ae52efc673
The expensive transfer scan now scans a whole set of remotes in one pass. So at startup, or when network comes up, it will run only once. Note that this can result in transfers from/to higher cost remotes being queued before other transfers of other content from/to lower cost remotes. Before, low cost remotes were scanned first and all their transfers came first. When multiple transfers are queued for a key, the lower cost ones are still queued first. However, this could result in transfers from slow remotes running for a long time while transfers of other data from faster remotes waits. I expect to make the transfer queue smarter about ordering and/or make it allow multiple transfers at a time, which should eliminate this annoyance. (Also, it was already possible to get into that situation, for example if the network was up, lots of transfers from slow remotes might be queued, and then a disk is mounted and its faster transfers have to wait.) Also note that this means I don't need to improve the code in Assistant.Sync that currently checks if any of the reconnected remotes have diverged, and if so, queues scans of all of them. That had been very innefficient, but now doesn't matter.
48 lines
1.4 KiB
Haskell
48 lines
1.4 KiB
Haskell
{- git-annex assistant remotes needing scanning
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-
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- Copyright 2012 Joey Hess <joey@kitenet.net>
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-
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- Licensed under the GNU GPL version 3 or higher.
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-}
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module Assistant.ScanRemotes where
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import Common.Annex
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import qualified Types.Remote as Remote
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import Data.Function
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import Control.Concurrent.STM
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import qualified Data.Map as M
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data ScanInfo = ScanInfo
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{ scanPriority :: Int
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, fullScan :: Bool
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}
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type ScanRemoteMap = TMVar (M.Map Remote ScanInfo)
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{- The TMVar starts empty, and is left empty when there are no remotes
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- to scan. -}
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newScanRemoteMap :: IO ScanRemoteMap
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newScanRemoteMap = atomically newEmptyTMVar
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{- Blocks until there is a remote or remotes that need to be scanned.
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-
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- The list has higher priority remotes listed first. -}
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getScanRemote :: ScanRemoteMap -> IO [(Remote, ScanInfo)]
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getScanRemote v = atomically $
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reverse . sortBy (compare `on` scanPriority . snd) . M.toList
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<$> takeTMVar v
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{- Adds new remotes that need scanning. -}
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addScanRemotes :: ScanRemoteMap -> Bool -> [Remote] -> IO ()
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addScanRemotes _ _ [] = noop
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addScanRemotes v full rs = atomically $ do
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m <- fromMaybe M.empty <$> tryTakeTMVar v
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putTMVar v $ M.unionWith merge (M.fromList $ zip rs (map info rs)) m
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where
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info r = ScanInfo (-1 * Remote.cost r) full
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merge x y = ScanInfo
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{ scanPriority = max (scanPriority x) (scanPriority y)
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, fullScan = fullScan x || fullScan y
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}
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