When IO queues are used for parallelized management operations,
e.g. changing cleaning policy, a deadlock may occur due to global
metadata lock interfering with taking request from IO queue,
as they might be run on the same thread. As a workaround using
a management queue specifically for such operations eliminates
this problem.
Signed-off-by: Rafal Stefanowski <rafal.stefanowski@huawei.com>
Eliminate need to resolve cache based on the queue. This allows to share
the queue between cache instances. The queue still holds pointer to
a cache that owns the queue, but no management or io path relies on the
queue -> cache mapping.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
Management path does not benefit much from mpools, as number of requests
allocated is very small. It's less restrictive (mngt_queue does not have
single-CPU affinity) thus avoiding mpool usage in management path allows
to introduce additional restrictions on mpool, leading to I/O performance
improvement.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
In situation when all the shards finish their work before parallelize
loop does it's final loop condition check, which involves access to
parallelize object, it's possible that parallelize object will be
deinitialized before this final access.
Increasing refcount by 1 before running parallelize and decreasing it
only after the loop is finished addresses this problem.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
In some scenarios running the exact number of shards, regardless of
number of available queues is crucial for correctness of operation.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
Otherwise, it may increase the number of hits, while the overall performance
has not been improved. This way, the hit rate is more correlated with
the performance changes.
Signed-off-by: Michael Lyulko <michael.lyulko@huawei.com>
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
The completion function should be the same either when it is called from
the queue context or from currnet context
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
Commit db6b009ef introduced changes in managing the master request life cycle,
but apparently not all paths have been updated. This change removes a redundant
ocf_req_get() before sending the requets into a queue
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
When flushing a request, the number of cache reads is unknown until all cache
lines are locked and the IOs are actually submitted.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@huawei.com>
Now the request can be pushed to a high priority queue (instead of ocf_queue_push_req_front)
and to a low priority queue (instead of ocf_queue_push_req_back).
Both functions were merged into one function (ocf_queue_push_req) and instead of the
allow_sync parameter there is now a flags parameter that can be an OR combination of
OCF_QUEUE_ALLOW_SYNC and OCF_QUEUE_PRIO_HIGH
Signed-off-by: Ian Levine <ian.levine@huawei.com>
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
This functionality is used by cleaning policies via cmpl_queue
to reschedule the completion, so that we avoid unlocking mutex in
the cleaner completion from interrupt context of IO completion.
This reverts commit 1e5eda68a7.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
The flush_data is used by ocf_cleaner_do_flush_data_async(), which means
that callers of ocf_cleaner_fire() are now expected to guarantee that
entries are returned by getter in a sorted order. Currently the only case
when ocf_cleaner_fire() is called directly is for request cleaning, and
the request map is sorted by definition.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
Cache mngt lock cannot be unlocked from io completion context (which is
potentially atomic context) as it may involve sleeping operations.
Modify cleaner utility to support rescheduling to queue context before
calling the completion. Update cleaning policies to use that option.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
there is an issue when someone call to parallelize/pipeline
with some struct that is aligned (say to 64B)
but these APIs add their own data, right before
the user's private data.
so, the user's data is no longer aligned
which might cause segfault in some cases.
Signed-off-by: Amir Haroush <amir.haroush@huawei.com>
Signed-off-by: Shai Fultheim <shai.fultheim@huawei.com>
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Remove one callback indirection level. I/O never changes it's direction
so there is no point in storing both read and write callbacks for each
request.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Flush I/O should be forwarded to core and cache device. In case of core
this is simple - just mirror the I/O from the top volume. Since
cache data is owned by OCF it makes sense to send a simple flush I/O
with 0 address and size.
Current implementation attempts to use cache data I/O interface
(ocf_submit_cache_reqs function) instead of submitting empty flush to
the underlying cache device. This function is designed to read/write
from mapped cachelines while there is no traversation/mapping
performed on flush I/O.
If request map allocation succeeds, this results in sending I/O to
addres 0 with size and flags inherited from the top adapter I/O.
This doesn't make any sense, and can even result in invalid I/O if the
size is greater than cache device size.
Even worse, if flush request map allocation fails (which happens
always in case of large flush requests) then the erroneous call to
ocf_submit_cache_reqs results in NULL pointer dereference.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Right now alock assumes that number of locks taken will equal number of
core lines. This is not the case in pio, where only parts of metadata
are under locks. If pio request overlaps locked and not-locked metadata
section it will have different core lines number and awaited locks
number. To remedy this discrepancy additional method which gets count of
locks that will be taken/waited on is added to alock API.
Signed-off-by: Jan Musial <jan.musial@intel.com>
Introduce utility that allows to parallelize management operation across
all available io queues.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
