With split pmd page table lock enabled, we don't use mm->page_table_lock when
updating pmd entries. This patch update hugetlb path to use the right lock
when inserting huge page directory entries into page table.
ex: if we are using hugepd and inserting hugepd entry at the pmd level, we
use pmd_lockptr, which based on config can be split pmd lock.
For update huge page directory entries itself we use mm->page_table_lock. We
do have a helper huge_pte_lockptr() for that.
Fixes: 675d99529 ("powerpc/book3s64: Enable split pmd ptlock")
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/mm/hugetlbpage.c | 33 +++++++++++++++++++++++----------
arch/powerpc/mm/pgtable.c | 12 +++++++-----
2 files changed, 30 insertions(+), 15 deletions(-)
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 2a4b1bf8bde6..7c5f479c5c00 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -52,7 +52,8 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long
addr, unsigned long s
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
- unsigned long address, unsigned pdshift, unsigned
pshift)
+ unsigned long address, unsigned int pdshift,
+ unsigned int pshift, spinlock_t *ptl)
{
struct kmem_cache *cachep;
pte_t *new;
@@ -82,8 +83,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t
*hpdp,
*/
smp_wmb();
- spin_lock(&mm->page_table_lock);
-
+ spin_lock(ptl);
/*
* We have multiple higher-level entries that point to the same
* actual pte location. Fill in each as we go and backtrack on error.
@@ -113,7 +113,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t
*hpdp,
*hpdp = __hugepd(0);
kmem_cache_free(cachep, new);
}
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(ptl);
return 0;
}
@@ -138,6 +138,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long
addr, unsigned long sz
hugepd_t *hpdp = NULL;
unsigned pshift = __ffs(sz);
unsigned pdshift = PGDIR_SHIFT;
+ spinlock_t *ptl;
addr &= ~(sz-1);
pg = pgd_offset(mm, addr);
@@ -146,39 +147,46 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long
addr, unsigned long sz
if (pshift == PGDIR_SHIFT)
/* 16GB huge page */
return (pte_t *) pg;
- else if (pshift > PUD_SHIFT)
+ else if (pshift > PUD_SHIFT) {
/*
* We need to use hugepd table
*/
+ ptl = &mm->page_table_lock;
hpdp = (hugepd_t *)pg;
- else {
+ } else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (pshift == PUD_SHIFT)
return (pte_t *)pu;
- else if (pshift > PMD_SHIFT)
+ else if (pshift > PMD_SHIFT) {
+ ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
- else {
+ } else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
if (pshift == PMD_SHIFT)
/* 16MB hugepage */
return (pte_t *)pm;
- else
+ else {
+ ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
+ }
}
}
#else
if (pshift >= HUGEPD_PGD_SHIFT) {
+ ptl = &mm->page_table_lock;
hpdp = (hugepd_t *)pg;
} else {
pdshift = PUD_SHIFT;
pu = pud_alloc(mm, pg, addr);
if (pshift >= HUGEPD_PUD_SHIFT) {
+ ptl = pud_lockptr(mm, pu);
hpdp = (hugepd_t *)pu;
} else {
pdshift = PMD_SHIFT;
pm = pmd_alloc(mm, pu, addr);
+ ptl = pmd_lockptr(mm, pm);
hpdp = (hugepd_t *)pm;
}
}
@@ -188,7 +196,8 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long
addr, unsigned long sz
BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
- if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift,
pshift))
+ if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
+ pdshift, pshift, ptl))
return NULL;
return hugepte_offset(*hpdp, addr, pdshift);
@@ -499,6 +508,10 @@ struct page *follow_huge_pd(struct vm_area_struct *vma,
struct mm_struct *mm = vma->vm_mm;
retry:
+ /*
+ * hugepage directory entries are protected by mm->page_table_lock
+ * Use this instead of huge_pte_lockptr
+ */
ptl = &mm->page_table_lock;
spin_lock(ptl);
diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c
index 5281c2c064af..d71c7777669c 100644
--- a/arch/powerpc/mm/pgtable.c
+++ b/arch/powerpc/mm/pgtable.c
@@ -249,17 +249,19 @@ extern int huge_ptep_set_access_flags(struct
vm_area_struct *vma,
if (changed) {
#ifdef CONFIG_PPC_BOOK3S_64
- struct hstate *hstate = hstate_file(vma->vm_file);
- psize = hstate_get_psize(hstate);
+ struct hstate *h = hstate_vma(vma);
+
+ psize = hstate_get_psize(h);
+#ifdef CONFIG_DEBUG_VM
+ assert_spin_locked(huge_pte_lockptr(h, vma->vm_mm, ptep));
+#endif
+
#else
/*
* Not used on non book3s64 platforms. But 8xx
* can possibly use tsize derived from hstate.
*/
psize = 0;
-#endif
-#ifdef CONFIG_DEBUG_VM
- assert_spin_locked(&vma->vm_mm->page_table_lock);
#endif
__ptep_set_access_flags(vma, ptep, pte, addr, psize);
}
--
2.17.0
