Ioctl interrupt #231

mmichal10 · 2019-12-13T09:18:54Z

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modules/cas_cache/layer_cache_management.c

modules/cas_cache/service_ui_ioctl.c

modules/cas_cache/layer_cache_management.c

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

After marking thread as ready to stop, CAS was waiting this for thread to exit out of main execution loop (in _cas_io_queue_thread()). In case of management queue it lead to deadlock because both stoping queue and main execution loop was performed in the same execution context. Since freeing memory is the only operation after stopping thread, it can be moved just after the main thread loop. After this little reordering, synchronising between _cas_stop_thread() and _cas_io_queue_thread() in no longer needed, and no deadlock will occur. This change is needed to put management qeueue from completion context. Without this cachnge, there will be no possiblitiy to stop cache from completion context and to make rollback. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

Usually metadata probe is non time consuming. To avoid dealing with synchronization problems, noninterruptible wait is performed. This commit is part of patch that will handle interrupt of waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

They are usually not time comsuming operations, so risk of hung task is low. So it's easier to temporarily disable interrupts instead of properly handle async completion. This commit is part of patch that will handle interrupt of waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

This commit is part of patch that will allow to interrupt waiting for OCF operation. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

When context was allocated on the stack and waiting for completion was interrupted, completion function would attempt to save lock/unlock result in memory which might in use by other process. This would cause a system crash. To prevent such scenario, context is allocated dynamiclly and extended with reference counter. In case of interrupt, completion function doesn't have to save result in context, it can simply free it's memory. This commit is part of patch that will allow to interrupt waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

When context was allocated on the stack and waiting for completion was interrupted, completion function would attempt to save flush result in memory which might in use by other process. This would cause a system crash. To prevent such scenario, context is allocated dynamiclly and extended with reference counter. In case of interrupt, completion function doesn't have to save result in context, it can simply free it's memory. This commit is part of patch that will allow to interrupt waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

When context was allocated on the stack and waiting for completion was interrupted, completion function would attempt to save flush result in memory which might in use by other process. This would cause a system crash. To prevent such scenario, context is allocated dynamiclly and extended with reference counter. In case of interrupt, completion function doesn't have to save result in context, it can simply free it's memory. This commit also enables possibility to interrupt regular flush properly, by seding SIGING to casadm. This commit is part of patch that will allow to interrupt waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

When device used as cache had a big size, it took a lot of time to initialize. If user would interrupt waiting, asyc OCF init procedure would continue, but after finish, there was nobody to perfrom kernel part of start nor error handling. Now error handling and kernel part of start procedure are moved to completion. If user will interrupt waiting at any point, newly started cache instance will be stopped. Since cache init and load vary only with check for old metadata and initializing exported objects, they are now merged into one function. Async cache stop is part of this commit because it was needed for rollback path. Load, init and stop have common context, because in case of non interrupted attach CAS needs to wait for rollback to be completed. Common context makes passing `struct completion` easier between load, init and stop. This commit is part of patch that will allow to interrupt waiting for OCF operations. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

In current OCF cache stop implemetation no error should occur, so there is no need to handle it in adapter. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

If waiting for the operation to finish was interrupted, casadm should print informative error message. Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

Signed-off-by: Michal Mielewczyk <michal.mielewczyk@intel.com>

…policy Initialize promotion policy before cleaning policy.

micrakow added the RFC Request For Comments label Dec 18, 2019

mmichal10 force-pushed the ioclt-interrupt branch 5 times, most recently from 8dd1833 to f14d78f Compare December 19, 2019 11:24

mmichal10 changed the title ~~[RFC]Ioclt interrupt~~ ]Ioclt interrupt Dec 19, 2019

mmichal10 removed the RFC Request For Comments label Dec 19, 2019

mmichal10 changed the title ~~]Ioclt interrupt~~ Ioclt interrupt Dec 19, 2019

mmichal10 force-pushed the ioclt-interrupt branch 6 times, most recently from b5c15ce to 2156544 Compare December 20, 2019 12:08

arutk changed the title ~~Ioclt interrupt~~ Ioctl interrupt Dec 20, 2019

arutk requested changes Dec 20, 2019

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arutk reviewed Dec 20, 2019

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