I send the kthread worker API improvements separately as discussed in v6, see https://lkml.kernel.org/g/20160511105224.GE2749@xxxxxxxxxxxxxxx I will send the conversion of the particular kthreads once the API changes are in some maintainers three (-mm?) and visible in linux-next. If nobody suggests some other approach. Also I plan to continue with conversion of more kthreads. Just to remember. The intention of this patchset is to make it easier to manipulate and maintain kthreads. Especially, I want to replace all the custom main cycles with a generic one. Also I want to make the kthreads sleep in a consistent state in a common place when there is no work. Changes against v9: + Reverted change of the INIT() macro names. + Removed the controversial kthread_drain_worker(). Flush is enough for the kthread worker API users. + Used lockdep_assert() in queuing_blocked() instead of a comment. Needed to pass worker as the parameter. + Small corrections in few comments and commit messages as suggested. + Added taken Acks. Changes against v8: + Fixed names of DEFINE() and INIT() macros. Please, find more comments in the 2nd patch. Changes against v7: + Fix up all names of functions and macros to be prefixed by kthread_/KTHREAD_; This is done also for existing functions and macros, see the first two patches Changes against v6: + no changes. Changes against v5: + removed spin_trylock() from delayed_kthread_work_timer_fn(); instead temporary released worked->lock() when calling del_timer_sync(); made sure that any queueing was blocked by work->canceling in the mealtime + used 0th byte for KTW_FREEZABLE to reduce confusion + fixed warnings in comments reported by make htmldocs + sigh, there was no easy way to create an empty va_list that would work on all architectures; decided to make @namefmt generic in create_kthread_worker_on_cpu() + converted khungtaskd a better way; it was inspired by the recent changes that appeared in 4.6-rc1 Changes against v4: + added worker->delayed_work_list; it simplified the check for pending work; we do not longer need the new timer_active() function; also we do not need the link work->timer. On the other hand we need to distinguish between the normal and the delayed work by a boolean parameter passed to the common functions, e.g. __cancel_kthread_work_sync() + replaced most try_lock repeat cycles with a WARN_ON(); the API does not allow to use the work with more workers; so such a situation would be a bug; it removed the complex try_lock_kthread_work() function that supported more modes; + renamed kthread_work_pending() to queuing_blocked(); added this function later when really needed + renamed try_to_cancel_kthread_work() to __cancel_kthread_work(); in fact, this a common implementation for the async cancel() function + removed a dull check for invalid cpu number in create_kthread_worker_on_cpu(); removed some other unnecessary code structures as suggested by Tejun + consistently used bool return value in all new __cancel functions + fixed ordering of cpu and flags parameters in create_kthread_worker_on_cpu() vs. create_kthread_worker() + used memset in the init_kthread_worker() + updated many comments as suggested by Tejun and as required the above changes + removed obsolete patch adding timer_active() + removed obsolete patch for using try_lock in flush_kthread_worker() + double checked all existing users of kthread worker API that they reinitialized the work when the worker was started and would not print false warnings; all looked fine + added taken acks for the Intel Powerclamp conversion Changes against v3: + allow to free struct kthread_work from its callback; do not touch the struct from the worker post-mortem; as a side effect, the structure must be reinitialized when the worker gets restarted; updated khugepaged, and kmemleak accordingly + call del_timer_sync() with worker->lock; instead, detect canceling in the timer callback and give up an attempt to get the lock there; do busy loop with spin_is_locked() to reduce cache bouncing + renamed ipmi+func() -> ipmi_kthread_worker_func() as suggested by Corey + added some collected Reviewed-by Changes against v2: + used worker->lock to synchronize the operations with the work instead of the PENDING bit as suggested by Tejun Heo; it simplified the implementation in several ways + added timer_active(); used it together with del_timer_sync() to cancel the work a less tricky way + removed the controversial conversion of the RCU kthreads + added several other examples: hung_task, kmemleak, ipmi, IB/fmr_pool, memstick/r592, intel_powerclamp + the helper fixes for the ring buffer benchmark has been improved as suggested by Steven; they already are in the Linus tree now + fixed a possible race between the check for existing khugepaged worker and queuing the work Changes against v1: + remove wrappers to manipulate the scheduling policy and priority + remove questionable wakeup_and_destroy_kthread_worker() variant + do not check for chained work when draining the queue + allocate struct kthread worker in create_kthread_work() and use more simple checks for running worker + add support for delayed kthread works and use them instead of waiting inside the works + rework the "unrelated" fixes for the ring buffer benchmark as discussed in the 1st RFC; also sent separately + convert also the consumer in the ring buffer benchmark I have tested this patch set against the stable Linus tree for 4.8-rc1. Comments against v9 can be found at https://lkml.kernel.org/g/1466075851-24013-1-git-send-email-pmladek@xxxxxxxx Petr Mladek (11): kthread: Rename probe_kthread_data() to kthread_probe_data() kthread: Kthread worker API cleanup kthread/smpboot: Do not park in kthread_create_on_cpu() kthread: Allow to call __kthread_create_on_node() with va_list args kthread: Add kthread_create_worker*() kthread: Add kthread_destroy_worker() kthread: Detect when a kthread work is used by more workers kthread: Initial support for delayed kthread work kthread: Allow to cancel kthread work kthread: Allow to modify delayed kthread work kthread: Better support freezable kthread workers Documentation/RCU/lockdep-splat.txt | 2 +- arch/x86/kvm/i8254.c | 14 +- crypto/crypto_engine.c | 16 +- drivers/block/loop.c | 8 +- drivers/infiniband/sw/rdmavt/cq.c | 10 +- drivers/md/dm-rq.c | 6 +- drivers/md/dm.c | 4 +- drivers/media/pci/ivtv/ivtv-driver.c | 6 +- drivers/media/pci/ivtv/ivtv-irq.c | 2 +- drivers/net/ethernet/microchip/encx24j600.c | 10 +- drivers/spi/spi.c | 18 +- drivers/tty/serial/sc16is7xx.c | 22 +- include/linux/kthread.h | 77 +++- kernel/kthread.c | 577 ++++++++++++++++++++++++---- kernel/smpboot.c | 5 + kernel/workqueue.c | 2 +- sound/soc/intel/baytrail/sst-baytrail-ipc.c | 2 +- sound/soc/intel/common/sst-ipc.c | 6 +- sound/soc/intel/haswell/sst-haswell-ipc.c | 2 +- sound/soc/intel/skylake/skl-sst-ipc.c | 2 +- 20 files changed, 645 insertions(+), 146 deletions(-) -- 1.8.5.6 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
