OpenZFS 7606 - dmu_objset_find_dp() takes a long time while importing… #5662
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@gmelikov, thanks for your PR! By analyzing the history of the files in this pull request, we identified @behlendorf, @ahrens and @nedbass to be potential reviewers. |
… pool Authored by: Matthew Ahrens <mahrens@delphix.com> Reviewed by: Steve Gonczi <steve.gonczi@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Prashanth Sreenivasa <prashksp@gmail.com> Ported-by: George Melikov <mail@gmelikov.ru> OpenZFS-issue: https://www.illumos.org/issues/7606 OpenZFS-commit: openzfs/openzfs@cac6bab When importing a pool with a large number of filesystems within the same parent filesystem, we see that dmu_objset_find_dp() takes a long time. It is called from 3 places: spa_check_logs(), spa_ld_claim_log_blocks(), and spa_load_verify(). There are several ways to improve performance here: 1. We don't really need to do spa_check_logs() or spa_ld_claim_log_blocks() if the pool was closed cleanly. 2. spa_load_verify() uses dmu_objset_find_dp() to check that no datasets have too long of names. 3. dmu_objset_find_dp() is slow because it's doing zap_value_search() (which is O(N sibling datasets)) to determine the name of each dsl_dir when it's opened. In this case we actually know the name when we are opening it, so we can provide it and avoid the lookup. This change implements fix #3 from the above list; i.e. make dmu_objset_find_dp() provide the name of the dataset so that we don't have to search for it.
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… pool
When importing a pool with a large number of filesystems within the same
parent filesystem, we see that dmu_objset_find_dp() takes a long time.
It is called from 3 places: spa_check_logs(), spa_ld_claim_log_blocks(),
and spa_load_verify().
There are several ways to improve performance here:
1. We don't really need to do spa_check_logs() or
spa_ld_claim_log_blocks() if the pool was closed cleanly.
2. spa_load_verify() uses dmu_objset_find_dp() to check that no
datasets have too long of names.
3. dmu_objset_find_dp() is slow because it's doing
zap_value_search() (which is O(N sibling datasets)) to determine
the name of each dsl_dir when it's opened. In this case we
actually know the name when we are opening it, so we can provide
it and avoid the lookup.
This change implements fix openzfs#3 from the above list; i.e. make
dmu_objset_find_dp() provide the name of the dataset so that we don't
have to search for it.
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prashanth Sreenivasa <prashksp@gmail.com>
Reviewed-by: David Quigley <david.quigley@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7606
OpenZFS-commit: openzfs/openzfs@cac6bab
Closes openzfs#5662
wli5
pushed a commit
to wli5/zfs
that referenced
this pull request
Feb 28, 2017
… pool
When importing a pool with a large number of filesystems within the same
parent filesystem, we see that dmu_objset_find_dp() takes a long time.
It is called from 3 places: spa_check_logs(), spa_ld_claim_log_blocks(),
and spa_load_verify().
There are several ways to improve performance here:
1. We don't really need to do spa_check_logs() or
spa_ld_claim_log_blocks() if the pool was closed cleanly.
2. spa_load_verify() uses dmu_objset_find_dp() to check that no
datasets have too long of names.
3. dmu_objset_find_dp() is slow because it's doing
zap_value_search() (which is O(N sibling datasets)) to determine
the name of each dsl_dir when it's opened. In this case we
actually know the name when we are opening it, so we can provide
it and avoid the lookup.
This change implements fix openzfs#3 from the above list; i.e. make
dmu_objset_find_dp() provide the name of the dataset so that we don't
have to search for it.
Authored by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Steve Gonczi <steve.gonczi@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Prashanth Sreenivasa <prashksp@gmail.com>
Reviewed-by: David Quigley <david.quigley@intel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Ported-by: George Melikov <mail@gmelikov.ru>
OpenZFS-issue: https://www.illumos.org/issues/7606
OpenZFS-commit: openzfs/openzfs@cac6bab
Closes openzfs#5662
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… pool
Authored by: Matthew Ahrens mahrens@delphix.com
Reviewed by: Steve Gonczi steve.gonczi@delphix.com
Reviewed by: George Wilson george.wilson@delphix.com
Reviewed by: Prashanth Sreenivasa prashksp@gmail.com
Ported-by: George Melikov mail@gmelikov.ru
OpenZFS-issue: https://www.illumos.org/issues/7606
OpenZFS-commit: openzfs/openzfs@cac6bab