ANDROID: mm: Add vendor hook in filemap_get_folio()

Add a vendor hook for pagecache hit/miss and other
vendor specific functions.

Bug: 174088128
Bug: 172987241
Signed-off-by: Chiawei Wang <chiaweiwang@google.com>
Change-Id: Ie9f14a69a86b8ed81de766e44e30f2eba1d9bd84
Signed-off-by: Richard Chang <richardycc@google.com>
(cherry picked from commit db158b4ae0543446d38313c3da942afee9947267)
Signed-off-by: Jack Lee <liangjlee@google.com>
(cherry picked from commit cbac5cbf85540c043d1ddb917f288ebfe62bbca7)
Signed-off-by: Dmitry Skiba <dskiba@google.com>

drivers/android/vendor_hooks.c

@@ -424,3 +424,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_save_vmalloc_stack);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_show_stack_hash);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_exit_check);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_rmqueue);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_filemap_get_folio);

include/trace/hooks/mm.h

@@ -129,6 +129,10 @@ DECLARE_HOOK(android_vh_rmqueue,
 		unsigned int alloc_flags, int migratetype),
 	TP_ARGS(preferred_zone, zone, order,
 		gfp_flags, alloc_flags, migratetype));
+DECLARE_HOOK(android_vh_filemap_get_folio,
+	TP_PROTO(struct address_space *mapping, pgoff_t index,
+		int fgp_flags, gfp_t gfp_mask, struct folio *folio),
+	TP_ARGS(mapping, index, fgp_flags, gfp_mask, folio));
 DECLARE_HOOK(android_vh_meminfo_cache_adjust,
 	TP_PROTO(unsigned long *cached),
 	TP_ARGS(cached));

mm/filemap.c

@@ -1906,6 +1906,8 @@ repeat:
 	folio = filemap_get_entry(mapping, index);
 	if (xa_is_value(folio))
 		folio = NULL;
+	trace_android_vh_filemap_get_folio(mapping, index, fgp_flags,
+					gfp, folio);
 	if (!folio)
 		goto no_page;