ANDROID: vendor_hook: Add hook to not be stuck ro rmap lock in kswapd or direct_reclaim

Add hooks to support trylock in rmaplock when reclaiming in kswapd or
direct_reclaim, in order to avoid wait lock for a long time.

- android_vh_handle_failed_page_trylock
- android_vh_page_trylock_set
- android_vh_page_trylock_clear
- android_vh_page_trylock_get_result
- android_vh_do_page_trylock

Bug: 240003372

Signed-off-by: Peifeng Li <lipeifeng@oppo.com>
Change-Id: I0f605b35ae41f15b3ca7bc72cd5f003175c318a5

mm/rmap.c

@@ -525,6 +525,7 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page)
 	struct anon_vma *anon_vma = NULL;
 	struct anon_vma *root_anon_vma;
 	unsigned long anon_mapping;
+	bool success = false;
 
 	rcu_read_lock();
 	anon_mapping = (unsigned long)READ_ONCE(page->mapping);
@@ -547,7 +548,11 @@ struct anon_vma *page_lock_anon_vma_read(struct page *page)
 		}
 		goto out;
 	}
-
+	trace_android_vh_do_page_trylock(page, NULL, NULL, &success);
+	if (success) {
+		anon_vma = NULL;
+		goto out;
+	}
 	/* trylock failed, we got to sleep */
 	if (!atomic_inc_not_zero(&anon_vma->refcount)) {
 		anon_vma = NULL;
@@ -1981,6 +1986,7 @@ static void rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
 	struct address_space *mapping = page_mapping(page);
 	pgoff_t pgoff_start, pgoff_end;
 	struct vm_area_struct *vma;
+	bool got_lock = false, success = false;
 
 	/*
 	 * The page lock not only makes sure that page->mapping cannot
@@ -1995,8 +2001,16 @@ static void rmap_walk_file(struct page *page, struct rmap_walk_control *rwc,
 
 	pgoff_start = page_to_pgoff(page);
 	pgoff_end = pgoff_start + thp_nr_pages(page) - 1;
-	if (!locked)
-		i_mmap_lock_read(mapping);
+	if (!locked) {
+		trace_android_vh_do_page_trylock(page,
+					&mapping->i_mmap_rwsem, &got_lock, &success);
+		if (success) {
+			if (!got_lock)
+				return;
+		} else {
+			i_mmap_lock_read(mapping);
+		}
+	}
 	vma_interval_tree_foreach(vma, &mapping->i_mmap,
 			pgoff_start, pgoff_end) {
 		unsigned long address = vma_address(page, vma);