This is a suboptimal solution to CAS on top of MD RAID1 device. If using
only submit_bio API RAID1 would process all IOs in single thread.
Plugging bypasses this thread and processess IOs in blk_finish_plug
caller context improving performance drastically.
Testing showed no negative impact to other usecases and it's a thing
that Linux does in AIO, so it's vetted and proven to work.
Signed-off-by: Jan Musial <jan.musial@intel.com>
Some helper threads are created at the very beginning of cache start/stop
operations, but they are used only after OCF start/stop finishes, which
may take significant amount of time. Kernel by default creates threads
that wait for the first wake up in uninterruptible state, which may trigger
hung task warning if the first wake up is called more than 120 seconds
after thread creation. To mitigate this problem we create lazy thread
abstraction that waits for a wake up in interruptible state.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
OCF cannot allocate request map bigger than 4MiB (due to kmalloc
limitations), thus we need to split bigger IOs into series smaller
ones to reduce request map size.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
It's defined on every single supported kernel, so there is actually no need
for this define at all.
Signed-off-by: Robert Baldyga <robert.baldyga@intel.com>
This patch fixes adding core after core addition failure.
The queue wasn't cleaned before and following core addition cannot
re-initialize queue properly.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
In case of initial flush error stop is aborted. In case
of failure during the second flush, appropriate error
message is presetned to the user.
Signed-off-by: Adam Rutkowski <adam.j.rutkowski@intel.com>
Don't remove inactive core if it has dirt cache lines assigned unless `force`
flag is specified.
Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>
The data->size field can be initialized to a lower value than bio->bi_vcnt,
if the bio is split. The bio_for_each_segment then iterates based on the original
indexes and the mismatch eventually causes a BUG_ON.
Fixes#714
Signed-off-by: Kozlowski Mateusz <mateusz.kozlowski@intel.com>
If time is counted in jiffies, machine reboot brokes `dirty for`
statistic for caches loaded at boot. The counter overflows and
`dirty for` shows some huge values.
Cast ticks to unsigned long.
Add necessary header.
Move `env_msleep` to `TIME` subgroup of header.
Move `env_time_after` below time converting functions.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
Create module-side handling of inactive core removal.
Extract core functionality of core removal that applies to inactive core
and copy it to `cache_mngt_remove_inactive_core` function.
Return proper error if core is active.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
New error code will allow to properly handle issues caused by wrong
usage of `remove inactive core` command.
It will also allow to print meaningful error messages.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
Change extended error message for `KCAS_ERR_REMOVED_DIRTY`.
Print informative messages when `remove core` command fails.
Make separate error messages for detaching.
Update help printouts.
Update documentation comments.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
FLush only active core during core removal.
During core removal with `casadm -R` there's a flush triggered.
This flush shall be skipped for inactive cores.
Change return code when `casadm -R` is called with `force` flag.
There was no info about dirty data when core was removed without flush.
Do not destroy exported object while core is inactive.
Perform detach only on active cores.
Skip removing inactive core with command for active cores.
Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>
