to check for racing updates
* before the page tables are altered
*/
- spin_lock(&mm->page_table_lock);
+ spin_lock(ptl);
ptep = huge_pte_offset(mm, address & huge_page_mask(h));
if (likely(pte_same(huge_ptep_get(ptep), pte))) {
ClearPagePrivate(new_page);
@@ -2724,13 +2732,13 @@ retry_avoidcopy:
/* Make the old page be freed below */
new_page = old_page;
}
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
page_cache_release(new_page);
page_cache_release(old_page);
/* Caller expects lock to be held */
- spin_lock(&mm->page_table_lock);
+ spin_lock(ptl);
return 0;
}
@@ -2778,6 +2786,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page *page;
struct address_space *mapping;
pte_t new_pte;
+ spinlock_t *ptl;
/*
* Currently, we are forced to kill the process in the event the
@@ -2864,7 +2873,8 @@ retry:
goto backout_unlocked;
}
- spin_lock(&mm->page_table_lock);
+ ptl = huge_pte_lockptr(h, mm, ptep);
+ spin_lock(ptl);
size = i_size_read(mapping->host) >> huge_page_shift(h);
if (idx >= size)
goto backout;
@@ -2885,16 +2895,16 @@ retry:
if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
/* Optimization, do the COW without a second fault */
- ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
+ ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page, ptl);
}
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(ptl);
unlock_page(page);
out:
return ret;
backout:
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(ptl);
backout_unlocked:
unlock_page(page);
put_page(page);
@@ -2906,6 +2916,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
{
pte_t *ptep;
pte_t entry;
+ spinlock_t *ptl;
int ret;
struct page *page = NULL;
struct page *pagecache_page = NULL;
@@ -2918,7 +2929,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (ptep) {
entry = huge_ptep_get(ptep);
if (unlikely(is_hugetlb_entry_migration(entry))) {
- migration_entry_wait_huge(mm, ptep);
+ migration_entry_wait_huge(vma, mm, ptep);
return 0;
} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
return VM_FAULT_HWPOISON_LARGE |
@@ -2974,17 +2985,18 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (page != pagecache_page)
lock_page(page);
- spin_lock(&mm->page_table_lock);
+ ptl = huge_pte_lockptr(h, mm, ptep);
+ spin_lock(ptl);
/* Check for a racing update before calling hugetlb_cow */
if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
- goto out_page_table_lock;
+ goto out_ptl;
if (flags & FAULT_FLAG_WRITE) {
if (!huge_pte_write(entry)) {
ret = hugetlb_cow(mm, vma, address, ptep, entry,
- pagecache_page);
- goto out_page_table_lock;
+ pagecache_page, ptl);
+ goto out_ptl;
}
entry = huge_pte_mkdirty(entry);
}
@@ -2993,8 +3005,8 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
flags & FAULT_FLAG_WRITE))
update_mmu_cache(vma, address, ptep);
-out_page_table_lock:
- spin_unlock(&mm->page_table_lock);
+out_ptl:
+ spin_unlock(ptl);
if (pagecache_page) {
unlock_page(pagecache_page);
@@ -3020,9 +3032,9 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long remainder = *nr_pages;
struct hstate *h = hstate_vma(vma);
- spin_lock(&mm->page_table_lock);
while (vaddr < vma->vm_end && remainder) {
pte_t *pte;
+ spinlock_t *ptl = NULL;
int absent;
struct page *page;
@@ -3030,8 +3042,12 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
* Some archs (sparc64, sh*) have multiple pte_ts to
* each hugepage. We have to make sure we get the
* first, for the page indexing below to work.
+ *
+ * Note that page table lock is not held when pte is null.
*/
pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
+ if (pte)
+ ptl = huge_pte_lock(h, mm, pte);
absent = !pte || huge_pte_none(huge_ptep_get(pte));
/*
@@ -3043,6 +3059,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
*/
if (absent && (flags & FOLL_DUMP) &&
!hugetlbfs_pagecache_present(h, vma, vaddr)) {
+ if (pte)
+ spin_unlock(ptl);
remainder = 0;
break;
}
@@ -3062,10 +3080,10 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
!huge_pte_write(huge_ptep_get(pte)))) {
int ret;
- spin_unlock(&mm->page_table_lock);
+ if (pte)
+ spin_unlock(ptl);
ret = hugetlb_fault(mm, vma, vaddr,
(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
- spin_lock(&mm->page_table_lock);
if (!(ret & VM_FAULT_ERROR))
continue;
@@ -3096,8 +3114,8 @@ same_page:
*/
goto same_page;
}
+ spin_unlock(ptl);
}
- spin_unlock(&mm->page_table_lock);
*nr_pages = remainder;
*position = vaddr;
@@ -3118,13 +3136,15 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
flush_cache_range(vma, address, end);
mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
- spin_lock(&mm->page_table_lock);
for (; address < end; address += huge_page_size(h)) {
+ spinlock_t *ptl;
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
+ ptl = huge_pte_lock(h, mm, ptep);
if (huge_pmd_unshare(mm, &address, ptep)) {
pages++;
+ spin_unlock(ptl);
continue;
}
if (!huge_pte_none(huge_ptep_get(ptep))) {
@@ -3134,8 +3154,8 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
set_huge_pte_at(mm, address, ptep, pte);
pages++;
}
+ spin_unlock(ptl);
}
- spin_unlock(&mm->page_table_lock);
/*
* Must flush TLB before releasing i_mmap_mutex: x86's huge_pmd_unshare
* may have cleared our pud entry and done put_page on the page table:
@@ -3298,6 +3318,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
unsigned long saddr;
pte_t *spte = NULL;
pte_t *pte;
+ spinlock_t *ptl;
if (!vma_shareable(vma, addr))
return (pte_t *)pmd_alloc(mm, pud, addr);
@@ -3320,13 +3341,14 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
if (!spte)
goto out;
- spin_lock(&mm->page_table_lock);
+ ptl = huge_pte_lockptr(hstate_vma(vma), mm, spte);
+ spin_lock(ptl);
if (pud_none(*pud))
pud_populate(mm, pud,
(pmd_t *)((unsigned long)spte & PAGE_MASK));
else
put_page(virt_to_page(spte));
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(ptl);
out:
pte = (pte_t *)pmd_alloc(mm, pud, addr);
mutex_unlock(&mapping->i_mmap_mutex);
@@ -3340,7 +3362,7 @@ out:
* indicated by page_count > 1, unmap is achieved by clearing pud and
* decrementing the ref count. If count == 1, the pte page is not shared.
*
- * called with vma->vm_mm->page_table_lock held.
+ * called with page table lock held.
*
* returns: 1 successfully unmapped a shared pte page
* 0 the underlying pte page is not shared, or it is the last user