Details
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Improvement
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Resolution: Unresolved
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Major
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None
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None
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None
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3
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9223372036854775807
Description
llog_write could use llog cookie for a single record modification. In this case there is no need to process all records before an update of the record. HSM regular updates record, and cancels it after timeout only, so there could be many records at the same time. And this introduce a bottleneck for HSM.
llog subsystem requires some additional functions to do it. Also HSM need to store a whole llog record for a modification, and this leads to a different structures in memory for a HSM.
Now, Lustre operates and stores hsm_action_item, however llog_agent_req_rec include hai already. So this change is some trade of for a memory vs additional processing.