Diffstat (limited to 'Documentation/device-mapper/dm-crypt.txt')
1 files changed, 16 insertions, 3 deletions
diff --git a/Documentation/device-mapper/dm-crypt.txt b/Documentation/device-mapper/dm-crypt.txt
index c81839b52c4d..692171fe9da0 100644
@@ -5,7 +5,7 @@ Device-Mapper's "crypt" target provides transparent encryption of block devices
using the kernel crypto API.
For a more detailed description of supported parameters see:
Parameters: <cipher> <key> <iv_offset> <device path> \
<offset> [<#opt_params> <opt_params>]
@@ -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:
- 1 allow_discards
+ 3 allow_discards same_cpu_crypt submit_from_crypt_cpus
Block discard requests (a.k.a. TRIM) are passed through the crypt device.
@@ -63,11 +63,24 @@ allow_discards
used space etc.) if the discarded blocks can be located easily on the
+ 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.
+ 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.
LUKS (Linux Unified Key Setup) is now the preferred way to set up disk
encryption with dm-crypt using the 'cryptsetup' utility, see