The stall warning prints 16 bits since commit 171476775d
("context_tracking: Convert state to atomic_t").
Fixes: 171476775d ("context_tracking: Convert state to atomic_t")
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
rcu_dynticks_eqs_{enter, exit}() have been replaced by their
context-tracking counterparts since commit:
171476775d ("context_tracking: Convert state to atomic_t")
Update the stray documentation references.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, drop the dyntick reference and update the name of this helper
to express that it rechecks rdp->watching_snap after an earlier
rcu_watching_snap_save().
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the snapshot helpers are now prefix by
"rcu_watching". Reflect that change into the storage variables for these
snapshots.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, the dynticks prefix can go.
While at it, this helper is only meant to be called after failing an
earlier call to rcu_watching_snap_in_eqs(), document this in the comments
and add a WARN_ON_ONCE() for good measure.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The call_rcu_tasks_rude() and rcu_barrier_tasks_rude() APIs are no longer.
This commit therefore removes them from the documentation.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, and the 'dynticks' prefix can be dropped without losing any
meaning.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
[ neeraj.upadhyay: Fix htmldocs build error reported by Stephen Rothwell ]
Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
The context_tracking.state RCU_DYNTICKS subvariable has been renamed to
RCU_WATCHING, reflect that change in the related helpers.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
When the grace period kthread checks the extended quiescent state
counter of a CPU, full ordering is necessary to ensure that either:
* If the GP kthread observes the remote target in an extended quiescent
state, then that target must observe all accesses prior to the current
grace period, including the current grace period sequence number, once
it exits that extended quiescent state.
or:
* If the GP kthread observes the remote target NOT in an extended
quiescent state, then the target further entering in an extended
quiescent state must observe all accesses prior to the current
grace period, including the current grace period sequence number, once
it enters that extended quiescent state.
This ordering is enforced through a full memory barrier placed right
before taking the first EQS snapshot. However this is superfluous
because the snapshot is taken while holding the target's rnp lock which
provides the necessary ordering through its chain of
smp_mb__after_unlock_lock().
Remove the needless explicit barrier before the snapshot and put a
comment about the implicit barrier newly relied upon here.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit expands on the ordering properties of rcu_assign_pointer()
and rcu_dereference(), outlining their constraints on CPUs and compilers.
Reported-by: Rao Shoaib <rao.shoaib@oracle.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit adds more detail to the Tasks RCU and Tasks Rude RCU
descriptions in Requirements.rst. While in the area, add Tasks Trace
RCU to the Tasks-RCU table of contents.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
arrayRCU.rst has been removed since commit ef2555cf68 ("doc: Remove
arrayRCU.rst") but is still referenced by whatisRCU.rst. Update it to
reflect the current state of the documentation.
Signed-off-by: Zenghui Yu <zenghui.yu@linux.dev>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
- Some cleanup of the main index page for easier navigation
- Rework some of the other top-level pages for better readability and, with
luck, fewer merge conflicts in the future.
- Submit-checklist improvements, hopefully the first of many.
- New Italian translations
- A fair number of kernel-doc fixes and improvements. We have also dropped
the recommendation to use an old version of Sphinx.
- A new document from Thorsten on bisection
...and lots of fixes and updates.
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Merge tag 'docs-6.9' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"A moderatly busy cycle for development this time around.
- Some cleanup of the main index page for easier navigation
- Rework some of the other top-level pages for better readability
and, with luck, fewer merge conflicts in the future.
- Submit-checklist improvements, hopefully the first of many.
- New Italian translations
- A fair number of kernel-doc fixes and improvements. We have also
dropped the recommendation to use an old version of Sphinx.
- A new document from Thorsten on bisection
... and lots of fixes and updates"
* tag 'docs-6.9' of git://git.lwn.net/linux: (54 commits)
docs: verify/bisect: fixes, finetuning, and support for Arch
docs: Makefile: Add dependency to $(YNL_INDEX) for targets other than htmldocs
docs: Move ja_JP/howto.rst to ja_JP/process/howto.rst
docs: submit-checklist: use subheadings
docs: submit-checklist: structure by category
docs: new text on bisecting which also covers bug validation
docs: drop the version constraints for sphinx and dependencies
docs: kerneldoc-preamble.sty: Remove code for Sphinx <2.4
docs: Restore "smart quotes" for quotes
docs/zh_CN: accurate translation of "function"
docs: Include simplified link titles in main index
docs: Correct formatting of title in admin-guide/index.rst
docs: kernel_feat.py: fix build error for missing files
MAINTAINERS: Set the field name for subsystem profile section
kasan: Add documentation for CONFIG_KASAN_EXTRA_INFO
Fixed case issue with 'fault-injection' in documentation
kernel-doc: handle #if in enums as well
Documentation: update mailing list addresses
doc: kerneldoc.py: fix indentation
scripts/kernel-doc: simplify signature printing
...
This commit completes the list of call_rcu*() functions that are not
guaranteed to have their callbacks executing on the same CPU. While in
the area, fix an unrelated typo.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This commit explicitly states that you should initialize any locks to
be used by readers in your SLAB_TYPESAFE_BY_RCU constructor.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
This commit adds CONFIG_RCU_STRICT_GRACE_PERIOD to the list of debugging
Kconfig options in checklist.rst.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
In kernels built with CONFIG_PREEMPT_RT=n, spinlock critical sections
are RCU readers because they disable preemption. However, they are also
RCU readers in CONFIG_PREEMPT_RT=y because in that case the locking
primitives contain rcu_read_lock() and rcu_read_unlock(). Therefore,
upgrade checklist.rst to document this non-obvious case.
While in the area, fix a typo by changing "read-side critical" to
"read-side critical section".
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
In kernels built with CONFIG_PREEMPT_RT=n, spinlock critical sections
are RCU readers because they disable preemption. However, they are also
RCU readers in CONFIG_PREEMPT_RT=y because in that case the locking
primitives contain rcu_read_lock() and rcu_read_unlock(). Therefore,
upgrade whatisRCU.rst to document this non-obvious case.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
In kernels built with CONFIG_PREEMPT_RT=n, spinlock critical sections
are RCU readers because they disable preemption. However, they are also
RCU readers in CONFIG_PREEMPT_RT=y because the -rt locking primitives
contain rcu_read_lock() and rcu_read_unlock(). Therefore, upgrade
rcu_dereference.rst to document this non-obvious case.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=whGKvjHCtJ6W4pQ0_h_k9fiFQ8V2GpM=BqYnB2X=SJ+XQ@mail.gmail.com/
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
To begin with:
- locking/index.rst
- locking/lockdep-design.rst
- locking/lockstat.rst
- locking/lockturture.rst
- locking/locktypes.rst
And RCU/torture.rst to avoid broken references.
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240106233820.30454-1-federico.vaga@vaga.pv.it
This commit adds discussion of address and data dependencies to the
beginning of rcu_dereference.rst in order to enable readers to more
easily make the connection to the Linux-kernel memory model in general
and to memory-barriers.txt in particular.
Reported-by: Jonas Oberhauser <jonas.oberhauser@huaweicloud.com>
Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Currently, the reader/updater compatibility rules for the three RCU
Tasks flavors are squished together in a single paragraph, which can
result in confusion. This commit therefore splits them out into a list,
clearly showing the distinction between these flavors.
Link: https://lore.kernel.org/all/20231002211936.5948253e@gandalf.local.home/
Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Remove the repeated word "of" in comments.
Signed-off-by: Charles Han <hanchunchao@inspur.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
rcu_report_dead() and rcutree_migrate_callbacks() have their headers in
rcupdate.h while those are pure rcutree calls, like the other CPU-hotplug
functions.
Also rcu_cpu_starting() and rcu_report_dead() have different naming
conventions while they mirror each other's effects.
Fix the headers and propose a naming that relates both functions and
aligns with the prefix of other rcutree CPU-hotplug functions.
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
This function is gone since:
53b46303da (rcu: Remove rsp parameter from rcu_boot_init_percpu_data() and friends)
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
More explicitly state what is, and what is not guaranteed to those
who iterate a list while protected by RCU.
[ paulmck: Apply Joel Fernandes feedback. ]
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
The example code snippets on rculist_nulls.rst are assuming 'obj' to
have the 'hlist_head' or 'hlist_nulls_head' field named 'obj_node', but
a sentence and some code snippets are wrongly calling
'obj->obj_node.next' as 'obj->obj_next', or 'obj->obj_node' as 'member'.
Fix it.
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The type of 'obj' in example code of rculist_nulls.rst is implicit.
Provide the specific type of it before the example code.
Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/rcu/43943609-f80c-4b6a-9844-994eef800757@paulmck-laptop/
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Lookup example code snippets in rculist_nulls.rst are using 'obj'
without assignment. Fix the code to assign it properly.
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Lookup example of non-hlist_nulls management is missing a semicolon, and
having inconsistent indentation (one line is using single space
indentation while others are using two spaces indentation). Fix the
trivial issues.
Signed-off-by: SeongJae Park <sj@kernel.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
We should exit the RCU read-side critical section before re-entering.
Signed-off-by: Alan Huang <mmpgouride@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Since there are now exactly _zero_ users of RCU_NONIDLE(), make it go
away before someone else decides to (ab)use it.
[ paulmck: Remove extraneous whitespace. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The kfree_rcu() macro is deprecated. Rename it to its new
kfree_rcu_mightsleep() name in this documentation.
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Correct spelling problems for Documentation/RCU/ as reported
by codespell.
Note: in RTFP.txt, there are other misspellings that are left as is
since they were used that way in email Subject: lines or in LWN.net
articles. [preemptable, Preemptable, synchonisation]
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: rcu@vger.kernel.org
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
"Please not that you *cannot* rely..." has a typo.
Fix it.
Acked-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Documentation/RCU/stallwarn.rst:
401: WARNING: Literal block expected; none found.
428: WARNING: Literal block expected; none found.
445: WARNING: Literal block expected; none found.
459: WARNING: Literal block expected; none found.
468: WARNING: Literal block expected; none found.
The literal block needs to be indented, so this commit adds two spaces
to each line.
In addition, ':', which is used as a boundary in the literal block, is
replaced by '|'.
Link: https://lore.kernel.org/linux-next/20221123163255.48653674@canb.auug.org.au/
Fixes: 3d2788ba4573 ("doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Tested-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Line numbers in code snippets in rcubarrier.rst have beed left adjusted
since commit 4af498306f ("doc: Convert to rcubarrier.txt to ReST").
This might have been because right adjusting them had confused Sphinx.
The rules around a literal block in reST are:
- Need a blank line above it.
- A line with the same indent level as the line above it is regarded
as the end of it.
Those line numbers can be right adjusted by keeping indents at two-
digit numbers. While at it, add some spaces between the column of line
numbers and the code area for better readability.
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit documents the additional RCU CPU stall warning output
produced by kernels built with CONFIG_RCU_CPU_STALL_CPUTIME=y or booted
with rcupdate.rcu_cpu_stall_cputime=1.
[ paulmck: Apply wordsmithing. ]
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit updates UP.rst to reflect changes over the past few years,
including the advent of userspace RCU libraries for constrained systems.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
