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mm, thp: move ptl taking inside page_check_address_pmd()

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With split page table lock we can't know which lock we need to take
before we find the relevant pmd.

Let's move lock taking inside the function.

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>
This commit is contained in:
Kirill A. Shutemov 2013-11-14 14:30:56 -08:00 committed by Linus Torvalds
parent bf929152e9
commit 117b0791ac
3 changed files with 34 additions and 25 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
include/linux/huge_mm.h
View file

@ -54,7 +54,8 @@ enum page_check_address_pmd_flag {
extern pmd_t *page_check_address_pmd(struct page *page,
struct mm_struct *mm,
unsigned long address,
enum page_check_address_pmd_flag flag);
enum page_check_address_pmd_flag flag,
spinlock_t **ptl);
#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)

43
mm/huge_memory.c
View file

@ -1552,23 +1552,33 @@ int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma,
return 0;
}
/*
* This function returns whether a given @page is mapped onto the @address
* in the virtual space of @mm.
*
* When it's true, this function returns *pmd with holding the page table lock
* and passing it back to the caller via @ptl.
* If it's false, returns NULL without holding the page table lock.
*/
pmd_t *page_check_address_pmd(struct page *page,
struct mm_struct *mm,
unsigned long address,
enum page_check_address_pmd_flag flag)
enum page_check_address_pmd_flag flag,
spinlock_t **ptl)
{
pmd_t *pmd, *ret = NULL;
pmd_t *pmd;
if (address & ~HPAGE_PMD_MASK)
goto out;
return NULL;
pmd = mm_find_pmd(mm, address);
if (!pmd)
goto out;
return NULL;
*ptl = pmd_lock(mm, pmd);
if (pmd_none(*pmd))
goto out;
goto unlock;
if (pmd_page(*pmd) != page)
goto out;
goto unlock;
/*
* split_vma() may create temporary aliased mappings. There is
* no risk as long as all huge pmd are found and have their
@ -1578,14 +1588,15 @@ pmd_t *page_check_address_pmd(struct page *page,
*/
if (flag == PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG &&
pmd_trans_splitting(*pmd))
goto out;
goto unlock;
if (pmd_trans_huge(*pmd)) {
VM_BUG_ON(flag == PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG &&
!pmd_trans_splitting(*pmd));
ret = pmd;
return pmd;
}
out:
return ret;
unlock:
spin_unlock(*ptl);
return NULL;
}
static int __split_huge_page_splitting(struct page *page,
@ -1593,6 +1604,7 @@ static int __split_huge_page_splitting(struct page *page,
unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
spinlock_t *ptl;
pmd_t *pmd;
int ret = 0;
/* For mmu_notifiers */
@ -1600,9 +1612,8 @@ static int __split_huge_page_splitting(struct page *page,
const unsigned long mmun_end = address + HPAGE_PMD_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
spin_lock(&mm->page_table_lock);
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG);
PAGE_CHECK_ADDRESS_PMD_NOTSPLITTING_FLAG, &ptl);
if (pmd) {
/*
* We can't temporarily set the pmd to null in order
@ -1613,8 +1624,8 @@ static int __split_huge_page_splitting(struct page *page,
*/
pmdp_splitting_flush(vma, address, pmd);
ret = 1;
spin_unlock(ptl);
}
spin_unlock(&mm->page_table_lock);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
return ret;
@ -1745,14 +1756,14 @@ static int __split_huge_page_map(struct page *page,
unsigned long address)
{
struct mm_struct *mm = vma->vm_mm;
spinlock_t *ptl;
pmd_t *pmd, _pmd;
int ret = 0, i;
pgtable_t pgtable;
unsigned long haddr;
spin_lock(&mm->page_table_lock);
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG, &ptl);
if (pmd) {
pgtable = pgtable_trans_huge_withdraw(mm, pmd);
pmd_populate(mm, &_pmd, pgtable);
@ -1807,8 +1818,8 @@ static int __split_huge_page_map(struct page *page,
pmdp_invalidate(vma, address, pmd);
pmd_populate(mm, pmd, pgtable);
ret = 1;
spin_unlock(ptl);
}
spin_unlock(&mm->page_table_lock);
return ret;
}

13
mm/rmap.c
View file

@ -665,25 +665,23 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
unsigned long *vm_flags)
{
struct mm_struct *mm = vma->vm_mm;
spinlock_t *ptl;
int referenced = 0;
if (unlikely(PageTransHuge(page))) {
pmd_t *pmd;
spin_lock(&mm->page_table_lock);
/*
* rmap might return false positives; we must filter
* these out using page_check_address_pmd().
*/
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_FLAG);
if (!pmd) {
spin_unlock(&mm->page_table_lock);
PAGE_CHECK_ADDRESS_PMD_FLAG, &ptl);
if (!pmd)
goto out;
}
if (vma->vm_flags & VM_LOCKED) {
spin_unlock(&mm->page_table_lock);
spin_unlock(ptl);
*mapcount = 0; /* break early from loop */
*vm_flags |= VM_LOCKED;
goto out;
@ -692,10 +690,9 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
/* go ahead even if the pmd is pmd_trans_splitting() */
if (pmdp_clear_flush_young_notify(vma, address, pmd))
referenced++;
spin_unlock(&mm->page_table_lock);
spin_unlock(ptl);
} else {
pte_t *pte;
spinlock_t *ptl;
/*
* rmap might return false positives; we must filter