From: Tim Murray <timmurray@google.com>
Date: Wed, 20 Jan 2016 00:33:27 +0000 (-0800)
Subject: ANDROID: dm-crypt: run in a WQ_HIGHPRI workqueue
X-Git-Tag: firefly_0821_release~2958^2~23
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=dc874623048d1ffae1ba50188f623dbe7551c124;p=firefly-linux-kernel-4.4.55.git

ANDROID: dm-crypt: run in a WQ_HIGHPRI workqueue

(cherry pick from commit ad3ac5180979e5dd1f84e4a807f76fb9fb19f814)

Running dm-crypt in a standard workqueue results in IO competing for CPU
time with standard user apps, which can lead to pipeline bubbles and
seriously degraded performance. Move to a WQ_HIGHPRI workqueue to
protect against that.

Signed-off-by: Tim Murray <timmurray@google.com>
Bug: 25392275
Change-Id: I2828587c754a7c2cafdd78b3323b9896cb8cd4e7
---

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 3147c8d09ea8..e85bcae50f65 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1864,16 +1864,24 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 	}
 
 	ret = -ENOMEM;
-	cc->io_queue = alloc_workqueue("kcryptd_io", WQ_MEM_RECLAIM, 1);
+	cc->io_queue = alloc_workqueue("kcryptd_io",
+				       WQ_HIGHPRI |
+				       WQ_MEM_RECLAIM,
+				       1);
 	if (!cc->io_queue) {
 		ti->error = "Couldn't create kcryptd io queue";
 		goto bad;
 	}
 
 	if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
-		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM, 1);
+		cc->crypt_queue = alloc_workqueue("kcryptd",
+						  WQ_HIGHPRI |
+						  WQ_MEM_RECLAIM, 1);
 	else
-		cc->crypt_queue = alloc_workqueue("kcryptd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
+		cc->crypt_queue = alloc_workqueue("kcryptd",
+						  WQ_HIGHPRI |
+						  WQ_MEM_RECLAIM |
+						  WQ_UNBOUND,
 						  num_online_cpus());
 	if (!cc->crypt_queue) {
 		ti->error = "Couldn't create kcryptd queue";