diff --git a/kernel/mars_bio.c b/kernel/mars_bio.c
index 69582e1b..80ddbcb5 100644
--- a/kernel/mars_bio.c
+++ b/kernel/mars_bio.c
@@ -434,14 +434,19 @@ void _bio_ref_io(struct bio_output *output, struct mref_object *mref, bool cork)
 	bio_get(bio);
 
 	rw = mref->ref_rw & 1;
-	if (brick->do_noidle && !cork) {
+	if (cork) {
 // adapt to different kernel versions (TBD: improve)
+#ifdef REQ_IDLE
+		rw |= REQ_IDLE;
+#else /* sorry this went clumsy over time, adaptation to _any_ kernel is a hell */
+	} else {
 #if defined(BIO_RW_RQ_MASK) || defined(BIO_FLUSH)
 		rw |= (1 << BIO_RW_NOIDLE);
 #elif defined(REQ_NOIDLE)
 		rw |= REQ_NOIDLE;
 #else
 #warning Cannot control the NOIDLE flag
+#endif
 #endif
 	}
 	if (!mref->ref_skip_sync) {
diff --git a/kernel/mars_bio.h b/kernel/mars_bio.h
index 1ffe41c6..b32199e4 100644
--- a/kernel/mars_bio.h
+++ b/kernel/mars_bio.h
@@ -61,7 +61,6 @@ struct bio_brick {
 	int ra_pages;
 	int bg_threshold;
 	int bg_maxfly;
-	bool do_noidle;
 	bool do_sync;
 	bool do_unplug;
 	// readonly
diff --git a/kernel/mars_server.c b/kernel/mars_server.c
index 2aafecbb..d51fbaf9 100644
--- a/kernel/mars_server.c
+++ b/kernel/mars_server.c
@@ -354,7 +354,6 @@ int _set_server_bio_params(struct mars_brick *_brick, void *private)
 	}
 	bio_brick = (void*)_brick;
 	bio_brick->ra_pages = 0;
-	bio_brick->do_noidle = true;
 	bio_brick->do_sync = true;
 	bio_brick->do_unplug = true;
 	MARS_INF("name = '%s' path = '%s'\n", _brick->brick_name, _brick->brick_path);
diff --git a/kernel/sy_old/mars_main.c b/kernel/sy_old/mars_main.c
index f5c47da0..ed349e9e 100644
--- a/kernel/sy_old/mars_main.c
+++ b/kernel/sy_old/mars_main.c
@@ -698,7 +698,6 @@ int mars_mem_gb = 16;
 
 #define BIO_READAHEAD 0
 //#define BIO_READAHEAD 1
-#define BIO_NOIDLE true
 #define BIO_SYNC true
 #define BIO_UNPLUG true
 
@@ -816,7 +815,6 @@ int _set_bio_params(struct mars_brick *_brick, void *private)
 	}
 	bio_brick = (void*)_brick;
 	bio_brick->ra_pages = BIO_READAHEAD;
-	bio_brick->do_noidle = BIO_NOIDLE;
 	bio_brick->do_sync = BIO_SYNC;
 	bio_brick->do_unplug = BIO_UNPLUG;
 	bio_brick->killme = true;