Messages in this thread | | | From | Petr Mladek <> | Subject | [PATCH v10 00/11] kthread: Kthread worker API improvements | Date | Tue, 9 Aug 2016 16:55:34 +0200 |
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I send the kthread worker API improvements separately as discussed in v6, see https://lkml.kernel.org/g/20160511105224.GE2749@pathway.suse.cz
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@suse.com
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
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