12 Jun, 2020
1 commit
-
Merge some more updates from Andrew Morton:
- various hotfixes and minor things
- hch's use_mm/unuse_mm clearnups
Subsystems affected by this patch series: mm/hugetlb, scripts, kcov,
lib, nilfs, checkpatch, lib, mm/debug, ocfs2, lib, misc.* emailed patches from Andrew Morton :
kernel: set USER_DS in kthread_use_mm
kernel: better document the use_mm/unuse_mm API contract
kernel: move use_mm/unuse_mm to kthread.c
kernel: move use_mm/unuse_mm to kthread.c
stacktrace: cleanup inconsistent variable type
lib: test get_count_order/long in test_bitops.c
mm: add comments on pglist_data zones
ocfs2: fix spelling mistake and grammar
mm/debug_vm_pgtable: fix kernel crash by checking for THP support
lib: fix bitmap_parse() on 64-bit big endian archs
checkpatch: correct check for kernel parameters doc
nilfs2: fix null pointer dereference at nilfs_segctor_do_construct()
lib/lz4/lz4_decompress.c: document deliberate use of `&'
kcov: check kcov_softirq in kcov_remote_stop()
scripts/spelling: add a few more typos
khugepaged: selftests: fix timeout condition in wait_for_scan()
11 Jun, 2020
2 commits
-
Switch the function documentation to kerneldoc comments, and add
WARN_ON_ONCE asserts that the calling thread is a kernel thread and does
not have ->mm set (or has ->mm set in the case of unuse_mm).Also give the functions a kthread_ prefix to better document the use case.
[hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio]
Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de
[sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename]
Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.auSigned-off-by: Christoph Hellwig
Signed-off-by: Stephen Rothwell
Signed-off-by: Andrew Morton
Tested-by: Jens Axboe
Reviewed-by: Jens Axboe
Acked-by: Felix Kuehling
Acked-by: Greg Kroah-Hartman [usb]
Acked-by: Haren Myneni
Cc: Alex Deucher
Cc: Al Viro
Cc: Felipe Balbi
Cc: Jason Wang
Cc: "Michael S. Tsirkin"
Cc: Zhenyu Wang
Cc: Zhi Wang
Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de
Signed-off-by: Linus Torvalds -
Patch series "improve use_mm / unuse_mm", v2.
This series improves the use_mm / unuse_mm interface by better documenting
the assumptions, and my taking the set_fs manipulations spread over the
callers into the core API.This patch (of 3):
Use the proper API instead.
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
These helpers are only for use with kernel threads, and I will tie them
more into the kthread infrastructure going forward. Also move the
prototypes to kthread.h - mmu_context.h was a little weird to start with
as it otherwise contains very low-level MM bits.Signed-off-by: Christoph Hellwig
Signed-off-by: Andrew Morton
Tested-by: Jens Axboe
Reviewed-by: Jens Axboe
Acked-by: Felix Kuehling
Cc: Alex Deucher
Cc: Al Viro
Cc: Felipe Balbi
Cc: Jason Wang
Cc: "Michael S. Tsirkin"
Cc: Zhenyu Wang
Cc: Zhi Wang
Cc: Greg Kroah-Hartman
Link: http://lkml.kernel.org/r/20200404094101.672954-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200416053158.586887-1-hch@lst.de
Link: http://lkml.kernel.org/r/20200404094101.672954-5-hch@lst.de
Signed-off-by: Linus Torvalds
09 May, 2020
1 commit
-
It's handy to keep the kthread_fn just as a unique cookie to identify
classes of kthreads. E.g. if you can verify that a given task is
running your thread_fn, then you may know what sort of type kthread_data
points to.We'll use this in nfsd to pass some information into the vfs. Note it
will need kthread_data() exported too.Original-patch-by: Tejun Heo
Signed-off-by: J. Bruce Fields
03 Apr, 2020
1 commit
-
The timer used by delayed kthread works are IRQ safe because the used
kthread_delayed_work_timer_fn() is IRQ safe.It is properly marked when initialized by KTHREAD_DELAYED_WORK_INIT().
But TIMER_IRQSAFE flag is missing when initialized by
kthread_init_delayed_work().The missing flag might trigger invalid warning from del_timer_sync() when
kthread_mod_delayed_work() is called with interrupts disabled.This patch is result of a discussion about using the API, see
https://lkml.kernel.org/r/cfa886ad-e3b7-c0d2-3ff8-58d94170eab5@ti.comReported-by: Grygorii Strashko
Signed-off-by: Petr Mladek
Signed-off-by: Andrew Morton
Tested-by: Grygorii Strashko
Acked-by: Tejun Heo
Cc: Thomas Gleixner
Link: http://lkml.kernel.org/r/20200217120709.1974-1-pmladek@suse.com
Signed-off-by: Linus Torvalds
15 May, 2019
1 commit
-
kthread.h can't be included in psi_types.h because it creates a circular
inclusion with kthread.h eventually including psi_types.h and
complaining on kthread structures not being defined because they are
defined further in the kthread.h. Resolve this by removing psi_types.h
inclusion from the headers included from kthread.h.Link: http://lkml.kernel.org/r/20190319235619.260832-7-surenb@google.com
Signed-off-by: Suren Baghdasaryan
Acked-by: Johannes Weiner
Cc: Dennis Zhou
Cc: Ingo Molnar
Cc: Jens Axboe
Cc: Li Zefan
Cc: Peter Zijlstra
Cc: Tejun Heo
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
07 Mar, 2019
1 commit
-
Pull scheduler updates from Ingo Molnar:
"The main changes in this cycle were:- refcount conversions
- Solve the rq->leaf_cfs_rq_list can of worms for real.
- improve power-aware scheduling
- add sysctl knob for Energy Aware Scheduling
- documentation updates
- misc other changes"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
kthread: Do not use TIMER_IRQSAFE
kthread: Convert worker lock to raw spinlock
sched/fair: Use non-atomic cpumask_{set,clear}_cpu()
sched/fair: Remove unused 'sd' parameter from select_idle_smt()
sched/wait: Use freezable_schedule() when possible
sched/fair: Prune, fix and simplify the nohz_balancer_kick() comment block
sched/fair: Explain LLC nohz kick condition
sched/fair: Simplify nohz_balancer_kick()
sched/topology: Fix percpu data types in struct sd_data & struct s_data
sched/fair: Simplify post_init_entity_util_avg() by calling it with a task_struct pointer argument
sched/fair: Fix O(nr_cgroups) in the load balancing path
sched/fair: Optimize update_blocked_averages()
sched/fair: Fix insertion in rq->leaf_cfs_rq_list
sched/fair: Add tmp_alone_branch assertion
sched/core: Use READ_ONCE()/WRITE_ONCE() in move_queued_task()/task_rq_lock()
sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK
sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity
sched/fair: Update scale invariance of PELT
sched/fair: Move the rq_of() helper function
sched/core: Convert task_struct.stack_refcount to refcount_t
...
28 Feb, 2019
2 commits
-
The TIMER_IRQSAFE usage was introduced in commit 22597dc3d97b1 ("kthread:
initial support for delayed kthread work") which modelled the delayed
kthread code after workqueue's code. The workqueue code requires the flag
TIMER_IRQSAFE for synchronisation purpose. This is not true for kthread's
delay timer since all operations occur under a lock.Remove TIMER_IRQSAFE from the timer initialisation and use timer_setup()
for initialisation purpose which is the official function.Signed-off-by: Sebastian Andrzej Siewior
Signed-off-by: Thomas Gleixner
Reviewed-by: Petr Mladek
Link: https://lkml.kernel.org/r/20190212162554.19779-2-bigeasy@linutronix.de -
In order to enable the queuing of kthread work items from hardirq context
even when PREEMPT_RT_FULL is enabled, convert the worker spin_lock to a
raw_spin_lock.This is only acceptable to do because the work performed under the lock is
well-bounded and minimal.Reported-by: Steffen Trumtrar
Reported-by: Tim Sander
Signed-off-by: Julia Cartwright
Signed-off-by: Sebastian Andrzej Siewior
Signed-off-by: Thomas Gleixner
Tested-by: Steffen Trumtrar
Reviewed-by: Petr Mladek
Cc: Guenter Roeck
Link: https://lkml.kernel.org/r/20190212162554.19779-1-bigeasy@linutronix.de
11 Feb, 2019
1 commit
-
kthread_should_park() is used to check if the calling kthread ('current')
should park, but there is no function to check whether an arbitrary kthread
should be parked. The latter is required to plug a CPU hotplug race vs. a
parking ksoftirqd thread.The new __kthread_should_park() receives a task_struct as parameter to
check if the corresponding kernel thread should be parked.Call __kthread_should_park() from kthread_should_park() to avoid code
duplication.Signed-off-by: Matthias Kaehlcke
Signed-off-by: Thomas Gleixner
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E . McKenney"
Cc: Sebastian Andrzej Siewior
Cc: Douglas Anderson
Cc: Stephen Boyd
Link: https://lkml.kernel.org/r/20190128234625.78241-2-mka@chromium.org
03 Jul, 2018
1 commit
-
Gaurav reports that commit:
85f1abe0019f ("kthread, sched/wait: Fix kthread_parkme() completion issue")
isn't working for him. Because of the following race:
> controller Thread CPUHP Thread
> takedown_cpu
> kthread_park
> kthread_parkme
> Set KTHREAD_SHOULD_PARK
> smpboot_thread_fn
> set Task interruptible
>
>
> wake_up_process
> if (!(p->state & state))
> goto out;
>
> Kthread_parkme
> SET TASK_PARKED
> schedule
> raw_spin_lock(&rq->lock)
> ttwu_remote
> waiting for __task_rq_lock
> context_switch
>
> finish_lock_switch
>
>
>
> Case TASK_PARKED
> kthread_park_complete
>
>
> SET RunningFurthermore, Oleg noticed that the whole scheduler TASK_PARKED
handling is buggered because the TASK_DEAD thing is done with
preemption disabled, the current code can still complete early on
preemption :/So basically revert that earlier fix and go with a variant of the
alternative mentioned in the commit. Promote TASK_PARKED to special
state to avoid the store-store issue on task->state leading to the
WARN in kthread_unpark() -> __kthread_bind().But in addition, add wait_task_inactive() to kthread_park() to ensure
the task really is PARKED when we return from kthread_park(). This
avoids the whole kthread still gets migrated nonsense -- although it
would be really good to get this done differently.Reported-by: Gaurav Kohli
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Fixes: 85f1abe0019f ("kthread, sched/wait: Fix kthread_parkme() completion issue")
Signed-off-by: Ingo Molnar
03 May, 2018
1 commit
-
Even with the wait-loop fixed, there is a further issue with
kthread_parkme(). Upon hotplug, when we do takedown_cpu(),
smpboot_park_threads() can return before all those threads are in fact
blocked, due to the placement of the complete() in __kthread_parkme().When that happens, sched_cpu_dying() -> migrate_tasks() can end up
migrating such a still runnable task onto another CPU.Normally the task will have hit schedule() and gone to sleep by the
time we do kthread_unpark(), which will then do __kthread_bind() to
re-bind the task to the correct CPU.However, when we loose the initial TASK_PARKED store to the concurrent
wakeup issue described previously, do the complete(), get migrated, it
is possible to either:- observe kthread_unpark()'s clearing of SHOULD_PARK and terminate
the park and set TASK_RUNNING, or- __kthread_bind()'s wait_task_inactive() to observe the competing
TASK_RUNNING store.Either way the WARN() in __kthread_bind() will trigger and fail to
correctly set the CPU affinity.Fix this by only issuing the complete() when the kthread has scheduled
out. This does away with all the icky 'still running' nonsense.The alternative is to promote TASK_PARKED to a special state, this
guarantees wait_task_inactive() cannot observe a 'stale' TASK_RUNNING
and we'll end up doing the right thing, but this preserves the whole
icky business of potentially migating the still runnable thing.Reported-by: Gaurav Kohli
Signed-off-by: Peter Zijlstra (Intel)
Cc: Linus Torvalds
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Signed-off-by: Ingo Molnar
22 Nov, 2017
3 commits
-
With all callbacks converted, and the timer callback prototype
switched over, the TIMER_FUNC_TYPE cast is no longer needed,
so remove it. Conversion was done with the following scripts:perl -pi -e 's|\(TIMER_FUNC_TYPE\)||g' \
$(git grep TIMER_FUNC_TYPE | cut -d: -f1 | sort -u)perl -pi -e 's|\(TIMER_DATA_TYPE\)||g' \
$(git grep TIMER_DATA_TYPE | cut -d: -f1 | sort -u)The now unused macros are also dropped from include/linux/timer.h.
Signed-off-by: Kees Cook
-
With __init_timer*() now matching __setup_timer*(), remove the redundant
internal interface, clean up the resulting definitions and add more
documentation.Cc: Thomas Gleixner
Cc: Tejun Heo
Cc: Lai Jiangshan
Cc: Shaohua Li
Cc: Jens Axboe
Cc: Andrew Morton
Signed-off-by: Kees Cook -
With the .data field removed, the ignored data arguments in timer macros
can be removed.Cc: Thomas Gleixner
Cc: Tejun Heo
Cc: Lai Jiangshan
Cc: Jens Axboe
Cc: Andrew Morton
Cc: Shaohua Li
Signed-off-by: Kees Cook
15 Nov, 2017
1 commit
-
Pull core block layer updates from Jens Axboe:
"This is the main pull request for block storage for 4.15-rc1.Nothing out of the ordinary in here, and no API changes or anything
like that. Just various new features for drivers, core changes, etc.
In particular, this pull request contains:- A patch series from Bart, closing the whole on blk/scsi-mq queue
quescing.- A series from Christoph, building towards hidden gendisks (for
multipath) and ability to move bio chains around.- NVMe
- Support for native multipath for NVMe (Christoph).
- Userspace notifications for AENs (Keith).
- Command side-effects support (Keith).
- SGL support (Chaitanya Kulkarni)
- FC fixes and improvements (James Smart)
- Lots of fixes and tweaks (Various)- bcache
- New maintainer (Michael Lyle)
- Writeback control improvements (Michael)
- Various fixes (Coly, Elena, Eric, Liang, et al)- lightnvm updates, mostly centered around the pblk interface
(Javier, Hans, and Rakesh).- Removal of unused bio/bvec kmap atomic interfaces (me, Christoph)
- Writeback series that fix the much discussed hundreds of millions
of sync-all units. This goes all the way, as discussed previously
(me).- Fix for missing wakeup on writeback timer adjustments (Yafang
Shao).- Fix laptop mode on blk-mq (me).
- {mq,name} tupple lookup for IO schedulers, allowing us to have
alias names. This means you can use 'deadline' on both !mq and on
mq (where it's called mq-deadline). (me).- blktrace race fix, oopsing on sg load (me).
- blk-mq optimizations (me).
- Obscure waitqueue race fix for kyber (Omar).
- NBD fixes (Josef).
- Disable writeback throttling by default on bfq, like we do on cfq
(Luca Miccio).- Series from Ming that enable us to treat flush requests on blk-mq
like any other request. This is a really nice cleanup.- Series from Ming that improves merging on blk-mq with schedulers,
getting us closer to flipping the switch on scsi-mq again.- BFQ updates (Paolo).
- blk-mq atomic flags memory ordering fixes (Peter Z).
- Loop cgroup support (Shaohua).
- Lots of minor fixes from lots of different folks, both for core and
driver code"* 'for-4.15/block' of git://git.kernel.dk/linux-block: (294 commits)
nvme: fix visibility of "uuid" ns attribute
blk-mq: fixup some comment typos and lengths
ide: ide-atapi: fix compile error with defining macro DEBUG
blk-mq: improve tag waiting setup for non-shared tags
brd: remove unused brd_mutex
blk-mq: only run the hardware queue if IO is pending
block: avoid null pointer dereference on null disk
fs: guard_bio_eod() needs to consider partitions
xtensa/simdisk: fix compile error
nvme: expose subsys attribute to sysfs
nvme: create 'slaves' and 'holders' entries for hidden controllers
block: create 'slaves' and 'holders' entries for hidden gendisks
nvme: also expose the namespace identification sysfs files for mpath nodes
nvme: implement multipath access to nvme subsystems
nvme: track shared namespaces
nvme: introduce a nvme_ns_ids structure
nvme: track subsystems
block, nvme: Introduce blk_mq_req_flags_t
block, scsi: Make SCSI quiesce and resume work reliably
block: Add the QUEUE_FLAG_PREEMPT_ONLY request queue flag
...
14 Nov, 2017
1 commit
-
Pull timer updates from Thomas Gleixner:
"Yet another big pile of changes:- More year 2038 work from Arnd slowly reaching the point where we
need to think about the syscalls themself.- A new timer function which allows to conditionally (re)arm a timer
only when it's either not running or the new expiry time is sooner
than the armed expiry time. This allows to use a single timer for
multiple timeout requirements w/o caring about the first expiry
time at the call site.- A new NMI safe accessor to clock real time for the printk timestamp
work. Can be used by tracing, perf as well if required.- A large number of timer setup conversions from Kees which got
collected here because either maintainers requested so or they
simply got ignored. As Kees pointed out already there are a few
trivial merge conflicts and some redundant commits which was
unavoidable due to the size of this conversion effort.- Avoid a redundant iteration in the timer wheel softirq processing.
- Provide a mechanism to treat RTC implementations depending on their
hardware properties, i.e. don't inflict the write at the 0.5
seconds boundary which originates from the PC CMOS RTC to all RTCs.
No functional change as drivers need to be updated separately.- The usual small updates to core code clocksource drivers. Nothing
really exciting"* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (111 commits)
timers: Add a function to start/reduce a timer
pstore: Use ktime_get_real_fast_ns() instead of __getnstimeofday()
timer: Prepare to change all DEFINE_TIMER() callbacks
netfilter: ipvs: Convert timers to use timer_setup()
scsi: qla2xxx: Convert timers to use timer_setup()
block/aoe: discover_timer: Convert timers to use timer_setup()
ide: Convert timers to use timer_setup()
drbd: Convert timers to use timer_setup()
mailbox: Convert timers to use timer_setup()
crypto: Convert timers to use timer_setup()
drivers/pcmcia: omap1: Fix error in automated timer conversion
ARM: footbridge: Fix typo in timer conversion
drivers/sgi-xp: Convert timers to use timer_setup()
drivers/pcmcia: Convert timers to use timer_setup()
drivers/memstick: Convert timers to use timer_setup()
drivers/macintosh: Convert timers to use timer_setup()
hwrng/xgene-rng: Convert timers to use timer_setup()
auxdisplay: Convert timers to use timer_setup()
sparc/led: Convert timers to use timer_setup()
mips: ip22/32: Convert timers to use timer_setup()
...
02 Nov, 2017
1 commit
-
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.By default all files without license information are under the default
license of the kernel, which is GPL version 2.Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if
Reviewed-by: Philippe Ombredanne
Reviewed-by: Thomas Gleixner
Signed-off-by: Greg Kroah-Hartman
05 Oct, 2017
2 commits
-
In preparation for unconditionally passing the struct timer_list pointer
to all timer callbacks, switch kthread to use from_timer() and pass the
timer pointer explicitly.Signed-off-by: Kees Cook
Signed-off-by: Thomas Gleixner
Cc: linux-mips@linux-mips.org
Cc: Len Brown
Cc: Benjamin Herrenschmidt
Cc: Lai Jiangshan
Cc: Sebastian Reichel
Cc: Kalle Valo
Cc: Paul Mackerras
Cc: Pavel Machek
Cc: linux1394-devel@lists.sourceforge.net
Cc: Chris Metcalf
Cc: linux-s390@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "James E.J. Bottomley"
Cc: Wim Van Sebroeck
Cc: Michael Ellerman
Cc: Ursula Braun
Cc: Geert Uytterhoeven
Cc: Viresh Kumar
Cc: Harish Patil
Cc: Stephen Boyd
Cc: Guenter Roeck
Cc: Manish Chopra
Cc: Petr Mladek
Cc: Arnd Bergmann
Cc: linux-pm@vger.kernel.org
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Julian Wiedmann
Cc: John Stultz
Cc: Mark Gross
Cc: linux-watchdog@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen"
Cc: Greg Kroah-Hartman
Cc: "Rafael J. Wysocki"
Cc: Oleg Nesterov
Cc: Ralf Baechle
Cc: Stefan Richter
Cc: Michael Reed
Cc: netdev@vger.kernel.org
Cc: Tejun Heo
Cc: Andrew Morton
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Sudip Mukherjee
Link: https://lkml.kernel.org/r/1507159627-127660-13-git-send-email-keescook@chromium.org -
The expires field is normally initialized during the first mod_timer()
call. It was unused by all callers, so remove it from the macro.Signed-off-by: Kees Cook
Cc: linux-mips@linux-mips.org
Cc: Petr Mladek
Cc: Benjamin Herrenschmidt
Cc: Lai Jiangshan
Cc: Sebastian Reichel
Cc: Kalle Valo
Cc: Paul Mackerras
Cc: Pavel Machek
Cc: linux1394-devel@lists.sourceforge.net
Cc: Chris Metcalf
Cc: linux-s390@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: "James E.J. Bottomley"
Cc: Wim Van Sebroeck
Cc: Michael Ellerman
Cc: Ursula Braun
Cc: Geert Uytterhoeven
Cc: Viresh Kumar
Cc: Harish Patil
Cc: Stephen Boyd
Cc: Michael Reed
Cc: Manish Chopra
Cc: Len Brown
Cc: Arnd Bergmann
Cc: linux-pm@vger.kernel.org
Cc: Heiko Carstens
Cc: Tejun Heo
Cc: Julian Wiedmann
Cc: John Stultz
Cc: Mark Gross
Cc: linux-watchdog@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Cc: "Martin K. Petersen"
Cc: Greg Kroah-Hartman
Cc: "Rafael J. Wysocki"
Cc: Oleg Nesterov
Cc: Ralf Baechle
Cc: Stefan Richter
Cc: Guenter Roeck
Cc: netdev@vger.kernel.org
Cc: Martin Schwidefsky
Cc: Andrew Morton
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Sudip Mukherjee
Link: https://lkml.kernel.org/r/1507159627-127660-12-git-send-email-keescook@chromium.org
Signed-off-by: Thomas Gleixner
27 Sep, 2017
1 commit
-
The code is only for blkcg not for all cgroups
Fixes: d4478e92d618 ("block/loop: make loop cgroup aware")
Reported-by: kbuild test robot
Signed-off-by: Shaohua Li
Signed-off-by: Jens Axboe
26 Sep, 2017
1 commit
-
kthread usually runs jobs on behalf of other threads. The jobs should be
charged to cgroup of original threads. But the jobs run in a kthread,
where we lose the cgroup context of original threads. The patch adds a
machanism to record cgroup info of original threads in kthread context.
Later we can retrieve the cgroup info and attach the cgroup info to jobs.Since this mechanism is only required by kthread, we store the cgroup
info in kthread data instead of generic task_struct.Acked-by: Tejun Heo
Signed-off-by: Shaohua Li
Signed-off-by: Jens Axboe
03 Aug, 2017
1 commit
-
The kerneldoc comment for kthread_create() had an incorrect argument
name, leading to a warning in the docs build.Correct it, and make one more small step toward a warning-free build.
Link: http://lkml.kernel.org/r/20170724135916.7f486c6f@lwn.net
Signed-off-by: Jonathan Corbet
Cc: Randy Dunlap
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Dec, 2016
1 commit
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When commit fbae2d44aa1d ("kthread: add kthread_create_worker*()")
introduced some kthread_create_...() functions which were taking
printf-like parametter, it introduced __printf attributes to some
functions (e.g. kthread_create_worker()). Nevertheless some new
functions were forgotten (they have been detected thanks to
-Wmissing-format-attribute warning flag).Add the missing __printf attributes to the newly-introduced functions in
order to detect formatting issues at build-time with -Wformat flag.Link: http://lkml.kernel.org/r/20161126193543.22672-1-nicolas.iooss_linux@m4x.org
Signed-off-by: Nicolas Iooss
Reviewed-by: Petr Mladek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
08 Dec, 2016
1 commit
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commit 23196f2e5f5d "kthread: Pin the stack via try_get_task_stack() /
put_task_stack() in to_live_kthread() function" is a workaround for the
fragile design of struct kthread being allocated on the task stack.struct kthread in its current form should be removed, but this needs
cleanups outside of kthread.c.As a first step move struct kthread away from the task stack by making it
kmalloc'ed. This allows to access kthread.exited without the magic of
trying to pin task stack and the try logic in to_live_kthread().Signed-off-by: Oleg Nesterov
Acked-by: Peter Zijlstra (Intel)
Reviewed-by: Thomas Gleixner
Cc: Chunming Zhou
Cc: Roman Pen
Cc: Petr Mladek
Cc: Andy Lutomirski
Cc: Tejun Heo
Cc: Andy Lutomirski
Cc: Alex Deucher
Cc: Andrew Morton
Link: http://lkml.kernel.org/r/20161129175057.GA5330@redhat.com
Signed-off-by: Thomas Gleixner
12 Oct, 2016
9 commits
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This macro is referenced in other kerneldoc comments, but lacks one of its
own; fix that.Link: http://lkml.kernel.org/r/20160826072313.726a3485@lwn.net
Signed-off-by: Jonathan Corbet
Reported-by: Mauro Carvalho Chehab
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
This patch allows to make kthread worker freezable via a new @flags
parameter. It will allow to avoid an init work in some kthreads.It currently does not affect the function of kthread_worker_fn()
but it might help to do some optimization or fixes eventually.I currently do not know about any other use for the @flags
parameter but I believe that we will want more flags
in the future.Finally, I hope that it will not cause confusion with @flags member
in struct kthread. Well, I guess that we will want to rework the
basic kthreads implementation once all kthreads are converted into
kthread workers or workqueues. It is possible that we will merge
the two structures.Link: http://lkml.kernel.org/r/1470754545-17632-12-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There are situations when we need to modify the delay of a delayed kthread
work. For example, when the work depends on an event and the initial delay
means a timeout. Then we want to queue the work immediately when the event
happens.This patch implements kthread_mod_delayed_work() as inspired workqueues.
It cancels the timer, removes the work from any worker list and queues it
again with the given timeout.A very special case is when the work is being canceled at the same time.
It might happen because of the regular kthread_cancel_delayed_work_sync()
or by another kthread_mod_delayed_work(). In this case, we do nothing and
let the other operation win. This should not normally happen as the caller
is supposed to synchronize these operations a reasonable way.Link: http://lkml.kernel.org/r/1470754545-17632-11-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We are going to use kthread workers more widely and sometimes we will need
to make sure that the work is neither pending nor running.This patch implements cancel_*_sync() operations as inspired by
workqueues. Well, we are synchronized against the other operations via
the worker lock, we use del_timer_sync() and a counter to count parallel
cancel operations. Therefore the implementation might be easier.First, we check if a worker is assigned. If not, the work has newer been
queued after it was initialized.Second, we take the worker lock. It must be the right one. The work must
not be assigned to another worker unless it is initialized in between.Third, we try to cancel the timer when it exists. The timer is deleted
synchronously to make sure that the timer call back is not running. We
need to temporary release the worker->lock to avoid a possible deadlock
with the callback. In the meantime, we set work->canceling counter to
avoid any queuing.Fourth, we try to remove the work from a worker list. It might be
the list of either normal or delayed works.Fifth, if the work is running, we call kthread_flush_work(). It might
take an arbitrary time. We need to release the worker-lock again. In the
meantime, we again block any queuing by the canceling counter.As already mentioned, the check for a pending kthread work is done under a
lock. In compare with workqueues, we do not need to fight for a single
PENDING bit to block other operations. Therefore we do not suffer from
the thundering storm problem and all parallel canceling jobs might use
kthread_flush_work(). Any queuing is blocked until the counter gets zero.Link: http://lkml.kernel.org/r/1470754545-17632-10-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
We are going to use kthread_worker more widely and delayed works
will be pretty useful.The implementation is inspired by workqueues. It uses a timer to queue
the work after the requested delay. If the delay is zero, the work is
queued immediately.In compare with workqueues, each work is associated with a single worker
(kthread). Therefore the implementation could be much easier. In
particular, we use the worker->lock to synchronize all the operations with
the work. We do not need any atomic operation with a flags variable.In fact, we do not need any state variable at all. Instead, we add a list
of delayed works into the worker. Then the pending work is listed either
in the list of queued or delayed works. And the existing check of pending
works is the same even for the delayed ones.A work must not be assigned to another worker unless reinitialized.
Therefore the timer handler might expect that dwork->work->worker is valid
and it could simply take the lock. We just add some sanity checks to help
with debugging a potential misuse.Link: http://lkml.kernel.org/r/1470754545-17632-9-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
The current kthread worker users call flush() and stop() explicitly.
This function does the same plus it frees the kthread_worker struct
in one call.It is supposed to be used together with kthread_create_worker*() that
allocates struct kthread_worker.Link: http://lkml.kernel.org/r/1470754545-17632-7-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Cc: Oleg Nesterov
Cc: Tejun Heo
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Kthread workers are currently created using the classic kthread API,
namely kthread_run(). kthread_worker_fn() is passed as the @threadfn
parameter.This patch defines kthread_create_worker() and
kthread_create_worker_on_cpu() functions that hide implementation details.They enforce using kthread_worker_fn() for the main thread. But I doubt
that there are any plans to create any alternative. In fact, I think that
we do not want any alternative main thread because it would be hard to
support consistency with the rest of the kthread worker API.The naming and function of kthread_create_worker() is inspired by the
workqueues API like the rest of the kthread worker API.The kthread_create_worker_on_cpu() variant is motivated by the original
kthread_create_on_cpu(). Note that we need to bind per-CPU kthread
workers already when they are created. It makes the life easier.
kthread_bind() could not be used later for an already running worker.This patch does _not_ convert existing kthread workers. The kthread
worker API need more improvements first, e.g. a function to destroy the
worker.IMPORTANT:
kthread_create_worker_on_cpu() allows to use any format of the worker
name, in compare with kthread_create_on_cpu(). The good thing is that it
is more generic. The bad thing is that most users will need to pass the
cpu number in two parameters, e.g. kthread_create_worker_on_cpu(cpu,
"helper/%d", cpu).To be honest, the main motivation was to avoid the need for an empty
va_list. The only legal way was to create a helper function that would be
called with an empty list. Other attempts caused compilation warnings or
even errors on different architectures.There were also other alternatives, for example, using #define or
splitting __kthread_create_worker(). The used solution looked like the
least ugly.Link: http://lkml.kernel.org/r/1470754545-17632-6-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
A good practice is to prefix the names of functions by the name
of the subsystem.The kthread worker API is a mix of classic kthreads and workqueues. Each
worker has a dedicated kthread. It runs a generic function that process
queued works. It is implemented as part of the kthread subsystem.This patch renames the existing kthread worker API to use
the corresponding name from the workqueues API prefixed by
kthread_:__init_kthread_worker() -> __kthread_init_worker()
init_kthread_worker() -> kthread_init_worker()
init_kthread_work() -> kthread_init_work()
insert_kthread_work() -> kthread_insert_work()
queue_kthread_work() -> kthread_queue_work()
flush_kthread_work() -> kthread_flush_work()
flush_kthread_worker() -> kthread_flush_worker()Note that the names of DEFINE_KTHREAD_WORK*() macros stay
as they are. It is common that the "DEFINE_" prefix has
precedence over the subsystem names.Note that INIT() macros and init() functions use different
naming scheme. There is no good solution. There are several
reasons for this solution:+ "init" in the function names stands for the verb "initialize"
aka "initialize worker". While "INIT" in the macro names
stands for the noun "INITIALIZER" aka "worker initializer".+ INIT() macros are used only in DEFINE() macros
+ init() functions are used close to the other kthread()
functions. It looks much better if all the functions
use the same scheme.+ There will be also kthread_destroy_worker() that will
be used close to kthread_cancel_work(). It is related
to the init() function. Again it looks better if all
functions use the same naming scheme.+ there are several precedents for such init() function
names, e.g. amd_iommu_init_device(), free_area_init_node(),
jump_label_init_type(), regmap_init_mmio_clk(),+ It is not an argument but it was inconsistent even before.
[arnd@arndb.de: fix linux-next merge conflict]
Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
Suggested-by: Andrew Morton
Signed-off-by: Petr Mladek
Cc: Oleg Nesterov
Cc: Tejun Heo
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Patch series "kthread: Kthread worker API improvements"
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.This patch (of 11):
A good practice is to prefix the names of functions by the name of the
subsystem.This patch fixes the name of probe_kthread_data(). The other wrong
functions names are part of the kthread worker API and will be fixed
separately.Link: http://lkml.kernel.org/r/1470754545-17632-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek
Suggested-by: Andrew Morton
Acked-by: Tejun Heo
Cc: Oleg Nesterov
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Steven Rostedt
Cc: "Paul E. McKenney"
Cc: Josh Triplett
Cc: Thomas Gleixner
Cc: Jiri Kosina
Cc: Borislav Petkov
Cc: Michal Hocko
Cc: Vlastimil Babka
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
05 Sep, 2015
1 commit
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- Make it clear that the `node' arg refers to memory allocations only:
kthread_create_on_node() does not pin the new thread to that node's
CPUs.- Encourage the use of NUMA_NO_NODE.
[nzimmer@sgi.com: use NUMA_NO_NODE in kthread_create() also]
Cc: Nathan Zimmer
Cc: Tejun Heo
Cc: Eric Dumazet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Aug, 2015
1 commit
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Because sched_setscheduler() checks p->flags & PF_NO_SETAFFINITY
without locks, a caller might observe an old value and race with the
set_cpus_allowed_ptr() call from __kthread_bind() and effectively undo
it:__kthread_bind()
do_set_cpus_allowed()
sched_setaffinity()
if (p->flags & PF_NO_SETAFFINITIY)
set_cpus_allowed_ptr()
p->flags |= PF_NO_SETAFFINITYFix the bug by putting everything under the regular scheduler locks.
This also closes a hole in the serialization of task_struct::{nr_,}cpus_allowed.
Signed-off-by: Peter Zijlstra (Intel)
Acked-by: Tejun Heo
Cc: Linus Torvalds
Cc: Mike Galbraith
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: dedekind1@gmail.com
Cc: juri.lelli@arm.com
Cc: mgorman@suse.de
Cc: riel@redhat.com
Cc: rostedt@goodmis.org
Link: http://lkml.kernel.org/r/20150515154833.545640346@infradead.org
Signed-off-by: Ingo Molnar
29 Jul, 2014
1 commit
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The wait_queue_head_t kthread_work->done is unused since
flush_kthread_work() has been re-implemented. Let's remove it
including the initialization code. This makes
DEFINE_KTHREAD_WORK_ONSTACK() unnecessary, removed.tj: Updated description. Removed DEFINE_KTHREAD_WORK_ONSTACK().
Signed-off-by: Lai Jiangshan
Signed-off-by: Tejun Heo
01 May, 2013
1 commit
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One of the problems that arise when converting dedicated custom threadpool
to workqueue is that the shared worker pool used by workqueue anonimizes
each worker making it more difficult to identify what the worker was doing
on which target from the output of sysrq-t or debug dump from oops, BUG()
and friends.For example, after writeback is converted to use workqueue instead of
priviate thread pool, there's no easy to tell which backing device a
writeback work item was working on at the time of task dump, which,
according to our writeback brethren, is important in tracking down issues
with a lot of mounted file systems on a lot of different devices.This patchset implements a way for a work function to mark its execution
instance so that task dump of the worker task includes information to
indicate what the work item was doing.An example WARN dump would look like the following.
WARNING: at fs/fs-writeback.c:1015 bdi_writeback_workfn+0x2b4/0x3c0()
Modules linked in:
CPU: 0 Pid: 28 Comm: kworker/u18:0 Not tainted 3.9.0-rc1-work+ #24
Hardware name: empty empty/S3992, BIOS 080011 10/26/2007
Workqueue: writeback bdi_writeback_workfn (flush-8:16)
ffffffff820a3a98 ffff88015b927cb8 ffffffff81c61855 ffff88015b927cf8
ffffffff8108f500 0000000000000000 ffff88007a171948 ffff88007a1716b0
ffff88015b49df00 ffff88015b8d3940 0000000000000000 ffff88015b927d08
Call Trace:
[] dump_stack+0x19/0x1b
[] warn_slowpath_common+0x70/0xa0
...This patch:
Implement probe_kthread_data() which returns kthread_data if accessible.
The function is equivalent to kthread_data() except that the specified
@task may not be a kthread or its vfork_done is already cleared rendering
struct kthread inaccessible. In the former case, probe_kthread_data() may
return any value. In the latter, NULL.This will be used to safely print debug information without affecting
synchronization in the normal paths. Workqueue debug info printing on
dump_stack() and friends will make use of it.Signed-off-by: Tejun Heo
Cc: Oleg Nesterov
Acked-by: Jan Kara
Cc: Dave Chinner
Cc: Ingo Molnar
Cc: Jens Axboe
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
13 Aug, 2012
1 commit
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To avoid the full teardown/setup of per cpu kthreads in the case of
cpu hot(un)plug, provide a facility which allows to put the kthread
into a park position and unpark it when the cpu comes online again.Signed-off-by: Thomas Gleixner
Reviewed-by: Namhyung Kim
Cc: Peter Zijlstra
Reviewed-by: Srivatsa S. Bhat
Cc: Rusty Russell
Reviewed-by: Paul E. McKenney
Link: http://lkml.kernel.org/r/20120716103948.236618824@linutronix.de
Signed-off-by: Thomas Gleixner
23 Jul, 2012
1 commit
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kthread_worker provides minimalistic workqueue-like interface for
users which need a dedicated worker thread (e.g. for realtime
priority). It has basic queue, flush_work, flush_worker operations
which mostly match the workqueue counterparts; however, due to the way
flush_work() is implemented, it has a noticeable difference of not
allowing work items to be freed while being executed.While the current users of kthread_worker are okay with the current
behavior, the restriction does impede some valid use cases. Also,
removing this difference isn't difficult and actually makes the code
easier to understand.This patch reimplements flush_kthread_work() such that it uses a
flush_work item instead of queue/done sequence numbers.Signed-off-by: Tejun Heo