diff options
| -rw-r--r-- | Documentation/device-mapper/dm-crypt.txt | 10 | ||||
| -rw-r--r-- | drivers/md/dm-crypt.c | 16 |
2 files changed, 23 insertions, 3 deletions
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: <cipher> <key> <iv_offset> <device path> \ 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 d216a99dabf7..d97f9eaa9145 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. @@ -1245,6 +1246,11 @@ 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); @@ -1699,7 +1705,7 @@ 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) { @@ -1807,6 +1813,9 @@ 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; @@ -1910,12 +1919,15 @@ 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; |