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 <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>
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8faaebd..42b5cf5 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -506,9 +506,9 @@
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 @@
{
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 @@
if (err)
break;
}
- spin_unlock(&walk->mm->page_table_lock);
+ spin_unlock(ptl);
return err;
}
@@ -1325,7 +1326,7 @@
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 @@
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 3935428..4aca0d8 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -129,15 +129,15 @@
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 @@
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 e5b2d31..471eb04 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1376,9 +1376,10 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
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 e3cd40b..f1a0ae6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6605,10 +6605,10 @@
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 @@
* 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 @@
}
put_page(page);
}
- spin_unlock(&vma->vm_mm->page_table_lock);
+ spin_unlock(ptl);
return 0;
}