This is useful when reference counter is initialized in non-zeroed
memory (or assuming atomic variable is not properly initialized by
memseting to zero).
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
In order to synchronize management operations with I/O OCF
maintains in-flight request counters. For example such ref
counters are used during ocf_mngt_detach to drain requests
accessing cache metadata (cache requests counter) and in
ocf_mngt_flush where we wait for outstanding requests sent
in write back mode (dirty requests counter).
Typically I/O threads increment cache/dirty counter when
creating request and decrement counter on request completion.
Management thread sets atomic variable to signal the start of
management operation. I/O threads react to this by changing
I/O requests mode so that the cache/dirty reference counter
is not incremented. As a result reference counter keeps getting
decremented. Management thread waits for the counter to drop to 0
and proceeds with management operation with assumption that no
cache/dirty requests are in progress.
This patch introduces a handy utility for requests reference
counting logic. ocf_refcnt_inc / dec are used to increment/
decrement counter. ocf_refcnt_freeze() makes subsequent
ocf_refcnt_inc() calls to return false, indicating that counter
cannot be incremented at this moment. ocf_refcnt_register_zero_cb
can be used to asynchronously wait for counter to drop to 0.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
For flush/purge entry points to be fully asynchronous we still
need to rework flush mutex and waiting for outstanding dirty
requests.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Send cleaner IOs with appropriate queue set
This solves the issue of bottom adapter getting NULL in io->io_queue
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
This allows to reuse same step functions giving them different parameters
on each step.
Additionally move pipeline to utils, to make it accessible to other
subsystems of OCF (e.g. metadata).
Signed-off-by: Robert Baldyga <robert.baldyga@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>
NOTE: This patch only changes API that pretends to be asynchronous.
Most of management operations are still performed synchronously.
The real asynchronism will be introduced in the next patches.
Signed-off-by: Robert Baldyga <robert.baldyga@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>
Propagate id of ocf_queue where it is possible
This resolves the issue of
bottom adapter always getting an ocf_io with io_queue = 0,
no matter from which queue function to bottom adapter was called
Signed-off-by: Vitaliy Mysak <vitaliy.mysak@intel.com>
