ANDROID: vendor_hook: add vendor hook on calculate_totalreserve_pages

This vendor hook enables or disables updating the LMKD zone watermark level.

Bug: 396115949
Test: build
Change-Id: I0089a0586821120e47c46e08bcfea11a1602d516
Signed-off-by: Martin Liu <liumartin@google.com>

drivers/android/vendor_hooks.c

@@ -512,3 +512,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_compaction_try_to_compact_exit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_direct_reclaim_enter);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_direct_reclaim_exit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_mm_may_oom_exit);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_calculate_totalreserve_pages);

include/trace/hooks/mm.h

@@ -444,6 +444,9 @@ struct oom_control;
 DECLARE_HOOK(android_vh_mm_may_oom_exit,
 	TP_PROTO(struct oom_control *oc, unsigned long did_some_progress),
 	TP_ARGS(oc, did_some_progress));
+DECLARE_HOOK(android_vh_calculate_totalreserve_pages,
+	TP_PROTO(bool *skip),
+	TP_ARGS(skip));
 #endif /* _TRACE_HOOK_MM_H */
 
 /* This part must be outside protection */

mm/page_alloc.c

@@ -6330,6 +6330,7 @@ static void calculate_totalreserve_pages(void)
 	struct pglist_data *pgdat;
 	unsigned long reserve_pages = 0;
 	enum zone_type i, j;
+	bool skip = false;
 
 	for_each_online_pgdat(pgdat) {
 
@@ -6358,6 +6359,9 @@ static void calculate_totalreserve_pages(void)
 		}
 	}
 	totalreserve_pages = reserve_pages;
+	trace_android_vh_calculate_totalreserve_pages(&skip);
+	if (skip)
+		return;
 	trace_mm_calculate_totalreserve_pages(totalreserve_pages);
 }