Global free cacheline list is divided into a set of freelists, one
per execution context. When attempting to map addres to cache, first
the freelist for current execution context is considered (fast path).
If current execution context freelist is empty (fast path failure),
mapping function attempts to get freelist from other execution context
list (slow path).
The purpose of this change is improve concurrency in freelist access.
It is part of fine granularity metadata lock implementation.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
NOTE: This is still not the real asynchronism. Metadata interfaces
are still not fully asynchronous.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
- Add cache trylock and read trylock functions.
- Introduce new error code -OCF_ERR_NO_LOCK.
- Change trylock functions in env to return this code in case of
lock contention.
[ENV CHANGES REQUIRED]
Following functions should return 0 on success or -OCF_ERR_NO_LOCK
in case of lock contention:
- env_mutex_trylock()
- env_rwsem_up_read_trylock()
- env_rwsem_up_write_trylock()
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
