[skip changelog] pinmfs: mitigate slow mfs writes when it triggers #10623
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This mitigates slow mfs writes when the pinmfs daemon calls mfs.RootNode() When writing lots of files to MFS, this call triggers a mfs directory cache sync operations. The cache grows forever and is unbounded. The more files added to a directory, the longer it takes. In the meantime, writing to mfs is locked. The pinmfs, even when no remote pinning services are configured, will trigger this issue. When RootNode() takes more than 30 seconds, the issue will be triggered continuously causing a write-deadlock onto MFS. This commit does not fix the fact that if you write 1M items into an MFS directory, the first time that the directory is traversed it will still have to sync those 1M items. It does at least prevent writes from stalling after about ~6000 items.
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If we take ipfs/boxo#751, we will need something that triggers Flushing regularly or a way to keep the cache size under control before it is too big. |
gammazero
approved these changes
Dec 13, 2024
This was referenced Dec 16, 2024
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This mitigates slow mfs writes when the pinmfs daemon calls mfs.RootNode()
When writing lots of files to MFS, this call triggers a mfs directory cache sync operations. The cache grows forever and is unbounded. The more files added to a directory, the longer it takes. In the meantime, writing to mfs is locked.
The pinmfs, even when no remote pinning services are configured, will trigger this issue. When RootNode() takes more than 30 seconds, the issue will be triggered continuously causing a write-deadlock onto MFS.
This commit does not fix the fact that if you write 1M items into an MFS directory, the first time that the directory is traversed it will still have to sync those 1M items. It does at least prevent writes from stalling after about ~6000 items.