From f3396c58fd8442850e759843457d78b6ec3a9589 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 13 Feb 2015 08:23:09 -0500 Subject: dm crypt: use unbound workqueue for request processing Use unbound workqueue by default so that work is automatically balanced between available CPUs. The original behavior of encrypting using the same cpu that IO was submitted on can still be enabled by setting the optional 'same_cpu_crypt' table argument. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- Documentation/device-mapper/dm-crypt.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt index c81839b52c4d..571f24ffc91c 100644 --- a/Documentation/device-mapper/dm-crypt.txt +++ b/Documentation/device-mapper/dm-crypt.txt @@ -51,7 +51,7 @@ Parameters: \ Otherwise #opt_params is the number of following arguments. Example of optional parameters section: - 1 allow_discards + 2 allow_discards same_cpu_crypt allow_discards Block discard requests (a.k.a. TRIM) are passed through the crypt device. @@ -63,6 +63,11 @@ allow_discards used space etc.) if the discarded blocks can be located easily on the device later. +same_cpu_crypt + Perform encryption using the same cpu that IO was submitted on. + The default is to use an unbound workqueue so that encryption work + is automatically balanced between available CPUs. + Example scripts =============== LUKS (Linux Unified Key Setup) is now the preferred way to set up disk -- cgit v1.2.3-59-g8ed1b From 0f5d8e6ee758f7023e4353cca75d785b2d4f6abe Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Fri, 13 Feb 2015 08:27:08 -0500 Subject: dm crypt: add 'submit_from_crypt_cpus' option Make it possible to disable offloading writes by setting the optional 'submit_from_crypt_cpus' table argument. There are some situations where offloading write bios from the encryption threads to a single thread degrades performance significantly. The default is to offload write bios to the same thread because it benefits CFQ to have writes submitted using the same IO context. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- Documentation/device-mapper/dm-crypt.txt | 10 +++++++++- drivers/md/dm-crypt.c | 16 ++++++++++++++-- 2 files changed, 23 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt index 571f24ffc91c..ad697781f9ac 100644 --- a/Documentation/device-mapper/dm-crypt.txt +++ b/Documentation/device-mapper/dm-crypt.txt @@ -51,7 +51,7 @@ Parameters: \ Otherwise #opt_params is the number of following arguments. Example of optional parameters section: - 2 allow_discards same_cpu_crypt + 3 allow_discards same_cpu_crypt submit_from_crypt_cpus allow_discards Block discard requests (a.k.a. TRIM) are passed through the crypt device. @@ -68,6 +68,14 @@ same_cpu_crypt The default is to use an unbound workqueue so that encryption work is automatically balanced between available CPUs. +submit_from_crypt_cpus + Disable offloading writes to a separate thread after encryption. + There are some situations where offloading write bios from the + encryption threads to a single thread degrades performance + significantly. The default is to offload write bios to the same + thread because it benefits CFQ to have writes submitted using the + same context. + Example scripts =============== LUKS (Linux Unified Key Setup) is now the preferred way to set up disk diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 8c0e36b1d0ed..4519a7c0098c 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -110,7 +110,8 @@ struct iv_tcw_private { * Crypt: maps a linear range of a block device * and encrypts / decrypts at the same time. */ -enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, DM_CRYPT_SAME_CPU }; +enum flags { DM_CRYPT_SUSPENDED, DM_CRYPT_KEY_VALID, + DM_CRYPT_SAME_CPU, DM_CRYPT_NO_OFFLOAD }; /* * The fields in here must be read only after initialization. @@ -1239,6 +1240,11 @@ static void kcryptd_crypt_write_io_submit(struct dm_crypt_io *io, int async) clone->bi_iter.bi_sector = cc->start + io->sector; + if (likely(!async) && test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) { + generic_make_request(clone); + return; + } + spin_lock_irqsave(&cc->write_thread_wait.lock, flags); list_add_tail(&io->list, &cc->write_thread_list); wake_up_locked(&cc->write_thread_wait); @@ -1693,7 +1699,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) char dummy; static struct dm_arg _args[] = { - {0, 2, "Invalid number of feature args"}, + {0, 3, "Invalid number of feature args"}, }; if (argc < 5) { @@ -1802,6 +1808,9 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) else if (!strcasecmp(opt_string, "same_cpu_crypt")) set_bit(DM_CRYPT_SAME_CPU, &cc->flags); + else if (!strcasecmp(opt_string, "submit_from_crypt_cpus")) + set_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); + else { ti->error = "Invalid feature arguments"; goto bad; @@ -1905,12 +1914,15 @@ static void crypt_status(struct dm_target *ti, status_type_t type, num_feature_args += !!ti->num_discard_bios; num_feature_args += test_bit(DM_CRYPT_SAME_CPU, &cc->flags); + num_feature_args += test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags); if (num_feature_args) { DMEMIT(" %d", num_feature_args); if (ti->num_discard_bios) DMEMIT(" allow_discards"); if (test_bit(DM_CRYPT_SAME_CPU, &cc->flags)) DMEMIT(" same_cpu_crypt"); + if (test_bit(DM_CRYPT_NO_OFFLOAD, &cc->flags)) + DMEMIT(" submit_from_crypt_cpus"); } break; -- cgit v1.2.3-59-g8ed1b