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Message-Id: <1470754545-17632-1-git-send-email-pmladek@suse.com>
Date: Tue, 9 Aug 2016 16:55:34 +0200
From: Petr Mladek <pmladek@...e.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>, Tejun Heo <tj@...nel.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>
Cc: Steven Rostedt <rostedt@...dmis.org>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Josh Triplett <josh@...htriplett.org>,
Thomas Gleixner <tglx@...utronix.de>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Jiri Kosina <jkosina@...e.cz>, Borislav Petkov <bp@...e.de>,
Michal Hocko <mhocko@...e.cz>, linux-mm@...ck.org,
Vlastimil Babka <vbabka@...e.cz>, linux-api@...r.kernel.org,
linux-kernel@...r.kernel.org, Petr Mladek <pmladek@...e.com>
Subject: [PATCH v10 00/11] kthread: Kthread worker API improvements
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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