X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=blobdiff_plain;f=block%2Fbfq-iosched.c;h=0319d63398223420c3b99e537c426c4a0df2b953;hb=d7e8d149c5f3774fd8d422364c38afb69501ccb0;hp=b33be928d164fef34f5d2f00863d9034e38ef1a2;hpb=57f1c3caf5137d4493fcd1d07c3ae4a5636f4949;p=linux.git

diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
index b33be928d164..0319d6339822 100644
--- a/block/bfq-iosched.c
+++ b/block/bfq-iosched.c
@@ -2016,7 +2016,7 @@ static void bfq_add_request(struct request *rq)
 		     (bfqq->last_serv_time_ns > 0 &&
 		      bfqd->rqs_injected && bfqd->rq_in_driver > 0)) &&
 		    time_is_before_eq_jiffies(bfqq->decrease_time_jif +
-					      msecs_to_jiffies(100))) {
+					      msecs_to_jiffies(10))) {
 			bfqd->last_empty_occupied_ns = ktime_get_ns();
 			/*
 			 * Start the state machine for measuring the
@@ -2025,7 +2025,21 @@ static void bfq_add_request(struct request *rq)
 			 * be set when rq will be dispatched.
 			 */
 			bfqd->wait_dispatch = true;
-			bfqd->rqs_injected = false;
+			/*
+			 * If there is no I/O in service in the drive,
+			 * then possible injection occurred before the
+			 * arrival of rq will not affect the total
+			 * service time of rq. So the injection limit
+			 * must not be updated as a function of such
+			 * total service time, unless new injection
+			 * occurs before rq is completed. To have the
+			 * injection limit updated only in the latter
+			 * case, reset rqs_injected here (rqs_injected
+			 * will be set in case injection is performed
+			 * on bfqq before rq is completed).
+			 */
+			if (bfqd->rq_in_driver == 0)
+				bfqd->rqs_injected = false;
 		}
 	}
 
@@ -5784,14 +5798,14 @@ static void bfq_update_inject_limit(struct bfq_data *bfqd,
 	u64 tot_time_ns = ktime_get_ns() - bfqd->last_empty_occupied_ns;
 	unsigned int old_limit = bfqq->inject_limit;
 
-	if (bfqq->last_serv_time_ns > 0) {
+	if (bfqq->last_serv_time_ns > 0 && bfqd->rqs_injected) {
 		u64 threshold = (bfqq->last_serv_time_ns * 3)>>1;
 
 		if (tot_time_ns >= threshold && old_limit > 0) {
 			bfqq->inject_limit--;
 			bfqq->decrease_time_jif = jiffies;
 		} else if (tot_time_ns < threshold &&
-			   old_limit < bfqd->max_rq_in_driver<<1)
+			   old_limit <= bfqd->max_rq_in_driver)
 			bfqq->inject_limit++;
 	}
 
@@ -5809,12 +5823,14 @@ static void bfq_update_inject_limit(struct bfq_data *bfqd,
 	 */
 	if ((bfqq->last_serv_time_ns == 0 && bfqd->rq_in_driver == 1) ||
 	    tot_time_ns < bfqq->last_serv_time_ns) {
+		if (bfqq->last_serv_time_ns == 0) {
+			/*
+			 * Now we certainly have a base value: make sure we
+			 * start trying injection.
+			 */
+			bfqq->inject_limit = max_t(unsigned int, 1, old_limit);
+		}
 		bfqq->last_serv_time_ns = tot_time_ns;
-		/*
-		 * Now we certainly have a base value: make sure we
-		 * start trying injection.
-		 */
-		bfqq->inject_limit = max_t(unsigned int, 1, old_limit);
 	} else if (!bfqd->rqs_injected && bfqd->rq_in_driver == 1)
 		/*
 		 * No I/O injected and no request still in service in
@@ -5830,6 +5846,7 @@ static void bfq_update_inject_limit(struct bfq_data *bfqd,
 
 	/* update complete, not waiting for any request completion any longer */
 	bfqd->waited_rq = NULL;
+	bfqd->rqs_injected = false;
 }
 
 /*