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 3147c8d09ea84a0a76d0fd7ead35931a89e29aed..e85bcae50f65f68c2035efcbb328006d1bf45bb7 100644 (file)
--- 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";