Boqun pointed out that workqueues aren't handling BH work items on offlined
CPUs. Unlike tasklet which transfers out the pending tasks from
CPUHP_SOFTIRQ_DEAD, BH workqueue would just leave them pending which is
problematic. Note that this behavior is specific to BH workqueues as the
non-BH per-CPU workers just become unbound when the CPU goes offline.
This patch fixes the issue by draining the pending BH work items from an
offlined CPU from CPUHP_SOFTIRQ_DEAD. Because work items carry more context,
it's not as easy to transfer the pending work items from one pool to
another. Instead, run BH work items which execute the offlined pools on an
online CPU.
Note that this assumes that no further BH work items will be queued on the
offlined CPUs. This assumption is shared with tasklet and should be fine for
conversions. However, this issue also exists for per-CPU workqueues which
will just keep executing work items queued after CPU offline on unbound
workers and workqueue should reject per-CPU and BH work items queued on
offline CPUs. This will be addressed separately later.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Link: http://lkml.kernel.org/r/Zdvw0HdSXcU3JZ4g@boqun-archlinux
To streamline the transition from tasklets to worqueues, a new helper
function, from_work(), is introduced. This helper, inspired by existing
from_() patterns, utilizes container_of() and eliminates the redundancy
of declaring variable types, leading to more concise and readable code.
The modified code snippet demonstrates the enhanced clarity achieved
with from_wq():
void callback(struct work_struct *w)
{
- struct some_data_structure *local = container_of(w,
struct some_data_structure,
work);
+ struct some_data_structure *local = from_work(local, w, work);
This change aims to facilitate a smoother transition and uphold code
quality standards.
Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git disable_work-v3
Signed-off-by: Allen Pais <allen.lkml@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
When CONFIG_WQ_CPU_INTENSIVE_REPORT is set, the kernel will report
the work functions which violate the intensive_threshold_us repeatedly.
And now, only when the violate times exceed 4 and is a power of 2,
the kernel warning could be triggered.
However, sometimes, even if a long work execution time occurs only once,
it may cause other work to be delayed for a long time. This may also
cause some problems sometimes.
In order to freely control the threshold of warninging, a boot argument
is added so that the user can control the warning threshold to be printed.
At the same time, keep the exponential backoff to prevent reporting too much.
By default, the warning threshold is 4.
tj: Updated kernel-parameters.txt description.
Signed-off-by: Xuewen Yan <xuewen.yan@unisoc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
- set_work_data() takes a separate @flags argument but just ORs it to @data.
This is more confusing than helpful. Just take @data.
- Use the name @flags consistently and add the parameter to
set_work_pool_and_{keep|clear}_pending(). This will be used by the planned
disable/enable support.
No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
clear_work_data() is only used in one place and immediately followed by
smp_mb(), making it equivalent to set_work_pool_and_clear_pending() w/
WORK_OFFQ_POOL_NONE for @pool_id. Drop it. No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The planned disable/enable support will need the same logic. Let's factor it
out. No functional changes.
v2: Update function comment to include @irq_flags.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The bits of work->data are used for a few different purposes. How the bits
are used is determined by enum work_bits. The planned disable/enable support
will add another use, so let's clean it up a bit in preparation.
- Let WORK_STRUCT_*_BIT's values be determined by enum definition order.
- Deliminate different bit sections the same way using SHIFT and BITS
values.
- Rename __WORK_OFFQ_CANCELING to WORK_OFFQ_CANCELING_BIT for consistency.
- Introduce WORK_STRUCT_PWQ_SHIFT and replace WORK_STRUCT_FLAG_MASK and
WORK_STRUCT_WQ_DATA_MASK with WQ_STRUCT_PWQ_MASK for clarity.
- Improve documentation.
No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The cancel path used bool @is_dwork to distinguish canceling a regular work
and a delayed one. The planned disable/enable support will need passing
around another flag in the code path. As passing them around with bools will
be confusing, let's introduce named flags to pass around in the cancel path.
WORK_CANCEL_DELAYED replaces @is_dwork. No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Using the generic term `flags` for irq flags is conventional but can be
confusing as there's quite a bit of code dealing with work flags which
involves some subtleties. Let's use a more explicit name `irq_flags` for
local irq flags. No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
They are currently a bit disorganized with flush and cancel functions mixed.
Reoranize them so that flush functions come first, cancel next and
cancel_sync last. This way, we won't have to add prototypes for internal
functions for the planned disable/enable support.
This is pure code reorganization. No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
__cancel_work_timer() is used to implement cancel_work_sync() and
cancel_delayed_work_sync(), similarly to how __cancel_work() is used to
implement cancel_work() and cancel_delayed_work(). ie. The _timer part of
the name is a complete misnomer. The difference from __cancel_work() is the
fact that it syncs against work item execution not whether it handles timers
or not.
Let's rename it to less confusing __cancel_work_sync(). No functional
change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The different flavors of RCU read critical sections have been unified. Let's
update the locking assertion macros accordingly to avoid requiring
unnecessary explicit rcu_read_[un]lock() calls.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reorder some global declarations and adjust comments and whitespaces for
clarity and consistency. No functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
The device-mapper has a flag to mark targets as singleton, which is a
required flag for immutable targets. Without this flag, multiple
dm-verity targets can be added to a mapped device, which has no
practical use cases and will let dm_table_get_immutable_target return
NULL. This patch adds the missing flag, restricting only one
dm-verity target per mapped device.
Signed-off-by: Fan Wu <wufan@linux.microsoft.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Since dm-crypt queues writes to a different kernel thread (workqueue),
the bios will dispatch from tasks with different io_context->ioprio
settings and blkcg than the submitting task, thus giving incorrect
ioprio to the io scheduler.
Get the original IO priority setting via struct dm_crypt_io::base_bio
and set this priority in the bio for write.
Link: https://lore.kernel.org/dm-devel/alpine.LRH.2.11.1612141049250.13402@mail.ewheeler.net
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
After obtaining the data, verification or error correction process may
trigger a new IO that loses the priority of the original IO, that is,
the verification of the higher priority IO may be blocked by the lower
priority IO.
Make the IO used for verification and error correction follow the
priority of the original IO.
Co-developed-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Some IO will dispatch from kworker with different io_context settings
than the submitting task, we may need to specify a priority to avoid
losing priority.
Add dm_bufio_read_with_ioprio() and dm_bufio_prefetch_with_ioprio()
for use by bufio users to pass an ioprio other than IOPRIO_DEFAULT.
Co-developed-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
[snitzer: introduced _with_ioprio() wrappers to reduce churn]
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Some IO will dispatch from kworker with different io_context settings
than the submitting task, we may need to specify a priority to avoid
losing priority.
Add IO priority parameter to dm_io() and update all callers.
Co-developed-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Yibin Ding <yibin.ding@unisoc.com>
Signed-off-by: Hongyu Jin <hongyu.jin@unisoc.com>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
The task status has been set to TASK_RUNNING in schedule().
No need to set again here.
Signed-off-by: Lizhe <sensor1010@163.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
"struct bvec_iter" is defined with the __packed attribute, so it is
aligned on a single byte. On X86 (and on other architectures that support
unaligned addresses in hardware), "struct bvec_iter" is accessed using the
8-byte and 4-byte memory instructions, however these instructions are less
efficient if they operate on unaligned addresses.
(on RISC machines that don't have unaligned access in hardware, GCC
generates byte-by-byte accesses that are very inefficient - see [1])
This commit reorders the entries in "struct dm_verity_io" and "struct
convert_context", so that "struct bvec_iter" is aligned on 8 bytes.
[1] https://lore.kernel.org/all/ZcLuWUNRZadJr0tQ@fedora/T/
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
If a userspace process reads (with O_DIRECT) multiple blocks into the same
buffer, dm-crypt reports an authentication error [1]. The error is
reported in a log and it may cause RAID leg being kicked out of the
array.
This commit fixes dm-crypt, so that if integrity verification fails, the
data is read again into a kernel buffer (where userspace can't modify it)
and the integrity tag is rechecked. If the recheck succeeds, the content
of the kernel buffer is copied into the user buffer; if the recheck fails,
an integrity error is reported.
[1] https://people.redhat.com/~mpatocka/testcases/blk-auth-modify/read2.c
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
It was said that authenticated encryption could produce invalid tag when
the data that is being encrypted is modified [1]. So, fix this problem by
copying the data into the clone bio first and then encrypt them inside the
clone bio.
This may reduce performance, but it is needed to prevent the user from
corrupting the device by writing data with O_DIRECT and modifying them at
the same time.
[1] https://lore.kernel.org/all/20240207004723.GA35324@sol.localdomain/T/
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
If a userspace process reads (with O_DIRECT) multiple blocks into the same
buffer, dm-verity reports an error [1].
This commit fixes dm-verity, so that if hash verification fails, the data
is read again into a kernel buffer (where userspace can't modify it) and
the hash is rechecked. If the recheck succeeds, the content of the kernel
buffer is copied into the user buffer; if the recheck fails, an error is
reported.
[1] https://people.redhat.com/~mpatocka/testcases/blk-auth-modify/read2.c
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
If a userspace process reads (with O_DIRECT) multiple blocks into the same
buffer, dm-integrity reports an error [1]. The error is reported in a log
and it may cause RAID leg being kicked out of the array.
This commit fixes dm-integrity, so that if integrity verification fails,
the data is read again into a kernel buffer (where userspace can't modify
it) and the integrity tag is rechecked. If the recheck succeeds, the
content of the kernel buffer is copied into the user buffer; if the
recheck fails, an integrity error is reported.
[1] https://people.redhat.com/~mpatocka/testcases/blk-auth-modify/read2.c
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2f34d7337d ("workqueue: Fix queue_work_on() with BH workqueues") added
irq_work usage to workqueue; however, it turns out irq_work is actually
optional and the change breaks build on configuration which doesn't have
CONFIG_IRQ_WORK enabled.
Fix build by making workqueue use irq_work only when CONFIG_SMP and enabling
CONFIG_IRQ_WORK when CONFIG_SMP is set. It's reasonable to argue that it may
be better to just always enable it. However, this still saves a small bit of
memory for tiny UP configs and also the least amount of change, so, for now,
let's keep it conditional.
Verified to do the right thing for x86_64 allnoconfig and defconfig, and
aarch64 allnoconfig, allnoconfig + prink disable (SMP but nothing selects
IRQ_WORK) and a modified aarch64 Kconfig where !SMP and nothing selects
IRQ_WORK.
v2: `depends on SMP` leads to Kconfig warnings when CONFIG_IRQ_WORK is
selected by something else when !CONFIG_SMP. Use `def_bool y if SMP`
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Fixes: 2f34d7337d ("workqueue: Fix queue_work_on() with BH workqueues")
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
When queue_work_on() is used to queue a BH work item on a remote CPU, the
work item is queued on that CPU but kick_pool() raises softirq on the local
CPU. This leads to stalls as the work item won't be executed until something
else on the remote CPU schedules a BH work item or tasklet locally.
Fix it by bouncing raising softirq to the target CPU using per-cpu irq_work.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4cb1ef6460 ("workqueue: Implement BH workqueues to eventually replace tasklets")
Async can schedule a number of interdependent work items. However, since
5797b1c189 ("workqueue: Implement system-wide nr_active enforcement for
unbound workqueues"), unbound workqueues have separate min_active which sets
the number of interdependent work items that can be handled. This default
value is 8 which isn't sufficient for async and can lead to stalls during
resume from suspend in some cases.
Let's use a dedicated unbound workqueue with raised min_active.
Link: http://lkml.kernel.org/r/708a65cc-79ec-44a6-8454-a93d0f3114c3@samsung.com
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Since 5797b1c189 ("workqueue: Implement system-wide nr_active enforcement
for unbound workqueues"), unbound workqueues have separate min_active which
sets the number of interdependent work items that can be handled. This value
is currently initialized to WQ_DFL_MIN_ACTIVE which is 8. This isn't high
enough for some users, let's add an interface to adjust the setting.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fix the kernel-doc comment of the unplug_oldest_pwq() function to enable
proper processing and formatting of the embedded ASCII diagram.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Commit 85f0ab43f9 ("kernel/workqueue: Bind rescuer to unbound
cpumask for WQ_UNBOUND") modified init_rescuer() to bind rescuer of
an unbound workqueue to the cpumask in wq->unbound_attrs. However
unbound_attrs->cpumask's of all workqueues are initialized to
cpu_possible_mask and will only be changed if it has the WQ_SYSFS flag
to expose a cpumask sysfs file to be written by users. So this patch
doesn't achieve what it is intended to do.
If an unbound workqueue is created after wq_unbound_cpumask is modified
and there is no more unbound cpumask update after that, the unbound
rescuer will be bound to all CPUs unless the workqueue is created
with the WQ_SYSFS flag and a user explicitly modified its cpumask
sysfs file. Fix this problem by binding directly to wq_unbound_cpumask
in init_rescuer().
Fixes: 85f0ab43f9 ("kernel/workqueue: Bind rescuer to unbound cpumask for WQ_UNBOUND")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
When workqueue cpumask changes are committed the associated rescuer (if
one exists) affinity is not touched and this might be a problem down the
line for isolated setups.
Make sure rescuers affinity is updated every time a workqueue cpumask
changes, so that rescuers can't break isolation.
[longman: set_cpus_allowed_ptr() will block until the designated task
is enqueued on an allowed CPU, no wake_up_process() needed. Also use
the unbound_effective_cpumask() helper as suggested by Tejun.]
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Ordered workqueues does not currently follow changes made to the
global unbound cpumask because per-pool workqueue changes may break
the ordering guarantee. IOW, a work function in an ordered workqueue
may run on an isolated CPU.
This patch enables ordered workqueues to follow changes made to the
global unbound cpumask by temporaily plug or suspend the newly allocated
pool_workqueue from executing newly queued work items until the old
pwq has been properly drained. For ordered workqueues, there should
only be one pwq that is unplugged, the rests should be plugged.
This enables ordered workqueues to follow the unbound cpumask changes
like other unbound workqueues at the expense of some delay in execution
of work functions during the transition period.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Add a new pwq into the tail of wq->pwqs so that pwq iteration will
start from the oldest pwq to the newest. This ordering will facilitate
the inclusion of ordered workqueues in a wq_unbound_cpumask update.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The for-6.8-fixes commit ae9cc8956944 ("Revert "workqueue: Override implicit
ordered attribute in workqueue_apply_unbound_cpumask()") also fixes build for
Signed-off-by: Tejun Heo <tj@kernel.org>
This reverts commit ca10d851b9.
The commit allowed workqueue_apply_unbound_cpumask() to clear __WQ_ORDERED
on now removed implicitly ordered workqueues. This was incorrect in that
system-wide config change shouldn't break ordering properties of all
workqueues. The reason why apply_workqueue_attrs() path was allowed to do so
was because it was targeting the specific workqueue - either the workqueue
had WQ_SYSFS set or the workqueue user specifically tried to change
max_active, both of which indicate that the workqueue doesn't need to be
ordered.
The implicitly ordered workqueue promotion was removed by the previous
commit 3bc1e711c2 ("workqueue: Don't implicitly make UNBOUND workqueues w/
@max_active==1 ordered"). However, it didn't update this path and broke
build. Let's revert the commit which was incorrect in the first place which
also fixes build.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 3bc1e711c2 ("workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered")
Fixes: ca10d851b9 ("workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()")
Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Tejun Heo <tj@kernel.org>
5c0338c687 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
automoatically promoted UNBOUND workqueues w/ @max_active==1 to ordered
workqueues because UNBOUND workqueues w/ @max_active==1 used to be the way
to create ordered workqueues and the new NUMA support broke it. These
problems can be subtle and the fact that they can only trigger on NUMA
machines made them even more difficult to debug.
However, overloading the UNBOUND allocation interface this way creates other
issues. It's difficult to tell whether a given workqueue actually needs to
be ordered and users that legitimately want a min concurrency level wq
unexpectedly gets an ordered one instead. With planned UNBOUND workqueue
udpates to improve execution locality and more prevalence of chiplet designs
which can benefit from such improvements, this isn't a state we wanna be in
forever.
There aren't that many UNBOUND w/ @max_active==1 users in the tree and the
preceding patches audited all and converted them to
alloc_ordered_workqueue() as appropriate. This patch removes the implicit
promotion of UNBOUND w/ @max_active==1 workqueues to ordered ones.
v2: v1 patch incorrectly dropped !list_empty(&wq->pwqs) condition in
apply_workqueue_attrs_locked() which spuriously triggers WARNING and
fails workqueue creation. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Link: https://lore.kernel.org/oe-lkp/202304251050.45a5df1f-oliver.sang@intel.com
Skip updating workqueues with __WQ_DESTROYING bit set when updating
global unbound cpumask to avoid unnecessary work and other complications.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This reverts commit d412ace111. This leads to
build failures as it depends on a driver-core commit 32f78abe59 ("driver
core: bus: constantify subsys_register() calls"). Let's drop it from wq tree
and route it through driver-core tree.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402051505.kM9Rr3CJ-lkp@intel.com/
The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws such as
the execution code accessing the tasklet item after the execution is
complete which can lead to subtle use-after-free in certain usage scenarios
and less-developed flush and cancel mechanisms.
This patch implements BH workqueues which share the same semantics and
features of regular workqueues but execute their work items in the softirq
context. As there is always only one BH execution context per CPU, none of
the concurrency management mechanisms applies and a BH workqueue can be
thought of as a convenience wrapper around softirq.
Except for the inability to sleep while executing and lack of max_active
adjustments, BH workqueues and work items should behave the same as regular
workqueues and work items.
Currently, the execution is hooked to tasklet[_hi]. However, the goal is to
convert all tasklet users over to BH workqueues. Once the conversion is
complete, tasklet can be removed and BH workqueues can directly take over
the tasklet softirqs.
system_bh[_highpri]_wq are added. As queue-wide flushing doesn't exist in
tasklet, all existing tasklet users should be able to use the system BH
workqueues without creating their own workqueues.
v3: - Add missing interrupt.h include.
v2: - Instead of using tasklets, hook directly into its softirq action
functions - tasklet[_hi]_action(). This is slightly cheaper and closer
to the eventual code structure we want to arrive at. Suggested by Lai.
- Lai also pointed out several places which need NULL worker->task
handling or can use clarification. Updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/CAHk-=wjDW53w4-YcSmgKC5RruiRLHmJ1sXeYdp_ZgVoBw=5byA@mail.gmail.com
Tested-by: Allen Pais <allen.lkml@gmail.com>
Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com>
Factor out init_cpu_worker_pool() from workqueue_init_early(). This is pure
reorganization in preparation of BH workqueue support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Allen Pais <allen.lkml@gmail.com>
These changes are in preparation of BH workqueue which will execute work
items from BH context.
- Update lock and RCU depth checks in process_one_work() so that it
remembers and checks against the starting depths and prints out the depth
changes.
- Factor out lockdep annotations in the flush paths into
touch_{wq|work}_lockdep_map(). The work->lockdep_map touching is moved
from __flush_work() to its callee - start_flush_work(). This brings it
closer to the wq counterpart and will allow testing the associated wq's
flags which will be needed to support BH workqueues. This is not expected
to cause any functional changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Allen Pais <allen.lkml@gmail.com>
Now that the driver core can properly handle constant struct bus_type,
move the wq_subsys variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Suggested-and-reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ricardo B. Marliere <ricardo@marliere.net>
Signed-off-by: Tejun Heo <tj@kernel.org>
dd6c3c5441 ("workqueue: Move pwq_dec_nr_in_flight() to the end of work
item handling") relocated pwq_dec_nr_in_flight() after
set_work_pool_and_keep_pending(). However, the latter destroys information
contained in work->data that's needed by pwq_dec_nr_in_flight() including
the flush color. With flush color destroyed, flush_workqueue() can stall
easily when mixed with cancel_work*() usages.
This is easily triggered by running xfstests generic/001 test on xfs:
INFO: task umount:6305 blocked for more than 122 seconds.
...
task:umount state:D stack:13008 pid:6305 tgid:6305 ppid:6301 flags:0x00004000
Call Trace:
<TASK>
__schedule+0x2f6/0xa20
schedule+0x36/0xb0
schedule_timeout+0x20b/0x280
wait_for_completion+0x8a/0x140
__flush_workqueue+0x11a/0x3b0
xfs_inodegc_flush+0x24/0xf0
xfs_unmountfs+0x14/0x180
xfs_fs_put_super+0x3d/0x90
generic_shutdown_super+0x7c/0x160
kill_block_super+0x1b/0x40
xfs_kill_sb+0x12/0x30
deactivate_locked_super+0x35/0x90
deactivate_super+0x42/0x50
cleanup_mnt+0x109/0x170
__cleanup_mnt+0x12/0x20
task_work_run+0x60/0x90
syscall_exit_to_user_mode+0x146/0x150
do_syscall_64+0x5d/0x110
entry_SYSCALL_64_after_hwframe+0x6c/0x74
Fix it by stashing work_data before calling set_work_pool_and_keep_pending()
and using the stashed value for pwq_dec_nr_in_flight().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Chandan Babu R <chandanbabu@kernel.org>
Link: http://lkml.kernel.org/r/87o7cxeehy.fsf@debian-BULLSEYE-live-builder-AMD64
Fixes: dd6c3c5441 ("workqueue: Move pwq_dec_nr_in_flight() to the end of work item handling")
