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https://issues.apache.org/jira/browse/IGNITE-2876?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Vladimir Ozerov closed IGNITE-2876.
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> IGFS: System pool starvation is possible during data block write.
> -----------------------------------------------------------------
>
> Key: IGNITE-2876
> URL: https://issues.apache.org/jira/browse/IGNITE-2876
> Project: Ignite
> Issue Type: Bug
> Components: IGFS
> Affects Versions: 1.5.0.final
> Reporter: Vladimir Ozerov
> Assignee: Vladimir Ozerov
> Priority: Critical
> Fix For: 1.6
>
>
> *Problem*
> IGFS has a set of messages to exchange data and signal events between nodes.
> These are:
> - {{IgfsAckMessage}}
> - {{IgfsBlocksMessage}}
> - {{IgfsDeleteMessage}}
> - {{IgfsFragmentizerRequest}}
> - {{IgfsFragmentizerResponse}}
> Currently these messages are processed in a system pool which is wrong and
> may lead to starvation, deadlocks and incorrect behavior.
> Several examples:
> 1) {{IgfsBlocksMessage}} handling logic performs "Cache.putAsync" operation.
> This operation involves acquiring of semaphore permit. This semaphore, in
> turn, can only be released from another thread in the same system pool. As
> such, all system pool threads could hang on permit acquire forever.
> 2) In case file system size is exceeded, the same message waits for some time
> in hope that free space in cache will appear. However, if all system pool
> threads waits for this point, concurrent block removal cannot proceed, so
> these threads are doomed to receive {{IgfsOutOfSpaceException}} irrespective
> of whether they wait or not.
> *Solution*
> 1) Introduce new IO policy for IGFS (see {{GridIoPolicy}}).
> 2) Force all IGFS message to be processed with this policy. No backward
> compatibility is needed.
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