Slub helpers should be aware of multi-node kmem caches #233
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On a system with more than 1 nodes per cache: ``` sdb> addr nr_node_ids | deref (unsigned int)2 ``` Before this patch: ``` sdb> spl_kmem_caches -s active_memory | head 1 | spl_kmem_caches name entry_size active_objs active_memory source total_memory util ------------------- ---------- ----------- ------------- ------------------------- ------------ ---- arc_buf_hdr_t_full 328 8956159 2.7GB arc_buf_hdr_t_full[SLUB] 1.3GB 203 ``` In the output above the SLUB helpers are only looking at the first node of the kmem cache and undercount the amount of active objects in the SLUB layer and thus reporting less total_memory. As a result the SPL that explicitly tracks the counts of those allocations shows the correct number of active objects resulting to the above inconsistency where active_memory is more than total_memory and util% is more than 100%. After this patch: ``` sdb> spl_kmem_caches -s active_memory | head 1 | spl_kmem_caches name entry_size active_objs active_memory source total_memory util ------------------- ---------- ----------- ------------- ------------------------- ------------ ---- arc_buf_hdr_t_full 328 9250638 2.8GB arc_buf_hdr_t_full[SLUB] 2.8GB 99 ``` The behavior is corrected.
Codecov Report
@@ Coverage Diff @@
## master #233 +/- ##
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+ Coverage 87.29% 87.35% +0.05%
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Files 60 60
Lines 2456 2467 +11
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+ Hits 2144 2155 +11
Misses 312 312
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ahrens
approved these changes
Jul 22, 2020
grwilson
approved these changes
Jul 22, 2020
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On a system with more than 1 nodes per cache:
Before this patch:
In the output above the SLUB helpers are only looking at the first
node of the kmem cache and undercount the amount of active objects
in the SLUB layer and thus reporting less total_memory. As a result
the SPL that explicitly tracks the counts of those allocations shows
the correct number of active objects resulting to the above
inconsistency where active_memory is more than total_memory and util%
is more than 100%.
After this patch:
The behavior is corrected.