Switch to a batch-processing model like memfd_wait_for_pins() and
use the xa_state previously set up by memfd_wait_for_pins().
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
mm/memfd.c | 44 ++++++++++++++++++--------------------------
1 file changed, 18 insertions(+), 26 deletions(-)
diff --git a/mm/memfd.c b/mm/memfd.c
index e7d6be725b7a..636de8d5c7c3 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -28,37 +28,29 @@
#define MEMFD_TAG_PINNED PAGECACHE_TAG_TOWRITE
#define LAST_SCAN 4 /* about 150ms max */
-static void memfd_tag_pins(struct address_space *mapping)
+static void memfd_tag_pins(struct xa_state *xas)
{
- struct radix_tree_iter iter;
- void __rcu **slot;
- pgoff_t start;
struct page *page;
+ unsigned int tagged = 0;
lru_add_drain();
- start = 0;
- rcu_read_lock();
-
- radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) {
- page = radix_tree_deref_slot(slot);
- if (!page || radix_tree_exception(page)) {
- if (radix_tree_deref_retry(page)) {
- slot = radix_tree_iter_retry(&iter);
- continue;
- }
- } else if (page_count(page) - page_mapcount(page) > 1) {
- xa_lock_irq(&mapping->i_pages);
- radix_tree_tag_set(&mapping->i_pages, iter.index,
- MEMFD_TAG_PINNED);
- xa_unlock_irq(&mapping->i_pages);
- }
- if (need_resched()) {
- slot = radix_tree_iter_resume(slot, &iter);
- cond_resched_rcu();
- }
+ xas_lock_irq(xas);
+ xas_for_each(xas, page, ULONG_MAX) {
+ if (xa_is_value(page))
+ continue;
+ if (page_count(page) - page_mapcount(page) > 1)
+ xas_set_tag(xas, MEMFD_TAG_PINNED);
+
+ if (++tagged % XA_CHECK_SCHED)
+ continue;
+
+ xas_pause(xas);
+ xas_unlock_irq(xas);
+ cond_resched();
+ xas_lock_irq(xas);
}
- rcu_read_unlock();
+ xas_unlock_irq(xas);
}
/*
@@ -76,7 +68,7 @@ static int memfd_wait_for_pins(struct address_space *mapping)
struct page *page;
int error, scan;
- memfd_tag_pins(mapping);
+ memfd_tag_pins(&xas);
error = 0;
for (scan = 0; scan <= LAST_SCAN; scan++) {
--
2.17.1
