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Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c98
1 files changed, 76 insertions, 22 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index aa68a4089a53..2e6257165527 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1122,7 +1122,7 @@ static void __page_check_anon_rmap(struct page *page,
* over the call to page_add_new_anon_rmap.
*/
BUG_ON(page_anon_vma(page)->root != vma->anon_vma->root);
- BUG_ON(page->index != linear_page_index(vma, address));
+ BUG_ON(page_to_pgoff(page) != linear_page_index(vma, address));
#endif
}
@@ -1152,9 +1152,28 @@ void page_add_anon_rmap(struct page *page,
void do_page_add_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address, int flags)
{
- int first = atomic_inc_and_test(&page->_mapcount);
+ bool compound = flags & RMAP_COMPOUND;
+ bool first;
+
+ if (PageTransCompound(page)) {
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+ if (compound) {
+ atomic_t *mapcount;
+
+ VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ mapcount = compound_mapcount_ptr(page);
+ first = atomic_inc_and_test(mapcount);
+ } else {
+ /* Anon THP always mapped first with PMD */
+ first = 0;
+ VM_BUG_ON_PAGE(!page_mapcount(page), page);
+ atomic_inc(&page->_mapcount);
+ }
+ } else {
+ first = atomic_inc_and_test(&page->_mapcount);
+ }
+
if (first) {
- bool compound = flags & RMAP_COMPOUND;
int nr = compound ? hpage_nr_pages(page) : 1;
/*
* We use the irq-unsafe __{inc|mod}_zone_page_stat because
@@ -1173,6 +1192,7 @@ void do_page_add_anon_rmap(struct page *page,
return;
VM_BUG_ON_PAGE(!PageLocked(page), page);
+
/* address might be in next vma when migration races vma_adjust */
if (first)
__page_set_anon_rmap(page, vma, address,
@@ -1199,10 +1219,16 @@ void page_add_new_anon_rmap(struct page *page,
VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
SetPageSwapBacked(page);
- atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */
if (compound) {
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
+ /* increment count (starts at -1) */
+ atomic_set(compound_mapcount_ptr(page), 0);
__inc_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+ } else {
+ /* Anon THP always mapped first with PMD */
+ VM_BUG_ON_PAGE(PageTransCompound(page), page);
+ /* increment count (starts at -1) */
+ atomic_set(&page->_mapcount, 0);
}
__mod_zone_page_state(page_zone(page), NR_ANON_PAGES, nr);
__page_set_anon_rmap(page, vma, address, 1);
@@ -1232,12 +1258,15 @@ static void page_remove_file_rmap(struct page *page)
memcg = mem_cgroup_begin_page_stat(page);
- /* page still mapped by someone else? */
- if (!atomic_add_negative(-1, &page->_mapcount))
+ /* Hugepages are not counted in NR_FILE_MAPPED for now. */
+ if (unlikely(PageHuge(page))) {
+ /* hugetlb pages are always mapped with pmds */
+ atomic_dec(compound_mapcount_ptr(page));
goto out;
+ }
- /* Hugepages are not counted in NR_FILE_MAPPED for now. */
- if (unlikely(PageHuge(page)))
+ /* page still mapped by someone else? */
+ if (!atomic_add_negative(-1, &page->_mapcount))
goto out;
/*
@@ -1254,6 +1283,39 @@ out:
mem_cgroup_end_page_stat(memcg);
}
+static void page_remove_anon_compound_rmap(struct page *page)
+{
+ int i, nr;
+
+ if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
+ return;
+
+ /* Hugepages are not counted in NR_ANON_PAGES for now. */
+ if (unlikely(PageHuge(page)))
+ return;
+
+ if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
+ return;
+
+ __dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
+
+ if (TestClearPageDoubleMap(page)) {
+ /*
+ * Subpages can be mapped with PTEs too. Check how many of
+ * themi are still mapped.
+ */
+ for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) {
+ if (atomic_add_negative(-1, &page[i]._mapcount))
+ nr++;
+ }
+ } else {
+ nr = HPAGE_PMD_NR;
+ }
+
+ if (nr)
+ __mod_zone_page_state(page_zone(page), NR_ANON_PAGES, -nr);
+}
+
/**
* page_remove_rmap - take down pte mapping from a page
* @page: page to remove mapping from
@@ -1263,33 +1325,25 @@ out:
*/
void page_remove_rmap(struct page *page, bool compound)
{
- int nr = compound ? hpage_nr_pages(page) : 1;
-
if (!PageAnon(page)) {
VM_BUG_ON_PAGE(compound && !PageHuge(page), page);
page_remove_file_rmap(page);
return;
}
+ if (compound)
+ return page_remove_anon_compound_rmap(page);
+
/* page still mapped by someone else? */
if (!atomic_add_negative(-1, &page->_mapcount))
return;
- /* Hugepages are not counted in NR_ANON_PAGES for now. */
- if (unlikely(PageHuge(page)))
- return;
-
/*
* We use the irq-unsafe __{inc|mod}_zone_page_stat because
* these counters are not modified in interrupt context, and
* pte lock(a spinlock) is held, which implies preemption disabled.
*/
- if (compound) {
- VM_BUG_ON_PAGE(!PageTransHuge(page), page);
- __dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
- }
-
- __mod_zone_page_state(page_zone(page), NR_ANON_PAGES, -nr);
+ __dec_zone_page_state(page, NR_ANON_PAGES);
if (unlikely(PageMlocked(page)))
clear_page_mlock(page);
@@ -1710,7 +1764,7 @@ void hugepage_add_anon_rmap(struct page *page,
BUG_ON(!PageLocked(page));
BUG_ON(!anon_vma);
/* address might be in next vma when migration races vma_adjust */
- first = atomic_inc_and_test(&page->_mapcount);
+ first = atomic_inc_and_test(compound_mapcount_ptr(page));
if (first)
__hugepage_set_anon_rmap(page, vma, address, 0);
}
@@ -1719,7 +1773,7 @@ void hugepage_add_new_anon_rmap(struct page *page,
struct vm_area_struct *vma, unsigned long address)
{
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
- atomic_set(&page->_mapcount, 0);
+ atomic_set(compound_mapcount_ptr(page), 0);
__hugepage_set_anon_rmap(page, vma, address, 1);
}
#endif /* CONFIG_HUGETLB_PAGE */