DAOS-18487 object: control EC rebuild resource consumption (#17441)

dd resource controls to limit scanner pressure and improve stability:

Introduce resource control for rebuild scanning to prevent excessive load
and contention during rebuild/reclaim operations. The scanner now enforces
tighter pacing/limits (credits/yielding and related controls) so rebuild
work progresses without overwhelming system resources.

This improves cluster stability under heavy rebuild activity and reduces
the likelihood of prolonged stalls caused by resource exhaustion or
oversubscription, while preserving existing rebuild correctness and
behavior.

Signed-off-by: Liang Zhen <gnailzenh@gmail.com>
Signed-off-by: Wang Shilong <shilong.wang@hpe.com>
Signed-off-by: Mohamad Chaarawi <mohamad.chaarawi@hpe.com>

Author: gnailzenh

src/object/srv_internal.h

@@ -26,7 +26,29 @@
 
 extern struct dss_module_key obj_module_key;
 
-struct migr_res_manager;
+/* anchor point of resource waiter
+ * NB: resource control can be a independent library in the future.
+ */
+struct migr_res_waiter {
+	struct migrate_pool_tls *rw_tls;
+	/* link chain on resource manager */
+	d_list_t                 rw_link;
+	/* quantity of resource being demanded */
+	uint64_t                 rw_units;
+	/* start to wait since... */
+	uint64_t                 rw_wait_since;
+	/* eventual to wait on */
+	ABT_eventual             rw_eventual;
+	/* for eventual */
+	int                     *rw_rc;
+};
+
+/* resource handle */
+struct migr_res_handle {
+	int      rh_type;
+	int      rh_bkt;
+	uint64_t rh_units;
+};
 
 /* Per pool attached to the migrate tls(per xstream) */
 struct migrate_pool_tls {
@@ -80,8 +102,6 @@ struct migrate_pool_tls {
 	/* The current in-flight data size */
 	uint64_t                 mpt_inflight_size;
 
-	struct migr_res_manager *mpt_rmg;
-
 	/* reference count for the structure */
 	uint64_t                 mpt_refcount;
 	uint32_t		mpt_opc;
@@ -94,6 +114,11 @@ struct migrate_pool_tls {
 
 	/* migration init error */
 	int			mpt_init_err;
+
+	/* Watchdog: track progress to detect complete rebuild hang */
+	uint64_t                mpt_last_progress_obj_count; /* obj_count at last check */
+	uint64_t                mpt_last_progress_rec_count; /* rec_count at last check */
+	uint64_t                mpt_last_progress_ts;        /* time of last observed progress */
 };
 
 struct migrate_cont_hdl {