thp: prepare for DAX huge pages
Add a vma_is_dax() helper macro to test whether the VMA is DAX, and use it
in zap_huge_pmd() and __split_huge_page_pmd().
[akpm@linux-foundation.org: fix build]
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ca475df..9057241 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -16,6 +16,7 @@
#include <linux/swap.h>
#include <linux/shrinker.h>
#include <linux/mm_inline.h>
+#include <linux/dax.h>
#include <linux/kthread.h>
#include <linux/khugepaged.h>
#include <linux/freezer.h>
@@ -794,7 +795,7 @@
}
/* Caller must hold page table lock. */
-static bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
+bool set_huge_zero_page(pgtable_t pgtable, struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long haddr, pmd_t *pmd,
struct page *zero_page)
{
@@ -1421,7 +1422,6 @@
int ret = 0;
if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
- struct page *page;
pgtable_t pgtable;
pmd_t orig_pmd;
/*
@@ -1433,13 +1433,22 @@
orig_pmd = pmdp_huge_get_and_clear_full(tlb->mm, addr, pmd,
tlb->fullmm);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
- pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ if (vma_is_dax(vma)) {
+ if (is_huge_zero_pmd(orig_pmd)) {
+ pgtable = NULL;
+ } else {
+ spin_unlock(ptl);
+ return 1;
+ }
+ } else {
+ pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ }
if (is_huge_zero_pmd(orig_pmd)) {
atomic_long_dec(&tlb->mm->nr_ptes);
spin_unlock(ptl);
put_huge_zero_page();
} else {
- page = pmd_page(orig_pmd);
+ struct page *page = pmd_page(orig_pmd);
page_remove_rmap(page);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
@@ -1448,7 +1457,8 @@
spin_unlock(ptl);
tlb_remove_page(tlb, page);
}
- pte_free(tlb->mm, pgtable);
+ if (pgtable)
+ pte_free(tlb->mm, pgtable);
ret = 1;
}
return ret;
@@ -2914,7 +2924,7 @@
pmd_t *pmd)
{
spinlock_t *ptl;
- struct page *page;
+ struct page *page = NULL;
struct mm_struct *mm = vma->vm_mm;
unsigned long haddr = address & HPAGE_PMD_MASK;
unsigned long mmun_start; /* For mmu_notifiers */
@@ -2927,25 +2937,25 @@
again:
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptl = pmd_lock(mm, pmd);
- if (unlikely(!pmd_trans_huge(*pmd))) {
- spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- return;
- }
- if (is_huge_zero_pmd(*pmd)) {
+ if (unlikely(!pmd_trans_huge(*pmd)))
+ goto unlock;
+ if (vma_is_dax(vma)) {
+ pmdp_huge_clear_flush(vma, haddr, pmd);
+ } else if (is_huge_zero_pmd(*pmd)) {
__split_huge_zero_page_pmd(vma, haddr, pmd);
- spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- return;
+ } else {
+ page = pmd_page(*pmd);
+ VM_BUG_ON_PAGE(!page_count(page), page);
+ get_page(page);
}
- page = pmd_page(*pmd);
- VM_BUG_ON_PAGE(!page_count(page), page);
- get_page(page);
+ unlock:
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
- split_huge_page(page);
+ if (!page)
+ return;
+ split_huge_page(page);
put_page(page);
/*