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author | Mikulas Patocka <mpatocka@redhat.com> | 2015-02-13 08:25:59 -0500 |
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committer | Mike Snitzer <snitzer@redhat.com> | 2015-02-16 11:11:14 -0500 |
commit | dc2676210c425ee8e5cb1bec5bc84d004ddf4179 (patch) | |
tree | 2d38e1d74895e7cf419a0408805ed73673d69425 /Documentation/device-mapper | |
parent | 94f5e0243c48aa01441c987743dc468e2d6eaca2 (diff) | |
download | linux-dc2676210c425ee8e5cb1bec5bc84d004ddf4179.tar.bz2 |
dm crypt: offload writes to thread
Submitting write bios directly in the encryption thread caused serious
performance degradation. On a multiprocessor machine, encryption requests
finish in a different order than they were submitted. Consequently, write
requests would be submitted in a different order and it could cause severe
performance degradation.
Move the submission of write requests to a separate thread so that the
requests can be sorted before submitting. But this commit improves
dm-crypt performance even without having dm-crypt perform request
sorting (in particular it enables IO schedulers like CFQ to sort more
effectively).
Note: it is required that a previous commit ("dm crypt: don't allocate
pages for a partial request") be applied before applying this patch.
Otherwise, this commit could introduce a crash.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'Documentation/device-mapper')
0 files changed, 0 insertions, 0 deletions