Mark Fasheh 9461104f8e scoutfs: Use LRU for locks ...

The move to dlmglue necessitating removing the old lru code. That's
fine, it didn't work anyway.

We can't drop locks in the shrinker directly, so instead we have the
shrinker put them on a workqueue where they are dropped.

The rules for the LRU are simple. Locks get a users count. Any process
that holds the lock or is in the process of acquiring the lock
increments this count. When unlock is called, the count is decremented.
We can use the value of this count to manage the LRU - scoutfs_unlock
puts locks on the LRU when the count reaches zero, lock_name_keys()
always takes them off.

If the lock is selected for reclaim, callers wanting to use the lock
will need to wait. We acheive this with a pair of flags.
SCOUTFS_LOCK_RECLAIM is used to indicate the the lock is now queued for
reclaim. Once the is ready to be destroyed, we set SCOUTFS_LOCK_DROPPED
flag, telling callers to put the lock and retry their rbtree search.

Signed-off-by: Mark Fasheh <mfasheh@versity.com>

2017-09-08 09:57:04 -07:00

kmod

scoutfs: Use LRU for locks

2017-09-08 09:57:04 -07:00

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