diff --git a/include/sys/arc_impl.h b/include/sys/arc_impl.h
index b1bea24ac..6134ac1f5 100644
--- a/include/sys/arc_impl.h
+++ b/include/sys/arc_impl.h
@@ -46,6 +46,10 @@ extern "C" {
  * and each of the states has two types: data and metadata.
  */
 #define	L2ARC_FEED_TYPES	4
+#define	L2ARC_MFU_META		0
+#define	L2ARC_MRU_META		1
+#define	L2ARC_MFU_DATA		2
+#define	L2ARC_MRU_DATA		3
 
 /*
  * L2ARC state and statistics for persistent marker management.
@@ -62,6 +66,12 @@ typedef struct l2arc_info {
 	boolean_t	*l2arc_sublist_busy[L2ARC_FEED_TYPES];
 	boolean_t	*l2arc_sublist_reset[L2ARC_FEED_TYPES];
 	kmutex_t	l2arc_sublist_lock;	/* protects busy/reset flags */
+	/*
+	 * Cumulative bytes scanned per pass since marker reset.
+	 * Limits how far persistent markers advance from tail
+	 * before resetting, based on % of state size.
+	 */
+	uint64_t	l2arc_ext_scanned[L2ARC_FEED_TYPES];
 	int		l2arc_next_sublist[L2ARC_FEED_TYPES]; /* round-robin */
 } l2arc_info_t;
 
diff --git a/man/man4/zfs.4 b/man/man4/zfs.4
index 97c0ac6ab..d01a36821 100644
--- a/man/man4/zfs.4
+++ b/man/man4/zfs.4
@@ -227,6 +227,12 @@ to enable caching/reading prefetches to/from L2ARC.
 .It Sy l2arc_norw Ns = Ns Sy 0 Ns | Ns 1 Pq int
 No reads during writes.
 .
+.It Sy l2arc_ext_headroom_pct Ns = Ns Sy 25 Pq u64
+Percentage of each ARC state's size that a pass may scan before
+resetting its markers to the tail.
+Lower values keep the marker closer to the tail under active workloads.
+Set to 0 to disable the depth cap.
+.
 .It Sy l2arc_write_max Ns = Ns Sy 33554432 Ns B Po 32 MiB Pc Pq u64
 Maximum write rate in bytes per second for each L2ARC device.
 Used directly during initial fill, when DWPD limiting is disabled,
diff --git a/module/zfs/arc.c b/module/zfs/arc.c
index 736faaf51..d59ce0225 100644
--- a/module/zfs/arc.c
+++ b/module/zfs/arc.c
@@ -956,6 +956,13 @@ int l2arc_exclude_special = 0;
  */
 static int l2arc_mfuonly = 0;
 
+/*
+ * Depth cap as percentage of state size.  Each pass resets its markers
+ * to tail after scanning this fraction of the state.  Keeps markers
+ * focused on the tail zone where L2ARC adds the most value.
+ */
+static uint64_t l2arc_ext_headroom_pct = 25;
+
 /*
  * L2ARC TRIM
  * l2arc_trim_ahead : A ZFS module parameter that controls how much ahead of
@@ -9083,6 +9090,8 @@ l2arc_pool_markers_init(spa_t *spa)
 			    spa->spa_l2arc_info.l2arc_markers[pass][i]);
 			multilist_sublist_unlock(mls);
 		}
+
+		spa->spa_l2arc_info.l2arc_ext_scanned[pass] = 0;
 	}
 }
 
@@ -9875,6 +9884,31 @@ l2arc_blk_fetch_done(zio_t *zio)
 	kmem_free(cb, sizeof (l2arc_read_callback_t));
 }
 
+/*
+ * Return the total size of the ARC state corresponding to the given
+ * L2ARC pass number (0..3).
+ */
+static uint64_t
+l2arc_get_state_size(int pass)
+{
+	switch (pass) {
+	case L2ARC_MFU_META:
+		return (zfs_refcount_count(
+		    &arc_mfu->arcs_size[ARC_BUFC_METADATA]));
+	case L2ARC_MRU_META:
+		return (zfs_refcount_count(
+		    &arc_mru->arcs_size[ARC_BUFC_METADATA]));
+	case L2ARC_MFU_DATA:
+		return (zfs_refcount_count(
+		    &arc_mfu->arcs_size[ARC_BUFC_DATA]));
+	case L2ARC_MRU_DATA:
+		return (zfs_refcount_count(
+		    &arc_mru->arcs_size[ARC_BUFC_DATA]));
+	default:
+		return (0);
+	}
+}
+
 /*
  * Flag all sublists for a single pass for lazy marker reset to tail.
  * Each sublist's marker will be reset when next visited by a feed thread.
@@ -9892,6 +9926,8 @@ l2arc_flag_pass_reset(spa_t *spa, int pass)
 		spa->spa_l2arc_info.l2arc_sublist_reset[pass][i] = B_TRUE;
 		multilist_sublist_unlock(mls);
 	}
+
+	spa->spa_l2arc_info.l2arc_ext_scanned[pass] = 0;
 }
 
 /*
@@ -10044,6 +10080,31 @@ l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz)
 		    (spa->spa_l2arc_info.l2arc_next_sublist[pass] + 1) %
 		    num_sublists;
 
+		/*
+		 * Depth cap: track cumulative bytes scanned per pass
+		 * and reset markers when the scan cap is reached.
+		 * Keeps the marker near the tail where L2ARC adds
+		 * the most value.
+		 */
+		if (save_position) {
+			mutex_enter(&spa->spa_l2arc_info.l2arc_sublist_lock);
+
+			spa->spa_l2arc_info.l2arc_ext_scanned[pass] +=
+			    consumed_headroom;
+
+			uint64_t state_sz = l2arc_get_state_size(pass);
+			uint64_t scan_cap =
+			    state_sz * l2arc_ext_headroom_pct / 100;
+
+			if (scan_cap > 0 &&
+			    spa->spa_l2arc_info.l2arc_ext_scanned[pass] >=
+			    scan_cap) {
+				l2arc_flag_pass_reset(spa, pass);
+			}
+
+			mutex_exit(&spa->spa_l2arc_info.l2arc_sublist_lock);
+		}
+
 		if (full == B_TRUE)
 			break;
 	}
@@ -11691,6 +11752,9 @@ ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, mfuonly, INT, ZMOD_RW,
 ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, exclude_special, INT, ZMOD_RW,
 	"Exclude dbufs on special vdevs from being cached to L2ARC if set.");
 
+ZFS_MODULE_PARAM(zfs_l2arc, l2arc_, ext_headroom_pct, U64, ZMOD_RW,
+	"Depth cap as percentage of state size for marker reset");
+
 ZFS_MODULE_PARAM_CALL(zfs_arc, zfs_arc_, lotsfree_percent, param_set_arc_int,
 	param_get_uint, ZMOD_RW, "System free memory I/O throttle in bytes");
 
diff --git a/tests/zfs-tests/include/tunables.cfg b/tests/zfs-tests/include/tunables.cfg
index 5e6959a54..4008bfe2b 100644
--- a/tests/zfs-tests/include/tunables.cfg
+++ b/tests/zfs-tests/include/tunables.cfg
@@ -47,6 +47,7 @@ INITIALIZE_VALUE		initialize_value		zfs_initialize_value
 KEEP_LOG_SPACEMAPS_AT_EXPORT	keep_log_spacemaps_at_export	zfs_keep_log_spacemaps_at_export
 LUA_MAX_MEMLIMIT		lua.max_memlimit		zfs_lua_max_memlimit
 L2ARC_DWPD_LIMIT		l2arc.dwpd_limit		l2arc_dwpd_limit
+L2ARC_EXT_HEADROOM_PCT		l2arc.ext_headroom_pct		l2arc_ext_headroom_pct
 L2ARC_MFUONLY			l2arc.mfuonly			l2arc_mfuonly
 L2ARC_NOPREFETCH		l2arc.noprefetch		l2arc_noprefetch
 L2ARC_REBUILD_BLOCKS_MIN_L2SIZE	l2arc.rebuild_blocks_min_l2size	l2arc_rebuild_blocks_min_l2size