ANDROID: vendor_hooks: add hooks for f2fs issue checkpoint

Add hooks to solve the priority inversion. while the key thread needs
to update fs data, it should wake and wait for f2fs checkpoint thread
to complete the work. So one scheme is needed to ensure the priority
of checkpoint thread especially in CPU high load scenarios.

Bug: 375088532
Change-Id: Iaa181cd1c8368310d9dd4c78adda6c7add5858b3
Signed-off-by: yipeng xiang <[email protected]>

Author: yipeng xiang

drivers/android/vendor_hooks.c

@@ -442,6 +442,8 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_oom_swapmem_gather_init);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_oom_swapmem_gather_finish);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_f2fs_file_open);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_f2fs_down_read);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_f2fs_improve_priority);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_f2fs_restore_priority);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_uplink_send_msg);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_inet_create);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_sock_create);

fs/f2fs/checkpoint.c

@@ -1903,10 +1903,18 @@ int f2fs_issue_checkpoint(struct f2fs_sb_info *sbi)
 	if (waitqueue_active(&cprc->ckpt_wait_queue))
 		wake_up(&cprc->ckpt_wait_queue);
 
-	if (cprc->f2fs_issue_ckpt)
+	if (cprc->f2fs_issue_ckpt) {
+		bool prio_changed = false;
+		int saved_prio;
+
+		trace_android_vh_f2fs_improve_priority(cprc->f2fs_issue_ckpt, &saved_prio,
+						&prio_changed);
 		wait_for_completion(&req.wait);
-	else
+		if (prio_changed)
+			trace_android_vh_f2fs_restore_priority(cprc->f2fs_issue_ckpt, saved_prio);
+	} else {
 		flush_remained_ckpt_reqs(sbi, &req);
+	}
 
 	return req.ret;
 }

include/trace/hooks/fs.h

@@ -20,6 +20,14 @@ DECLARE_RESTRICTED_HOOK(android_rvh_f2fs_down_read,
 	TP_PROTO(wait_queue_head_t *read_waiters, struct rw_semaphore *rwsem, bool *skip),
 	TP_ARGS(read_waiters, rwsem, skip), 1);
 
+DECLARE_HOOK(android_vh_f2fs_improve_priority,
+	TP_PROTO(struct task_struct *p, int *saved_prio, bool *skip),
+	TP_ARGS(p, saved_prio, skip));
+
+DECLARE_HOOK(android_vh_f2fs_restore_priority,
+	TP_PROTO(struct task_struct *p, int saved_prio),
+	TP_ARGS(p, saved_prio));
+
 #endif /* _TRACE_HOOK_FS_H */
 
 /* This part must be outside protection */