From: yangerkun <yangerkun@xxxxxxxxxx>
Once there is a heavy IO load, so many encrypt/decrypt work will occupy
all of the cpu, which may lead the poor performance for other service.
So the idea like 'a2b8b2d97567 ("dm crypt: export sysfs of kcryptd
workqueue")' said seems necessary. We can export "kcryptd" workqueue
sysfs, the entry like cpumask/max_active and so on can help us to limit
the usage for encrypt/decrypt work.
However, that commit does not consider the reload table will call .ctr
before .dtr, so the reload for dm-crypt will fail since the same sysfs
problem, and then we revert that commit('48b0777cd93d ("Revert "dm
crypt: export sysfs of kcryptd workqueue"")').
Actually, what we should do is give a unique name once we try reload
table, we can use ida to fix the problem.
Signed-off-by: yangerkun <yangerkun@xxxxxxxxxx>
---
drivers/md/dm-crypt.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)
v1->v2:
rewrite the commit msg
v2->v3:
no logical change, just rebase to latest linux kernel
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 1dc6227d353e..f4678eb71322 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -47,6 +47,8 @@
#define DM_MSG_PREFIX "crypt"
+static DEFINE_IDA(crypt_queue_ida);
+
/*
* context holding the current state of a multi-part conversion
*/
@@ -182,6 +184,7 @@ struct crypt_config {
struct crypto_aead **tfms_aead;
} cipher_tfm;
unsigned int tfms_count;
+ int crypt_queue_id;
unsigned long cipher_flags;
/*
@@ -2735,6 +2738,9 @@ static void crypt_dtr(struct dm_target *ti)
if (cc->crypt_queue)
destroy_workqueue(cc->crypt_queue);
+ if (cc->crypt_queue_id)
+ ida_free(&crypt_queue_ida, cc->crypt_queue_id);
+
crypt_free_tfms(cc);
bioset_exit(&cc->bs);
@@ -3371,12 +3377,24 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
}
if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags))
- cc->crypt_queue = alloc_workqueue("kcryptd/%s", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM,
+ cc->crypt_queue = alloc_workqueue("kcryptd-%s", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM,
1, devname);
- else
- cc->crypt_queue = alloc_workqueue("kcryptd/%s",
- WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND,
- num_online_cpus(), devname);
+ else {
+ int id = ida_alloc_min(&crypt_queue_ida, 1, GFP_KERNEL);
+
+ if (id < 0) {
+ ti->error = "Couldn't get kcryptd queue id";
+ ret = id;
+ goto bad;
+ }
+
+ cc->crypt_queue_id = id;
+ cc->crypt_queue = alloc_workqueue("kcryptd-%s-%d",
+ WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM |
+ WQ_UNBOUND | WQ_SYSFS,
+ num_online_cpus(), devname, id);
+ }
+
if (!cc->crypt_queue) {
ti->error = "Couldn't create kcryptd queue";
goto bad;
