Eviction changes allowing to evict (remap) cachelines while
holding hash bucket write lock instead of global metadata
write lock.
As eviction (replacement) is now tightly coupled with request,
each request uses eviction size equal to number of its
unmapped cachelines.
Evicting without global metadata write lock is possible
thanks to the fact that remaping is always performed
while exclusively holding cacheline (read or write) lock.
So for a cacheline on LRU list we acquire cacheline lock,
safely resolve hash and consequently write-lock hash bucket.
Since cacheline lock is acquired under hash bucket (everywhere
except for new eviction implementation), we are certain that
noone acquires cacheline lock behind our back. Concurrent
eviction threads are eliminated by holding eviction list
lock for the duration of critial locking operations.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
If an ioclass is pinned but it exceeded its occupancy limit, it should be
evicted anyway.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Overflown partitions now have precedence over others during
eviction, regardless of IO class priorities.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Min and max values, keept as an explicit number of cachelines, are tightly
coupled with particular cache. This might lead to errors and mismatches after
reattaching cache of different size.
To prevent those errors, min and max should be calculated dynamically.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
If partition's occupancy limit is reached, cachelines should be evicted from
request's target partition.
Information whether particular partition eviction should be triggered is
carried as a flag by request which triggered eviction.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
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>
Promotion policy is supposed to perform ALRU noise filtering by
eliminating one-hit wonders being added to cache and polluting it.
Signed-off-by: Jan Musial <jan.musial@intel.com>
- Queue allocation is now separated from starting cache.
- Queue can be created and destroyed in runtime.
- All queue ops accept queue handle instead of queue id.
- Cache stores queues as list instead of array.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
