mirror of https://github.com/torvalds/linux.git
2699 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Thomas Gleixner
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8fa7292fee |
treewide: Switch/rename to timer_delete[_sync]()
timer_delete[_sync]() replaces del_timer[_sync](). Convert the whole tree over and remove the historical wrapper inlines. Conversion was done with coccinelle plus manual fixups where necessary. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Linus Torvalds
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da0512b2a3 |
RCU fixes for v6.15:
- srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEEj5IosQTPz8XU1wRHSXnow7UH+rgFAmfs09kACgkQSXnow7UH +rg+tQf/ehvjwWwijwLfaDRuVieLUQDEiTLNAsSmDDx9p/620lAm3PtIyi4XBT4d tPH15uoqNaFF4fOwWouiIAbJTCgmzg6aOrg8U2Nc1KRGS7JdNUBMV+MxKYJncBYh NNcw97n/HGMvi2BWLFj1xdOlSEMITX5xRZArp7c/PVRCau7DDC2lj2Ht47zYPOY3 echRbQzozLiFCuHseGEiEpVfa00lq0Pg1UyWC+5cXCLVKhv6XlV1kMrsVOWMpF39 g2CXT5QCTENnPHXBj1wCTG7hZMLVjnlcCE8+tMf92lwmc1zVM5L/T3GZLFzPBb42 mJE6UhaqiLJYctplnoygWu4xhgLI4A== =MPwV -----END PGP SIGNATURE----- Merge tag 'rcu-fixes-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux Pull RCU fix from Boqun Feng: - srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT * tag 'rcu-fixes-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT |
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Paul E. McKenney
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1dc1e0b9d6 |
srcu: Make FORCE_NEED_SRCU_NMI_SAFE depend on RCU_EXPERT
The FORCE_NEED_SRCU_NMI_SAFE is useful only for those wishing to test
the SRCU code paths that accommodate architectures that do not have
NMI-safe per-CPU operations, that is, those architectures that do not
select the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option. As such, this
is a specialized Kconfig option that is not intended for casual users.
This commit therefore hides it behind the RCU_EXPERT Kconfig option.
Given that this new FORCE_NEED_SRCU_NMI_SAFE Kconfig option has no effect
unless the ARCH_HAS_NMI_SAFE_THIS_CPU_OPS Kconfig option is also selected,
it also depends on this Kconfig option.
[ paulmck: Apply Geert Uytterhoeven feedback. ]
[ boqun: Add the "Fixes" tag. ]
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Closes: https://lore.kernel.org/all/CAMuHMdX6dy9_tmpLkpcnGzxyRbe6qSWYukcPp=H1GzZdyd3qBQ@mail.gmail.com/
Fixes:
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Linus Torvalds
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3ba7dfb8da |
RCU pull request for v6.15
This pull request contains the following branches:
docs.2025.02.04a:
- Add broken-timing possibility to stallwarn.rst.
- Improve discussion of this_cpu_ptr(), add raw_cpu_ptr().
- Document self-propagating callbacks.
- Point call_srcu() to call_rcu() for detailed memory ordering.
- Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header.
- Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text.
- Remove references to old grace-period-wait primitives.
srcu.2025.02.05a:
- Introduce srcu_read_{un,}lock_fast(), which is similar to
srcu_read_{un,}lock_lite(): avoid smp_mb()s in lock and unlock at the
cost of calling synchronize_rcu() in synchronize_srcu(). Moreover, by
returning the percpu offset of the counter at srcu_read_lock_fast()
time, srcu_read_unlock_fast() can save extra pointer dereferencing,
which makes it faster than srcu_read_{un,}lock_lite().
srcu_read_{un,}lock_fast() are intended to replace
rcu_read_{un,}lock_trace() if possible.
torture.2025.02.05a:
- Add get_torture_init_jiffies() to return the start time of the test.
- Add a test_boost_holdoff module parameter to allow delaying boosting
tests when building rcutorture as built-in.
- Add grace period sequence number logging at the beginning and end of
failure/close-call results.
- Switch to hexadecimal for the expedited grace period sequence number
in the rcu_exp_grace_period trace point.
- Make cur_ops->format_gp_seqs take buffer length.
- Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool.
- Complain when invalid SRCU reader_flavor is specified.
- Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing, which forces SRCU
uses atomics even when percpu ops are NMI safe, and use the Kconfig
for SRCU lockdep testing.
misc.2025.03.04a:
- Split rcu_report_exp_cpu_mult() mask parameter and use for tracing.
- Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes().
- Fix get_state_synchronize_rcu_full() GP-start detection.
- Move RCU Tasks self-tests to core_initcall().
- Print segment lengths in show_rcu_nocb_gp_state().
- Make RCU watch ct_kernel_exit_state() warning.
- Flush console log from kernel_power_off().
- rcutorture: Allow a negative value for nfakewriters.
- rcu: Update TREE05.boot to test normal synchronize_rcu().
- rcu: Use _full() API to debug synchronize_rcu().
lazypreempt.2025.03.04a: Make RCU handle PREEMPT_LAZY better:
- Fix header guard for rcu_all_qs().
- rcu: Rename PREEMPT_AUTO to PREEMPT_LAZY.
- Update __cond_resched comment about RCU quiescent states.
- Handle unstable rdp in rcu_read_unlock_strict().
- Handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y.
- osnoise: Provide quiescent states.
- Adjust rcutorture with possible PREEMPT_RCU=n && PREEMPT_COUNT=y
combination.
- Limit PREEMPT_RCU configurations.
- Make rcutorture senario TREE07 and senario TREE10 use PREEMPT_LAZY=y.
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Merge tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux
Pull RCU updates from Boqun Feng:
"Documentation:
- Add broken-timing possibility to stallwarn.rst
- Improve discussion of this_cpu_ptr(), add raw_cpu_ptr()
- Document self-propagating callbacks
- Point call_srcu() to call_rcu() for detailed memory ordering
- Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header
- Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text
- Remove references to old grace-period-wait primitives
srcu:
- Introduce srcu_read_{un,}lock_fast(), which is similar to
srcu_read_{un,}lock_lite(): avoid smp_mb()s in lock and unlock
at the cost of calling synchronize_rcu() in synchronize_srcu()
Moreover, by returning the percpu offset of the counter at
srcu_read_lock_fast() time, srcu_read_unlock_fast() can avoid
extra pointer dereferencing, which makes it faster than
srcu_read_{un,}lock_lite()
srcu_read_{un,}lock_fast() are intended to replace
rcu_read_{un,}lock_trace() if possible
RCU torture:
- Add get_torture_init_jiffies() to return the start time of the test
- Add a test_boost_holdoff module parameter to allow delaying
boosting tests when building rcutorture as built-in
- Add grace period sequence number logging at the beginning and end
of failure/close-call results
- Switch to hexadecimal for the expedited grace period sequence
number in the rcu_exp_grace_period trace point
- Make cur_ops->format_gp_seqs take buffer length
- Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool
- Complain when invalid SRCU reader_flavor is specified
- Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing, which forces SRCU
uses atomics even when percpu ops are NMI safe, and use the Kconfig
for SRCU lockdep testing
Misc:
- Split rcu_report_exp_cpu_mult() mask parameter and use for tracing
- Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes()
- Fix get_state_synchronize_rcu_full() GP-start detection
- Move RCU Tasks self-tests to core_initcall()
- Print segment lengths in show_rcu_nocb_gp_state()
- Make RCU watch ct_kernel_exit_state() warning
- Flush console log from kernel_power_off()
- rcutorture: Allow a negative value for nfakewriters
- rcu: Update TREE05.boot to test normal synchronize_rcu()
- rcu: Use _full() API to debug synchronize_rcu()
Make RCU handle PREEMPT_LAZY better:
- Fix header guard for rcu_all_qs()
- rcu: Rename PREEMPT_AUTO to PREEMPT_LAZY
- Update __cond_resched comment about RCU quiescent states
- Handle unstable rdp in rcu_read_unlock_strict()
- Handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
- osnoise: Provide quiescent states
- Adjust rcutorture with possible PREEMPT_RCU=n && PREEMPT_COUNT=y
combination
- Limit PREEMPT_RCU configurations
- Make rcutorture senario TREE07 and senario TREE10 use
PREEMPT_LAZY=y"
* tag 'rcu-next-v6.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (59 commits)
rcutorture: Make scenario TREE07 build CONFIG_PREEMPT_LAZY=y
rcutorture: Make scenario TREE10 build CONFIG_PREEMPT_LAZY=y
rcu: limit PREEMPT_RCU configurations
rcutorture: Update ->extendables check for lazy preemption
rcutorture: Update rcutorture_one_extend_check() for lazy preemption
osnoise: provide quiescent states
rcu: Use _full() API to debug synchronize_rcu()
rcu: Update TREE05.boot to test normal synchronize_rcu()
rcutorture: Allow a negative value for nfakewriters
Flush console log from kernel_power_off()
context_tracking: Make RCU watch ct_kernel_exit_state() warning
rcu/nocb: Print segment lengths in show_rcu_nocb_gp_state()
rcu-tasks: Move RCU Tasks self-tests to core_initcall()
rcu: Fix get_state_synchronize_rcu_full() GP-start detection
torture: Make SRCU lockdep testing use srcu_read_lock_nmisafe()
srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing
rcutorture: Complain when invalid SRCU reader_flavor is specified
rcutorture: Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool
rcutorture: Make cur_ops->format_gp_seqs take buffer length
rcutorture: Add ftrace-compatible timestamp to GP# failure/close-call output
...
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Boqun Feng
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467c890f2d | Merge branches 'docs.2025.02.04a', 'lazypreempt.2025.03.04a', 'misc.2025.03.04a', 'srcu.2025.02.05a' and 'torture.2025.02.05a' | |
Ankur Arora
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8437bb84bc |
rcu: limit PREEMPT_RCU configurations
PREEMPT_LAZY can be enabled stand-alone or alongside PREEMPT_DYNAMIC which allows for dynamic switching of preemption models. The choice of PREEMPT_RCU or not, however, is fixed at compile time. Given that PREEMPT_RCU makes some trade-offs to optimize for latency as opposed to throughput, configurations with limited preemption might prefer the stronger forward-progress guarantees of PREEMPT_RCU=n. Accordingly, explicitly limit PREEMPT_RCU=y to the latency oriented preemption models: PREEMPT, PREEMPT_RT, and the runtime configurable model PREEMPT_DYNAMIC. This means the throughput oriented models, PREEMPT_NONE, PREEMPT_VOLUNTARY, and PREEMPT_LAZY will run with PREEMPT_RCU=n. Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Boqun Feng
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a56ca5619f |
rcutorture: Update ->extendables check for lazy preemption
The rcutorture_one_extend_check() function's second last check assumes that "preempt_count() & PREEMPT_MASK" is non-zero only if RCUTORTURE_RDR_PREEMPT or RCUTORTURE_RDR_SCHED bit is set. This works for preemptible RCU and for non-preemptible RCU running in a non-preemptible kernel. But it fails for non-preemptible RCU running in a preemptible kernel because then rcu_read_lock() is just preempt_disable(), which increases preempt count. This commit therefore adjusts this check to take into account the case fo non-preemptible RCU running in a preemptible kernel. Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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0be4b19edd |
rcutorture: Update rcutorture_one_extend_check() for lazy preemption
The rcutorture_one_extend_check() function's last check assumes that if cur_ops->readlock_nesting() returns greater than zero, either the RCUTORTURE_RDR_RCU_1 or the RCUTORTURE_RDR_RCU_2 bit must be set, that is, there must be at least one rcu_read_lock() in effect. This works for preemptible RCU and for non-preemptible RCU running in a non-preemptible kernel. But it fails for non-preemptible RCU running in a preemptible kernel because then RCU's cur_ops->readlock_nesting() function, which is rcu_torture_readlock_nesting(), will return the PREEMPT_MASK mask bits from preempt_count(). The result will be greater than zero if preemption is disabled, including by the RCUTORTURE_RDR_PREEMPT and RCUTORTURE_RDR_SCHED bits. This commit therefore adjusts this check to take into account the case fo non-preemptible RCU running in a preemptible kernel. [boqun: Fix the if condition and add comment] Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202502171415.8ec87c87-lkp@intel.com Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Joel Fernandes <joelagnelf@nvidia.com> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Uladzislau Rezki (Sony)
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5a562b8b3f |
rcu: Use _full() API to debug synchronize_rcu()
Switch for using of get_state_synchronize_rcu_full() and
poll_state_synchronize_rcu_full() pair to debug a normal
synchronize_rcu() call.
Just using "not" full APIs to identify if a grace period is
passed or not might lead to a false-positive kernel splat.
It can happen, because get_state_synchronize_rcu() compresses
both normal and expedited states into one single unsigned long
value, so a poll_state_synchronize_rcu() can miss GP-completion
when synchronize_rcu()/synchronize_rcu_expedited() concurrently
run.
To address this, switch to poll_state_synchronize_rcu_full() and
get_state_synchronize_rcu_full() APIs, which use separate variables
for expedited and normal states.
Reported-by: cheung wall <zzqq0103.hey@gmail.com>
Closes: https://lore.kernel.org/lkml/Z5ikQeVmVdsWQrdD@pc636/T/
Fixes:
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Uladzislau Rezki (Sony)
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8d67c1558a |
rcutorture: Allow a negative value for nfakewriters
Currently "nfakewriters" parameter can be set to any value but there is no possibility to adjust it automatically based on how many CPUs a system has where a test is run on. To address this, if the "nfakewriters" is set to negative it will be adjusted to num_online_cpus() during torture initialization. Reviewed-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Link: https://lore.kernel.org/r/20250227131613.52683-1-urezki@gmail.com Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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69381f3828 |
rcu/nocb: Print segment lengths in show_rcu_nocb_gp_state()
Analysis of an rcutorture callback-based forward-progress test failure was hampered by the lack of ->cblist segment lengths. This commit therefore adds this information, so that what would have been ".W85620.N." (there are some callbacks waiting for grace period sequence number 85620 and some number more that have not yet been assigned to a grace period) now prints as ".W2(85620).N6." (there are 2 callbacks waiting for grace period 85620 and 6 not yet assigned to a grace period). Note that "D" (done), "N" (next and not yet assigned to a grace period, and "B" (bypass, also not yet assigned to a grace period) have just the number of callbacks without the parenthesized grace-period sequence number. In contrast, "W" (waiting for the current grace period) and "R" (ready to wait for the next grace period to start) both have parenthesized grace-period sequence numbers. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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23c22d9156 |
rcu-tasks: Move RCU Tasks self-tests to core_initcall()
The timer and hrtimer softirq processing has moved to dedicated threads
for kernels built with CONFIG_IRQ_FORCED_THREADING=y. This results in
timers not expiring until later in early boot, which in turn causes the
RCU Tasks self-tests to hang in kernels built with CONFIG_PROVE_RCU=y,
which further causes the entire kernel to hang. One fix would be to
make timers work during this time, but there are no known users of RCU
Tasks grace periods during that time, so no justification for the added
complexity. Not yet, anyway.
This commit therefore moves the call to rcu_init_tasks_generic() from
kernel_init_freeable() to a core_initcall(). This works because the
timer and hrtimer kthreads are created at early_initcall() time.
Fixes:
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Paul E. McKenney
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85aad7cc41 |
rcu: Fix get_state_synchronize_rcu_full() GP-start detection
The get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full()
functions use the root rcu_node structure's ->gp_seq field to detect
the beginnings and ends of grace periods, respectively. This choice is
necessary for the poll_state_synchronize_rcu_full() function because
(give or take counter wrap), the following sequence is guaranteed not
to trigger:
get_state_synchronize_rcu_full(&rgos);
synchronize_rcu();
WARN_ON_ONCE(!poll_state_synchronize_rcu_full(&rgos));
The RCU callbacks that awaken synchronize_rcu() instances are
guaranteed not to be invoked before the root rcu_node structure's
->gp_seq field is updated to indicate the end of the grace period.
However, these callbacks might start being invoked immediately
thereafter, in particular, before rcu_state.gp_seq has been updated.
Therefore, poll_state_synchronize_rcu_full() must refer to the
root rcu_node structure's ->gp_seq field. Because this field is
updated under this structure's ->lock, any code following a call to
poll_state_synchronize_rcu_full() will be fully ordered after the
full grace-period computation, as is required by RCU's memory-ordering
semantics.
By symmetry, the get_state_synchronize_rcu_full() function should also
use this same root rcu_node structure's ->gp_seq field. But it turns out
that symmetry is profoundly (though extremely infrequently) destructive
in this case. To see this, consider the following sequence of events:
1. CPU 0 starts a new grace period, and updates rcu_state.gp_seq
accordingly.
2. As its first step of grace-period initialization, CPU 0 examines
the current CPU hotplug state and decides that it need not wait
for CPU 1, which is currently offline.
3. CPU 1 comes online, and updates its state. But this does not
affect the current grace period, but rather the one after that.
After all, CPU 1 was offline when the current grace period
started, so all pre-existing RCU readers on CPU 1 must have
completed or been preempted before it last went offline.
The current grace period therefore has nothing it needs to wait
for on CPU 1.
4. CPU 1 switches to an rcutorture kthread which is running
rcutorture's rcu_torture_reader() function, which starts a new
RCU reader.
5. CPU 2 is running rcutorture's rcu_torture_writer() function
and collects a new polled grace-period "cookie" using
get_state_synchronize_rcu_full(). Because the newly started
grace period has not completed initialization, the root rcu_node
structure's ->gp_seq field has not yet been updated to indicate
that this new grace period has already started.
This cookie is therefore set up for the end of the current grace
period (rather than the end of the following grace period).
6. CPU 0 finishes grace-period initialization.
7. If CPU 1’s rcutorture reader is preempted, it will be added to
the ->blkd_tasks list, but because CPU 1’s ->qsmask bit is not
set in CPU 1's leaf rcu_node structure, the ->gp_tasks pointer
will not be updated. Thus, this grace period will not wait on
it. Which is only fair, given that the CPU did not come online
until after the grace period officially started.
8. CPUs 0 and 2 then detect the new grace period and then report
a quiescent state to the RCU core.
9. Because CPU 1 was offline at the start of the current grace
period, CPUs 0 and 2 are the only CPUs that this grace period
needs to wait on. So the grace period ends and post-grace-period
cleanup starts. In particular, the root rcu_node structure's
->gp_seq field is updated to indicate that this grace period
has now ended.
10. CPU 2 continues running rcu_torture_writer() and sees that,
from the viewpoint of the root rcu_node structure consulted by
the poll_state_synchronize_rcu_full() function, the grace period
has ended. It therefore updates state accordingly.
11. CPU 1 is still running the same RCU reader, which notices this
update and thus complains about the too-short grace period.
The fix is for the get_state_synchronize_rcu_full() function to use
rcu_state.gp_seq instead of the root rcu_node structure's ->gp_seq field.
With this change in place, if step 5's cookie indicates that the grace
period has not yet started, then any prior code executed by CPU 2 must
have happened before CPU 1 came online. This will in turn prevent CPU
1's code in steps 3 and 11 from spanning CPU 2's grace-period wait,
thus preventing CPU 1 from being subjected to a too-short grace period.
This commit therefore makes this change. Note that there is no change to
the poll_state_synchronize_rcu_full() function, which as noted above,
must continue to use the root rcu_node structure's ->gp_seq field.
This is of course an asymmetry between these two functions, but is an
asymmetry that is absolutely required for correct operation. It is a
common human tendency to greatly value symmetry, and sometimes symmetry
is a wonderful thing. Other times, symmetry results in poor performance.
But in this case, symmetry is just plain wrong.
Nevertheless, the asymmetry does require an additional adjustment.
It is possible for get_state_synchronize_rcu_full() to see a given
grace period as having started, but for an immediately following
poll_state_synchronize_rcu_full() to see it as having not yet started.
Given the current rcu_seq_done_exact() implementation, this will
result in a false-positive indication that the grace period is done
from poll_state_synchronize_rcu_full(). This is dealt with by making
rcu_seq_done_exact() reach back three grace periods rather than just
two of them.
However, simply changing get_state_synchronize_rcu_full() function to
use rcu_state.gp_seq instead of the root rcu_node structure's ->gp_seq
field results in a theoretical bug in kernels booted with
rcutree.rcu_normal_wake_from_gp=1 due to the following sequence of
events:
o The rcu_gp_init() function invokes rcu_seq_start() to officially
start a new grace period.
o A new RCU reader begins, referencing X from some RCU-protected
list. The new grace period is not obligated to wait for this
reader.
o An updater removes X, then calls synchronize_rcu(), which queues
a wait element.
o The grace period ends, awakening the updater, which frees X
while the reader is still referencing it.
The reason that this is theoretical is that although the grace period
has officially started, none of the CPUs are officially aware of this,
and thus will have to assume that the RCU reader pre-dated the start of
the grace period. Detailed explanation can be found at [2] and [3].
Except for kernels built with CONFIG_PROVE_RCU=y, which use the polled
grace-period APIs, which can and do complain bitterly when this sequence
of events occurs. Not only that, there might be some future RCU
grace-period mechanism that pulls this sequence of events from theory
into practice. This commit therefore also pulls the call to
rcu_sr_normal_gp_init() to precede that to rcu_seq_start().
Although this fixes commit
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Paul E. McKenney
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536e8b9b80 |
srcu: Add FORCE_NEED_SRCU_NMI_SAFE Kconfig for testing
The srcu_read_lock_nmisafe() and srcu_read_unlock_nmisafe() functions map to __srcu_read_lock() and __srcu_read_unlock() on systems like x86 that have NMI-safe this_cpu_inc() operations. This makes the underlying __srcu_read_lock_nmisafe() and __srcu_read_unlock_nmisafe() functions difficult to test on (for example) x86 systems, allowing bugs to creep in. This commit therefore creates a FORCE_NEED_SRCU_NMI_SAFE Kconfig that forces those underlying functions to be used even on systems where they are not needed, thus providing better testing coverage. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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38b43eca66 |
rcutorture: Complain when invalid SRCU reader_flavor is specified
Currently, rcutorture ignores reader_flavor bits that are not in the SRCU_READ_FLAVOR_ALL bitmask, which could confuse rcutorture users into believing buggy patches had been fully tested. This commit therefore produces a splat in this case. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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5d45bdf292 |
rcutorture: Move RCU_TORTURE_TEST_{CHK_RDR_STATE,LOG_CPU} to bool
The RCU_TORTURE_TEST_CHK_RDR_STATE and RCU_TORTURE_TEST_LOG_CPU Kconfig options are pointlessly defined as tristate. This commit therefore converts them to bool. Reported-by: kernel test robot <oliver.sang@intel.com> Closes: https://lore.kernel.org/oe-lkp/202412241458.150d082b-lkp@intel.com Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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7acc2d9015 |
rcutorture: Make cur_ops->format_gp_seqs take buffer length
The Tree and Tiny implementations of rcutorture_format_gp_seqs() use hard-coded constants for the length of the buffer that they format into. This is of course an accident waiting to happen, so this commit therefore makes them take a length argument. The rcutorture calling code uses ARRAY_SIZE() to safely compute this new argument. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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65e6ff0f31 |
rcutorture: Add ftrace-compatible timestamp to GP# failure/close-call output
This commit adds an ftrace-compatible microsecond-scale timestamp to the failure/close-call output, but only in kernels built with CONFIG_RCU_TORTURE_TEST_LOG_GP=y. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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2db7ab8c10 |
rcutorture: Expand failure/close-call grace-period output
With only eight bits per grace-period sequence number, wrap can happen in 64 grace periods. This commit therefore increases this to sixteen bits for normal grace-period sequence numbers and the combined short-form polling sequence numbers, thus deferring wrap for at least 16,384 grace periods. Because expedited grace periods go faster, expand these to 24 bits, deferring wrap for at least 4,194,304 expedited grace periods. These longer wrap times makes it easier to correlate these numbers to trace-event output. Note that the low-order two bits are reserved for intra-grace-period state, hence the above wrap numbers being a factor of four smaller than you might expect. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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84ae91018a |
rcutorture: Include grace-period sequence numbers in failure/close-call
This commit includes the grace-period sequence numbers at the beginning and end of each segment in the "Failure/close-call rcutorture reader segments" list. These are in hexadecimal, and only the bottom byte. Currently, only RCU is supported, with its three sequence numbers (normal, expedited, and polled). Note that if all the grace-period sequence numbers remain the same across a given reader segment, only one copy of the number will be printed. Of course, if there is a change, both sets of values will be printed. Because the overhead of collecting this information can suppress heisenbugs, this information is collected and printed only in kernels built with CONFIG_RCU_TORTURE_TEST_LOG_GP=y. [ paulmck: Apply Nathan Chancellor feedback for IS_ENABLED(). ] [ paulmck: Apply feedback from kernel test robot. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: kernel test robot <oliver.sang@intel.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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b8726c5aa6 |
rcutorture: Add a test_boost_holdoff module parameter
This commit adds a test_boost_holdoff module parameter that tells the RCU priority-boosting tests to wait for the specified number of seconds past the start of the rcutorture test. This can be useful when rcutorture is built into the kernel (as opposed to being modprobed), especially on large systems where early start of RCU priority boosting can delay the boot sequence, which adds a full CPU's worth of load onto the system. This can in turn result in pointless stall warnings. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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4c3fca0f59 |
refscale: Add srcu_read_lock_fast() support using "srcu-fast"
This commit creates a new srcu-fast option for the refscale.scale_type module parameter that selects srcu_read_lock_fast() and srcu_read_unlock_fast(). Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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176d19eecb |
rcutorture: Add ability to test srcu_read_{,un}lock_fast()
This commit permits rcutorture to test srcu_read_{,un}lock_fast(), which
is specified by the rcutorture.reader_flavor=0x8 kernel boot parameter.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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Paul E. McKenney
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4937096b57 |
srcu: Pull integer-to-pointer conversion into __srcu_ctr_to_ptr()
This commit abstracts the srcu_read_unlock*() integer-to-pointer conversion into a new __srcu_ctr_to_ptr(). This will be used in rcutorture for testing an srcu_read_unlock_fast() that avoids array-indexing overhead by taking a pointer rather than an integer. [ paulmck: Apply kernel test robot feedback. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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f4bde41dd1 |
srcu: Pull pointer-to-integer conversion into __srcu_ptr_to_ctr()
This commit abstracts the srcu_read_lock*() pointer-to-integer conversion into a new __srcu_ptr_to_ctr(). This will be used in rcutorture for testing an srcu_read_lock_fast() that returns a pointer rather than an integer. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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4d86b1e7e1 |
srcu: Add SRCU_READ_FLAVOR_SLOWGP to flag need for synchronize_rcu()
This commit switches from a direct test of SRCU_READ_FLAVOR_LITE to a new SRCU_READ_FLAVOR_SLOWGP macro to check for substituting synchronize_rcu() for smp_mb() in SRCU grace periods. Right now, SRCU_READ_FLAVOR_SLOWGP is exactly SRCU_READ_FLAVOR_LITE, but the addition of the _fast() flavor of SRCU will change that. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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d31e31365b |
srcu: Force synchronization for srcu_get_delay()
Currently, srcu_get_delay() can be called concurrently, for example, by a CPU that is the first to request a new grace period and the CPU processing the current grace period. Although concurrent access is harmless, it unnecessarily expands the state space. Additionally, all calls to srcu_get_delay() are from slow paths. This commit therefore protects all calls to srcu_get_delay() with ssp->srcu_sup->lock, which is already held on the invocation from the srcu_funnel_gp_start() function. While in the area, this commit also adds a lockdep_assert_held() to srcu_get_delay() itself. Reported-by: syzbot+16a19b06125a2963eaee@syzkaller.appspotmail.com Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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821ca6fa15 |
srcu: Make Tree SRCU updates independent of ->srcu_idx
This commit makes Tree SRCU updates independent of ->srcu_idx, then drop ->srcu_idx. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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795e7efec6 |
srcu: Make SRCU readers use ->srcu_ctrs for counter selection
This commit causes SRCU readers to use ->srcu_ctrs for counter selection instead of ->srcu_idx. This takes another step towards array-indexing-free SRCU readers. [ paulmck: Apply kernel test robot feedback. ] Co-developed-by: Z qiang <qiang.zhang1211@gmail.com> Signed-off-by: Z qiang <qiang.zhang1211@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Tested-by: kernel test robot <oliver.sang@intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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56eb8be144 |
srcu: Pull ->srcu_{un,}lock_count into a new srcu_ctr structure
This commit prepares for array-index-free srcu_read_lock*() by moving the
->srcu_{un,}lock_count fields into a new srcu_ctr structure. This will
permit ->srcu_index to be replaced by a per-CPU pointer to this structure.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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Paul E. McKenney
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5f9e1bc50a |
srcu: Use ->srcu_gp_seq for rcutorture reader batch
This commit stops using ->srcu_idx for rcutorture's reader-batch
consistency checking, using ->srcu_gp_seq instead. This is a first
step towards a faster srcu_read_{,un}lock_lite() that avoids the array
accesses that use ->srcu_idx.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
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Paul E. McKenney
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da2ac56237 |
srcu: Make Tiny SRCU able to operate in preemptible kernels
Given that SRCU allows its read-side critical sections are not just preemptible, but also allow general blocking, there is not much reason to restrict Tiny SRCU to non-preemptible kernels. This commit therefore removes Tiny SRCU dependencies on non-preemptibility, primarily surrounding its interaction with rcutorture and early boot. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Ankur Arora <ankur.a.arora@oracle.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Kent Overstreet <kent.overstreet@linux.dev> Cc: <bpf@vger.kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Ankur Arora
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83b28cfe79 |
rcu: handle quiescent states for PREEMPT_RCU=n, PREEMPT_COUNT=y
With PREEMPT_RCU=n, cond_resched() provides urgently needed quiescent states for read-side critical sections via rcu_all_qs(). One reason why this was needed: lacking preempt-count, the tick handler has no way of knowing whether it is executing in a read-side critical section or not. With (PREEMPT_LAZY=y, PREEMPT_DYNAMIC=n), we get (PREEMPT_COUNT=y, PREEMPT_RCU=n). In this configuration cond_resched() is a stub and does not provide quiescent states via rcu_all_qs(). (PREEMPT_RCU=y provides this information via rcu_read_unlock() and its nesting counter.) So, use the availability of preempt_count() to report quiescent states in rcu_flavor_sched_clock_irq(). Suggested-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Ankur Arora
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fcf0e25ad4 |
rcu: handle unstable rdp in rcu_read_unlock_strict()
rcu_read_unlock_strict() can be called with preemption enabled which can make for an unstable rdp and a racy norm value. Fix this by dropping the preempt-count in __rcu_read_unlock() after the call to rcu_read_unlock_strict(), adjusting the preempt-count check appropriately. Suggested-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Ankur Arora
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4dca1af414 |
rcu: rename PREEMPT_AUTO to PREEMPT_LAZY
Replace mentions of PREEMPT_AUTO with PREEMPT_LAZY. Also, since PREMPT_LAZY implies PREEMPTION, we can reduce the TASKS_RCU selection criteria from this: NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO) to this: NEED_TASKS_RCU && PREEMPTION CC: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Vlastimil Babka
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49d5377b38 |
rcu, slab: use a regular callback function for kvfree_rcu
RCU has been special-casing callback function pointers that are integers lower than 4096 as offsets of rcu_head for kvfree() instead. The tree RCU implementation no longer does that as the batched kvfree_rcu() is not a simple call_rcu(). The tiny RCU still does, and the plan is also to make tree RCU use call_rcu() for SLUB_TINY configurations. Instead of teaching tree RCU again to special case the offsets, let's remove the special casing completely. Since there's no SLOB anymore, it is possible to create a callback function that can take a pointer to a middle of slab object with unknown offset and determine the object's pointer before freeing it, so implement that as kvfree_rcu_cb(). Large kmalloc and vmalloc allocations are handled simply by aligning down to page size. For that we retain the requirement that the offset is smaller than 4096. But we can remove __is_kvfree_rcu_offset() completely and instead just opencode the condition in the BUILD_BUG_ON() check. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Vlastimil Babka
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7f4b19ef31 |
rcu: remove trace_rcu_kvfree_callback
Tree RCU does not handle kvfree_rcu() by queueing individual objects by call_rcu() anymore, thus the tracepoint and associated __is_kvfree_rcu_offset() check is dead code now. Remove it. Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Vlastimil Babka
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b14ff274e8 |
slab, rcu: move TINY_RCU variant of kvfree_rcu() to SLAB
Following the move of TREE_RCU implementation, let's move also the TINY_RCU one for consistency and subsequent refactoring. For simplicity, remove the separate inline __kvfree_call_rcu() as TINY_RCU is not meant for high-performance hardware anyway. Declare kvfree_call_rcu() in rcupdate.h to avoid header dependency issues. Also move the kvfree_rcu_barrier() declaration to slab.h Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Tested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
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Zilin Guan
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764f6a8110 |
rcu: Remove READ_ONCE() for rdp->gpwrap access in __note_gp_changes()
There is one access to the per-CPU rdp->gpwrap field in the __note_gp_changes() function that does not use READ_ONCE(), but all other accesses do use READ_ONCE(). When using the 8*TREE03 and CONFIG_NR_CPUS=8 configuration, KCSAN found no data races at that point. This is because all calls to __note_gp_changes() hold rnp->lock, which excludes writes to the rdp->gpwrap fields for all CPUs associated with that same leaf rcu_node structure. This commit therefore removes READ_ONCE() from rdp->gpwrap accesses within the __note_gp_changes() function. Signed-off-by: Zilin Guan <zilinguan811@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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a3e8162105 |
rcu: Split rcu_report_exp_cpu_mult() mask parameter and use for tracing
This commit renames the rcu_report_exp_cpu_mult() function from "mask" to "mask_in" and introduced a "mask" local variable to better support upcoming event-tracing additions. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Cc: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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81a208c56e |
rcu: Clarify RCU_LAZY and RCU_LAZY_DEFAULT_OFF help text
This commit wordsmiths the RCU_LAZY and RCU_LAZY_DEFAULT_OFF Kconfig options' help text. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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053ca72554 |
rcu: Add CONFIG_RCU_LAZY delays to call_rcu() kernel-doc header
This commit adds a description of the energy-efficiency delays that call_rcu() can impose, along with a pointer to call_rcu_hurry() for latency-sensitive kernel code. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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366ba3f7f9 |
srcu: Point call_srcu() to call_rcu() for detailed memory ordering
This commit causes the call_srcu() kernel-doc header to reference that of call_rcu() for detailed memory-ordering guarantees. Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Paul E. McKenney
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21ef249862 |
rcu: Document self-propagating callbacks
This commit documents the fact that a given RCU callback function can repost itself. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> |
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Linus Torvalds
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9c5968db9e |
The various patchsets are summarized below. Plus of course many
indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec. - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones. - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest. - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code. - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups. - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code. - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c. - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator. - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading. - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated (https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/). Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED). - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled. - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL. - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests. - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size. - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic. - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated. - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated. - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed. - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic. - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy. - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic. - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions. - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed. - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting. - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface. - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior. - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi "introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors." - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram. - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal. - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance. - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation. - "Cleanup for memfd_create()" from Isaac Manjarres does that thing. - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration. - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices. - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests. -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQTTMBEPP41GrTpTJgfdBJ7gKXxAjgUCZ5a+cwAKCRDdBJ7gKXxA jtoyAP9R58oaOKPJuTizEKKXvh/RpMyD6sYcz/uPpnf+cKTZxQEAqfVznfWlw/Lz uC3KRZYhmd5YrxU4o+qjbzp9XWX/xAE= =Ib2s -----END PGP SIGNATURE----- Merge tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Pull MM updates from Andrew Morton: "The various patchsets are summarized below. Plus of course many indivudual patches which are described in their changelogs. - "Allocate and free frozen pages" from Matthew Wilcox reorganizes the page allocator so we end up with the ability to allocate and free zero-refcount pages. So that callers (ie, slab) can avoid a refcount inc & dec - "Support large folios for tmpfs" from Baolin Wang teaches tmpfs to use large folios other than PMD-sized ones - "Fix mm/rodata_test" from Petr Tesarik performs some maintenance and fixes for this small built-in kernel selftest - "mas_anode_descend() related cleanup" from Wei Yang tidies up part of the mapletree code - "mm: fix format issues and param types" from Keren Sun implements a few minor code cleanups - "simplify split calculation" from Wei Yang provides a few fixes and a test for the mapletree code - "mm/vma: make more mmap logic userland testable" from Lorenzo Stoakes continues the work of moving vma-related code into the (relatively) new mm/vma.c - "mm/page_alloc: gfp flags cleanups for alloc_contig_*()" from David Hildenbrand cleans up and rationalizes handling of gfp flags in the page allocator - "readahead: Reintroduce fix for improper RA window sizing" from Jan Kara is a second attempt at fixing a readahead window sizing issue. It should reduce the amount of unnecessary reading - "synchronously scan and reclaim empty user PTE pages" from Qi Zheng addresses an issue where "huge" amounts of pte pagetables are accumulated: https://lore.kernel.org/lkml/cover.1718267194.git.zhengqi.arch@bytedance.com/ Qi's series addresses this windup by synchronously freeing PTE memory within the context of madvise(MADV_DONTNEED) - "selftest/mm: Remove warnings found by adding compiler flags" from Muhammad Usama Anjum fixes some build warnings in the selftests code when optional compiler warnings are enabled - "mm: don't use __GFP_HARDWALL when migrating remote pages" from David Hildenbrand tightens the allocator's observance of __GFP_HARDWALL - "pkeys kselftests improvements" from Kevin Brodsky implements various fixes and cleanups in the MM selftests code, mainly pertaining to the pkeys tests - "mm/damon: add sample modules" from SeongJae Park enhances DAMON to estimate application working set size - "memcg/hugetlb: Rework memcg hugetlb charging" from Joshua Hahn provides some cleanups to memcg's hugetlb charging logic - "mm/swap_cgroup: remove global swap cgroup lock" from Kairui Song removes the global swap cgroup lock. A speedup of 10% for a tmpfs-based kernel build was demonstrated - "zram: split page type read/write handling" from Sergey Senozhatsky has several fixes and cleaups for zram in the area of zram_write_page(). A watchdog softlockup warning was eliminated - "move pagetable_*_dtor() to __tlb_remove_table()" from Kevin Brodsky cleans up the pagetable destructor implementations. A rare use-after-free race is fixed - "mm/debug: introduce and use VM_WARN_ON_VMG()" from Lorenzo Stoakes simplifies and cleans up the debugging code in the VMA merging logic - "Account page tables at all levels" from Kevin Brodsky cleans up and regularizes the pagetable ctor/dtor handling. This results in improvements in accounting accuracy - "mm/damon: replace most damon_callback usages in sysfs with new core functions" from SeongJae Park cleans up and generalizes DAMON's sysfs file interface logic - "mm/damon: enable page level properties based monitoring" from SeongJae Park increases the amount of information which is presented in response to DAMOS actions - "mm/damon: remove DAMON debugfs interface" from SeongJae Park removes DAMON's long-deprecated debugfs interfaces. Thus the migration to sysfs is completed - "mm/hugetlb: Refactor hugetlb allocation resv accounting" from Peter Xu cleans up and generalizes the hugetlb reservation accounting - "mm: alloc_pages_bulk: small API refactor" from Luiz Capitulino removes a never-used feature of the alloc_pages_bulk() interface - "mm/damon: extend DAMOS filters for inclusion" from SeongJae Park extends DAMOS filters to support not only exclusion (rejecting), but also inclusion (allowing) behavior - "Add zpdesc memory descriptor for zswap.zpool" from Alex Shi introduces a new memory descriptor for zswap.zpool that currently overlaps with struct page for now. This is part of the effort to reduce the size of struct page and to enable dynamic allocation of memory descriptors - "mm, swap: rework of swap allocator locks" from Kairui Song redoes and simplifies the swap allocator locking. A speedup of 400% was demonstrated for one workload. As was a 35% reduction for kernel build time with swap-on-zram - "mm: update mips to use do_mmap(), make mmap_region() internal" from Lorenzo Stoakes reworks MIPS's use of mmap_region() so that mmap_region() can be made MM-internal - "mm/mglru: performance optimizations" from Yu Zhao fixes a few MGLRU regressions and otherwise improves MGLRU performance - "Docs/mm/damon: add tuning guide and misc updates" from SeongJae Park updates DAMON documentation - "Cleanup for memfd_create()" from Isaac Manjarres does that thing - "mm: hugetlb+THP folio and migration cleanups" from David Hildenbrand provides various cleanups in the areas of hugetlb folios, THP folios and migration - "Uncached buffered IO" from Jens Axboe implements the new RWF_DONTCACHE flag which provides synchronous dropbehind for pagecache reading and writing. To permite userspace to address issues with massive buildup of useless pagecache when reading/writing fast devices - "selftests/mm: virtual_address_range: Reduce memory" from Thomas Weißschuh fixes and optimizes some of the MM selftests" * tag 'mm-stable-2025-01-26-14-59' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits) mm/compaction: fix UBSAN shift-out-of-bounds warning s390/mm: add missing ctor/dtor on page table upgrade kasan: sw_tags: use str_on_off() helper in kasan_init_sw_tags() tools: add VM_WARN_ON_VMG definition mm/damon/core: use str_high_low() helper in damos_wmark_wait_us() seqlock: add missing parameter documentation for raw_seqcount_try_begin() mm/page-writeback: consolidate wb_thresh bumping logic into __wb_calc_thresh mm/page_alloc: remove the incorrect and misleading comment zram: remove zcomp_stream_put() from write_incompressible_page() mm: separate move/undo parts from migrate_pages_batch() mm/kfence: use str_write_read() helper in get_access_type() selftests/mm/mkdirty: fix memory leak in test_uffdio_copy() kasan: hw_tags: Use str_on_off() helper in kasan_init_hw_tags() selftests/mm: virtual_address_range: avoid reading from VM_IO mappings selftests/mm: vm_util: split up /proc/self/smaps parsing selftests/mm: virtual_address_range: unmap chunks after validation selftests/mm: virtual_address_range: mmap() without PROT_WRITE selftests/memfd/memfd_test: fix possible NULL pointer dereference mm: add FGP_DONTCACHE folio creation flag mm: call filemap_fdatawrite_range_kick() after IOCB_DONTCACHE issue ... |
|
|
Linus Torvalds
|
1d6d399223 |
Kthreads affinity follow either of 4 existing different patterns:
1) Per-CPU kthreads must stay affine to a single CPU and never execute
relevant code on any other CPU. This is currently handled by smpboot
code which takes care of CPU-hotplug operations. Affinity here is
a correctness constraint.
2) Some kthreads _have_ to be affine to a specific set of CPUs and can't
run anywhere else. The affinity is set through kthread_bind_mask()
and the subsystem takes care by itself to handle CPU-hotplug
operations. Affinity here is assumed to be a correctness constraint.
3) Per-node kthreads _prefer_ to be affine to a specific NUMA node. This
is not a correctness constraint but merely a preference in terms of
memory locality. kswapd and kcompactd both fall into this category.
The affinity is set manually like for any other task and CPU-hotplug
is supposed to be handled by the relevant subsystem so that the task
is properly reaffined whenever a given CPU from the node comes up.
Also care should be taken so that the node affinity doesn't cross
isolated (nohz_full) cpumask boundaries.
4) Similar to the previous point except kthreads have a _preferred_
affinity different than a node. Both RCU boost kthreads and RCU
exp kworkers fall into this category as they refer to "RCU nodes"
from a distinctly distributed tree.
Currently the preferred affinity patterns (3 and 4) have at least 4
identified users, with more or less success when it comes to handle
CPU-hotplug operations and CPU isolation. Each of which do it in its own
ad-hoc way.
This is an infrastructure proposal to handle this with the following API
changes:
_ kthread_create_on_node() automatically affines the created kthread to
its target node unless it has been set as per-cpu or bound with
kthread_bind[_mask]() before the first wake-up.
- kthread_affine_preferred() is a new function that can be called right
after kthread_create_on_node() to specify a preferred affinity
different than the specified node.
When the preferred affinity can't be applied because the possible
targets are offline or isolated (nohz_full), the kthread is affine
to the housekeeping CPUs (which means to all online CPUs most of the
time or only the non-nohz_full CPUs when nohz_full= is set).
kswapd, kcompactd, RCU boost kthreads and RCU exp kworkers have been
converted, along with a few old drivers.
Summary of the changes:
* Consolidate a bunch of ad-hoc implementations of kthread_run_on_cpu()
* Introduce task_cpu_fallback_mask() that defines the default last
resort affinity of a task to become nohz_full aware
* Add some correctness check to ensure kthread_bind() is always called
before the first kthread wake up.
* Default affine kthread to its preferred node.
* Convert kswapd / kcompactd and remove their halfway working ad-hoc
affinity implementation
* Implement kthreads preferred affinity
* Unify kthread worker and kthread API's style
* Convert RCU kthreads to the new API and remove the ad-hoc affinity
implementation.
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Merge tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks
Pull kthread updates from Frederic Weisbecker:
"Kthreads affinity follow either of 4 existing different patterns:
1) Per-CPU kthreads must stay affine to a single CPU and never
execute relevant code on any other CPU. This is currently handled
by smpboot code which takes care of CPU-hotplug operations.
Affinity here is a correctness constraint.
2) Some kthreads _have_ to be affine to a specific set of CPUs and
can't run anywhere else. The affinity is set through
kthread_bind_mask() and the subsystem takes care by itself to
handle CPU-hotplug operations. Affinity here is assumed to be a
correctness constraint.
3) Per-node kthreads _prefer_ to be affine to a specific NUMA node.
This is not a correctness constraint but merely a preference in
terms of memory locality. kswapd and kcompactd both fall into this
category. The affinity is set manually like for any other task and
CPU-hotplug is supposed to be handled by the relevant subsystem so
that the task is properly reaffined whenever a given CPU from the
node comes up. Also care should be taken so that the node affinity
doesn't cross isolated (nohz_full) cpumask boundaries.
4) Similar to the previous point except kthreads have a _preferred_
affinity different than a node. Both RCU boost kthreads and RCU
exp kworkers fall into this category as they refer to "RCU nodes"
from a distinctly distributed tree.
Currently the preferred affinity patterns (3 and 4) have at least 4
identified users, with more or less success when it comes to handle
CPU-hotplug operations and CPU isolation. Each of which do it in its
own ad-hoc way.
This is an infrastructure proposal to handle this with the following
API changes:
- kthread_create_on_node() automatically affines the created kthread
to its target node unless it has been set as per-cpu or bound with
kthread_bind[_mask]() before the first wake-up.
- kthread_affine_preferred() is a new function that can be called
right after kthread_create_on_node() to specify a preferred
affinity different than the specified node.
When the preferred affinity can't be applied because the possible
targets are offline or isolated (nohz_full), the kthread is affine to
the housekeeping CPUs (which means to all online CPUs most of the time
or only the non-nohz_full CPUs when nohz_full= is set).
kswapd, kcompactd, RCU boost kthreads and RCU exp kworkers have been
converted, along with a few old drivers.
Summary of the changes:
- Consolidate a bunch of ad-hoc implementations of
kthread_run_on_cpu()
- Introduce task_cpu_fallback_mask() that defines the default last
resort affinity of a task to become nohz_full aware
- Add some correctness check to ensure kthread_bind() is always
called before the first kthread wake up.
- Default affine kthread to its preferred node.
- Convert kswapd / kcompactd and remove their halfway working ad-hoc
affinity implementation
- Implement kthreads preferred affinity
- Unify kthread worker and kthread API's style
- Convert RCU kthreads to the new API and remove the ad-hoc affinity
implementation"
* tag 'kthread-for-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks:
kthread: modify kernel-doc function name to match code
rcu: Use kthread preferred affinity for RCU exp kworkers
treewide: Introduce kthread_run_worker[_on_cpu]()
kthread: Unify kthread_create_on_cpu() and kthread_create_worker_on_cpu() automatic format
rcu: Use kthread preferred affinity for RCU boost
kthread: Implement preferred affinity
mm: Create/affine kswapd to its preferred node
mm: Create/affine kcompactd to its preferred node
kthread: Default affine kthread to its preferred NUMA node
kthread: Make sure kthread hasn't started while binding it
sched,arm64: Handle CPU isolation on last resort fallback rq selection
arm64: Exclude nohz_full CPUs from 32bits el0 support
lib: test_objpool: Use kthread_run_on_cpu()
kallsyms: Use kthread_run_on_cpu()
soc/qman: test: Use kthread_run_on_cpu()
arm/bL_switcher: Use kthread_run_on_cpu()
|
|
|
Linus Torvalds
|
9f3ee94e70 |
RCU pull request for v6.14
This pull request contains the following branches:
fixes.2024.12.14a: Misc fixes, check if IRQs are disabled in rcu_exp_need_qs(),
instrument KCSAN exclusive-writer assertions, add extra WARN_ON_ONCE() check,
set the cpu_no_qs.b.exp under lock, warn if callback enqueued on offline CPU.
rcutorture.2024.12.14a: Torture-test updates, add rcutorture.preempt_duration kernel
module parameter, make the TREE03 scenario do preemption, improve pooling timeouts
for rcu_torture_writer(), improve output of "Failure/close-call rcutorture reader
segments", add some reader-state debugging checks, update doc of polled APIs, add
extra diagnostics for per-reader-segment preemption.
srcu.2024.12.14a: SRCU updates, improve doc for srcu_read_lock() in terms of return
value, fix typo in comments, remove redundant GP sequence checks in the
srcu_funnel_gp_start.
torture-test.2024.12.14a: Add an extra test for sched_clock(), improve testing
on unresponsive systems.
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Merge tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux
Pull RCU updates from Uladzislau Rezki:
"Misc fixes:
- check if IRQs are disabled in rcu_exp_need_qs()
- instrument KCSAN exclusive-writer assertions
- add extra WARN_ON_ONCE() check
- set the cpu_no_qs.b.exp under lock
- warn if callback enqueued on offline CPU
Torture-test updates:
- add rcutorture.preempt_duration kernel module parameter
- make the TREE03 scenario do preemption
- improve pooling timeouts for rcu_torture_writer()
- improve output of "Failure/close-call rcutorture reader segments"
- add some reader-state debugging checks
- update doc of polled APIs
- add extra diagnostics for per-reader-segment preemption
- add an extra test for sched_clock()
- improve testing on unresponsive systems
SRCU updates:
- improve doc for srcu_read_lock() in terms of return value
- fix typo in comments
- remove redundant GP sequence checks in the srcu_funnel_gp_start"
* tag 'rcu.release.v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (31 commits)
srcu: Remove redundant GP sequence checks in srcu_funnel_gp_start
srcu: Fix typo s/srcu_check_read_flavor()/__srcu_check_read_flavor()/
srcu: Guarantee non-negative return value from srcu_read_lock()
MAINTAINERS: Update RCU git tree
rcu: Add lockdep_assert_irqs_disabled() to rcu_exp_need_qs()
rcu: Add KCSAN exclusive-writer assertions for rdp->cpu_no_qs.b.exp
rcu: Make preemptible rcu_exp_handler() check idempotency
rcu: Replace open-coded rcu_exp_need_qs() from rcu_exp_handler() with call
rcu: Move rcu_report_exp_rdp() setting of ->cpu_no_qs.b.exp under lock
rcu: Make rcu_report_exp_cpu_mult() caller acquire lock
rcu: Report callbacks enqueued on offline CPU blind spot
rcutorture: Use symbols for SRCU reader flavors
rcutorture: Add per-reader-segment preemption diagnostics
rcutorture: Read CPU ID for decoration protected by both reader types
rcutorture: Add preempt_count() to rcutorture_one_extend_check() diagnostics
rcutorture: Add parameters to control polled/conditional wait interval
rcutorture: Add documentation for recent conditional and polled APIs
rcutorture: Ignore attempts to test preemption and forward progress
rcutorture: Make rcutorture_one_extend() check reader state
rcutorture: Pretty-print rcutorture reader segments
...
|
|
Peter Zijlstra
|
d40797d672 |
kasan: make kasan_record_aux_stack_noalloc() the default behaviour
kasan_record_aux_stack_noalloc() was introduced to record a stack trace
without allocating memory in the process. It has been added to callers
which were invoked while a raw_spinlock_t was held. More and more callers
were identified and changed over time. Is it a good thing to have this
while functions try their best to do a locklessly setup? The only
downside of having kasan_record_aux_stack() not allocate any memory is
that we end up without a stacktrace if stackdepot runs out of memory and
at the same stacktrace was not recorded before To quote Marco Elver from
https://lore.kernel.org/all/CANpmjNPmQYJ7pv1N3cuU8cP18u7PP_uoZD8YxwZd4jtbof9nVQ@mail.gmail.com/
| I'd be in favor, it simplifies things. And stack depot should be
| able to replenish its pool sufficiently in the "non-aux" cases
| i.e. regular allocations. Worst case we fail to record some
| aux stacks, but I think that's only really bad if there's a bug
| around one of these allocations. In general the probabilities
| of this being a regression are extremely small [...]
Make the kasan_record_aux_stack_noalloc() behaviour default as
kasan_record_aux_stack().
[bigeasy@linutronix.de: dressed the diff as patch]
Link: https://lkml.kernel.org/r/20241122155451.Mb2pmeyJ@linutronix.de
Fixes:
|
|
|
Uladzislau Rezki (Sony)
|
bbe658d658 |
mm/slab: Move kvfree_rcu() into SLAB
Move kvfree_rcu() functionality to the slab_common.c file. The reason to have kvfree_rcu() functionality as part of SLAB is that there is a clear trend and need of closer integration. One of the recent example is creating a barrier function for SLAB caches. Another reason is to prevent of having several implementations of RCU machinery for reclaiming objects after a GP. As future steps, it can be more integrated(easier) with SLAB internals. Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com> Tested-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |
|
|
Uladzislau Rezki (Sony)
|
c18bcd85ce |
rcu/kvfree: Adjust a shrinker name
Rename "rcu-kfree" to "slab-kvfree-rcu" since it goes to the slab_common.c file soon. Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> Acked-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com> Tested-by: Hyeonggon Yoo <hyeonggon.yoo@sk.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> |