memfd: Convert memfd_tag_pins to XArray (ef3038a5) · Commits · 戴 / test

mm/memfd.c

+18 −26

Original line number	Diff line number	Diff line
		@@ -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);

		xas_lock_irq(xas);
		xas_for_each(xas, page, ULONG_MAX) {
		if (xa_is_value(page))
		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 (page_count(page) - page_mapcount(page) > 1)
		xas_set_mark(xas, MEMFD_TAG_PINNED);

		if (need_resched()) {
		slot = radix_tree_iter_resume(slot, &iter);
		cond_resched_rcu();
		}
		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++) {