WA write must follow follow the same two-pass pattern
as WI does. This change modifies WA engine to default to
WI in case of any miss (either partial or full), not only
partial miss.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Add second pass of write invalidate. It is necessary only
if concurrent I/O had inserted target LBAs to cache after
WI request did traversation. These LBAs might have been
written by WI request behind the concurrent I/O's back,
resulting in making these sectors effectively invalid.
In this case we must update these sectors' metadata to
reflect this. However we won't know about this after we
traverse the request again - hence calling ocf_write_wi
again with req->wi_second_pass set to indicate that this
is the second pass (core write should be skipped).
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
ocf_engine_push_req_(front|back) must not dereference req
pointer after putting the request on queue list and unlocking
the queue. At this point handler interface may asynchronously
pick up the request, handle it and deallocate.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
There is no need to constantly hold metadata global lock
during collecting cachelines to clean. Since we are past
freezing dirty request counter, we know for sure that the
number of dirty cache lines will not increase. So the worst
case is when the loop realxes and releases the lock,
a concurent IO to CAS is serviced in WT mode, possibly
inserting and/or evicting cachelines. This does not interfere
with scanning for dirty cachelines. And the lower layer will
handle synchronization with concurrent I/O by acquiring
asynchronous read lock on each cleaned cacheline.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
In current implementation in case of fast media flushning
container may starve all concurrent containers flushing
due to continous rescheduling of offender requests to the
front of I/O queue. Pushing request to the back of IO
queue ensures FIFO handling and removes possibility of
starvation.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Lower layer is prepared to handle used cachelines by
acquiring asynchronus read lock. It is very likely that
by the time the cacheline is actually cleaned its lock
state changes. So checking the lock at the moment of
constructing dirty cachelines list makes little sense.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Moving _ocf_mngt_flush_containers outside global metadata
critical section. All this function does is sort core lines
and add queue request.
This fixes stalls reported by Linux scheduler due to
IO threads waiting on global metadata RW semaprhore for
several minutes.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
a_req is allocated using env_vmalloc() so we need to free it
using env_vfree(), not env_free().
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Discard handling splits large request into several steps.
However the actual size of request map for discard was
determined based on original request size, not step request
size, resulting in waste of memory and allocations > 4K.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
512K is the maximum request size for which request map
fits into one page (4K) regardless of cacheline size.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
In case of cleaning metadata used to be flushed only when status of whole cache
line changed to clean.
This patch ensures that metadata flush is triggered after changin status of each
single sector is cache line.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
After second dirty write to cache line which was already dirty, metadata flush
was not triggered. In case of dirty shutdown, this led to data corruption.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
