path: root/rescue
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authorJosh Paetzel <jpaetzel@FreeBSD.org>2017-04-27 15:10:45 +0000
committerJosh Paetzel <jpaetzel@FreeBSD.org>2017-04-27 15:10:45 +0000
commitfa88c7891454ff938aef617af1325a16ed4ca92b (patch)
treeb34ea47707dbcdc90597aa5642245fdcdafbab2b /rescue
parent4aa92fe2f385fa66a86878dd38e29cde6c28ece7 (diff)
parentcdeb4e5f0896ac66ab0f2e5c8d5f674aa79a5f94 (diff)
MFV 316895
7606 dmu_objset_find_dp() takes a long time while importing pool illumos/illumos-gate@7588687e6ba67c47bf7c9805086dec4a97fcac7b https://github.com/illumos/illumos-gate/commit/7588687e6ba67c47bf7c9805086dec4a97fcac7b https://www.illumos.org/issues/7606 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. Reviewed by: Steve Gonczi <steve.gonczi@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Prashanth Sreenivasa <prashksp@gmail.com> Approved by: Gordon Ross <gordon.w.ross@gmail.com> Author: Matthew Ahrens <mahrens@delphix.com>
Notes: svn path=/head/; revision=317507
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