'stop_pipeline' filed may be reused during cache lifetime (e.g. when cache is
detached and attached again - the pipeline would be freed and then
re-allocated). Calling completion after detach before freeing the pipeline may
lead to race condition.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@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>
HB lock takes inclusive metadata lock, which is taken also by metadata
flush, thus trying to call metadata flush under HB lock attempts to take
this lock recursively. In that case, if in the meantime some other thread
would try to take exclusive metadata lock, the inner inclusive lock would
block (because the lock keeps the order), with outer inclusive lock still
held, leading to a deadlock.
Signed-off-by: Robert Baldyga <robert.baldyga@huawei.com>
There are situations when we can end up in engine_pt with cache lines
locked for write. One example is engine_rd falling back to engine_pt after
failure during cache line preparation, where write lock has been already
taken. To handle this situation properly, unlock request using more general
unlock function.
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>
PyOCF needs to control random seed, to allow running tests with
pytest-xdist. Use local random object initialized with seed
from the config.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
Because context has one field which is aligned to 64B
(struct ocf_volume cache_volume) the compiler use vmovdqa (aligned)
instead of vmovdqu (unaligned) in reality the address is not 64 aligned,
it ends with 0x8, so we get this segfault.
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>
With a high dirty ratio and occupancy, OCF might unable to map cache lines
for new requests, thus pass-through the I/O to core devices. IOPS will
drop afterwards. We need to control the dirty ratio.
Existing `alru' policy gives user the chance to control the stale buffer
time, activity threshold etc. They can affect the dirty ratio of the cache
device, but in an empirical manner, more or less. Introducing
`max_dirty_ratio' can make it explicit.
At first glance, it might be better to implement a dedicated cleaner policy
directly targeting dirty ratio goal, so that the `alru' parameters remains
orthogonal. But one the other hand, we still need to flush dirty cache
lines periodically, instead of just keeping a watermark of dirty ratio.
It indicates that existing `alru' parameters are still required if we
develop a new policy, and it seems reasonable to make it a parameter.
To sum up, this patch does the following:
- added a 'max_dirty_ratio' parameter with default value 100;
- with default value 100, `alru' cleaner is identical to what is was;
- with value N less than 100, the cleaner (when waken up) will active
brought dirty ratio to N, regardless of staleness time.
Signed-off-by: David Lee <live4thee@gmail.com>
