diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2015-02-13 16:27:08 +0300 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-02-16 19:11:15 +0300 |
| commit | 0f5d8e6ee758f7023e4353cca75d785b2d4f6abe (patch) | |
| tree | 836041a22c3b5f5eb6151f27b7b0dec1714ac5fd /drivers/md | |
| parent | dc2676210c425ee8e5cb1bec5bc84d004ddf4179 (diff) | |
| download | linux-0f5d8e6ee758f7023e4353cca75d785b2d4f6abe.tar.xz | |
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 <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm-crypt.c | 16 |
1 files changed, 14 insertions, 2 deletions
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; |