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8f7c8b88bd
4366 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Linus Torvalds
|
8f7c8b88bd |
sched_ext: Change for v6.13
- Improve the default select_cpu() implementation making it topology aware
and handle WAKE_SYNC better.
- set_arg_maybe_null() was used to inform the verifier which ops args could
be NULL in a rather hackish way. Use the new __nullable CFI stub tags
instead.
- On Sapphire Rapids multi-socket systems, a BPF scheduler, by hammering on
the same queue across sockets, could live-lock the system to the point
where the system couldn't make reasonable forward progress. This could
lead to soft-lockup triggered resets or stalling out bypass mode switch
and thus BPF scheduler ejection for tens of minutes if not hours. After
trying a number of mitigations, the following set worked reliably:
- Injecting artificial cpu_relax() loops in two places while sched_ext is
trying to turn on the bypass mode.
- Triggering scheduler ejection when soft-lockup detection is imminent (a
quarter of threshold left).
While not the prettiest, the impact both in terms of code complexity and
overhead is minimal.
- A common complaint on the API is the overuse of the word "dispatch" and
the confusion around "consume". This is due to how the dispatch queues
became more generic over time. Rename the affected kfuncs for clarity.
Thanks to BPF's compatibility features, this change can be made in a way
that's both forward and backward compatible. The compatibility code will
be dropped in a few releases.
- Pull sched_ext/for-6.12-fixes to receive a prerequisite change. Other misc
changes.
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Merge tag 'sched_ext-for-6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext updates from Tejun Heo:
- Improve the default select_cpu() implementation making it topology
aware and handle WAKE_SYNC better.
- set_arg_maybe_null() was used to inform the verifier which ops args
could be NULL in a rather hackish way. Use the new __nullable CFI
stub tags instead.
- On Sapphire Rapids multi-socket systems, a BPF scheduler, by
hammering on the same queue across sockets, could live-lock the
system to the point where the system couldn't make reasonable forward
progress.
This could lead to soft-lockup triggered resets or stalling out
bypass mode switch and thus BPF scheduler ejection for tens of
minutes if not hours. After trying a number of mitigations, the
following set worked reliably:
- Injecting artificial cpu_relax() loops in two places while
sched_ext is trying to turn on the bypass mode.
- Triggering scheduler ejection when soft-lockup detection is
imminent (a quarter of threshold left).
While not the prettiest, the impact both in terms of code complexity
and overhead is minimal.
- A common complaint on the API is the overuse of the word "dispatch"
and the confusion around "consume". This is due to how the dispatch
queues became more generic over time. Rename the affected kfuncs for
clarity. Thanks to BPF's compatibility features, this change can be
made in a way that's both forward and backward compatible. The
compatibility code will be dropped in a few releases.
- Other misc changes
* tag 'sched_ext-for-6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (21 commits)
sched_ext: Replace scx_next_task_picked() with switch_class() in comment
sched_ext: Rename scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()
sched_ext: Rename scx_bpf_consume() to scx_bpf_dsq_move_to_local()
sched_ext: Rename scx_bpf_dispatch[_vtime]() to scx_bpf_dsq_insert[_vtime]()
sched_ext: scx_bpf_dispatch_from_dsq_set_*() are allowed from unlocked context
sched_ext: add a missing rcu_read_lock/unlock pair at scx_select_cpu_dfl()
sched_ext: Clarify sched_ext_ops table for userland scheduler
sched_ext: Enable the ops breather and eject BPF scheduler on softlockup
sched_ext: Avoid live-locking bypass mode switching
sched_ext: Fix incorrect use of bitwise AND
sched_ext: Do not enable LLC/NUMA optimizations when domains overlap
sched_ext: Introduce NUMA awareness to the default idle selection policy
sched_ext: Replace set_arg_maybe_null() with __nullable CFI stub tags
sched_ext: Rename CFI stubs to names that are recognized by BPF
sched_ext: Introduce LLC awareness to the default idle selection policy
sched_ext: Clarify ops.select_cpu() for single-CPU tasks
sched_ext: improve WAKE_SYNC behavior for default idle CPU selection
sched_ext: Use btf_ids to resolve task_struct
sched/ext: Use tg_cgroup() to elieminate duplicate code
sched/ext: Fix unmatch trailing comment of CONFIG_EXT_GROUP_SCHED
...
|
||
|
Linus Torvalds
|
bf9aa14fc5 |
A rather large update for timekeeping and timers:
- The final step to get rid of auto-rearming posix-timers
posix-timers are currently auto-rearmed by the kernel when the signal
of the timer is ignored so that the timer signal can be delivered once
the corresponding signal is unignored.
This requires to throttle the timer to prevent a DoS by small intervals
and keeps the system pointlessly out of low power states for no value.
This is a long standing non-trivial problem due to the lock order of
posix-timer lock and the sighand lock along with life time issues as
the timer and the sigqueue have different life time rules.
Cure this by:
* Embedding the sigqueue into the timer struct to have the same life
time rules. Aside of that this also avoids the lookup of the timer
in the signal delivery and rearm path as it's just a always valid
container_of() now.
* Queuing ignored timer signals onto a seperate ignored list.
* Moving queued timer signals onto the ignored list when the signal is
switched to SIG_IGN before it could be delivered.
* Walking the ignored list when SIG_IGN is lifted and requeue the
signals to the actual signal lists. This allows the signal delivery
code to rearm the timer.
This also required to consolidate the signal delivery rules so they are
consistent across all situations. With that all self test scenarios
finally succeed.
- Core infrastructure for VFS multigrain timestamping
This is required to allow the kernel to use coarse grained time stamps
by default and switch to fine grained time stamps when inode attributes
are actively observed via getattr().
These changes have been provided to the VFS tree as well, so that the
VFS specific infrastructure could be built on top.
- Cleanup and consolidation of the sleep() infrastructure
* Move all sleep and timeout functions into one file
* Rework udelay() and ndelay() into proper documented inline functions
and replace the hardcoded magic numbers by proper defines.
* Rework the fsleep() implementation to take the reality of the timer
wheel granularity on different HZ values into account. Right now the
boundaries are hard coded time ranges which fail to provide the
requested accuracy on different HZ settings.
* Update documentation for all sleep/timeout related functions and fix
up stale documentation links all over the place
* Fixup a few usage sites
- Rework of timekeeping and adjtimex(2) to prepare for multiple PTP clocks
A system can have multiple PTP clocks which are participating in
seperate and independent PTP clock domains. So far the kernel only
considers the PTP clock which is based on CLOCK TAI relevant as that's
the clock which drives the timekeeping adjustments via the various user
space daemons through adjtimex(2).
The non TAI based clock domains are accessible via the file descriptor
based posix clocks, but their usability is very limited. They can't be
accessed fast as they always go all the way out to the hardware and
they cannot be utilized in the kernel itself.
As Time Sensitive Networking (TSN) gains traction it is required to
provide fast user and kernel space access to these clocks.
The approach taken is to utilize the timekeeping and adjtimex(2)
infrastructure to provide this access in a similar way how the kernel
provides access to clock MONOTONIC, REALTIME etc.
Instead of creating a duplicated infrastructure this rework converts
timekeeping and adjtimex(2) into generic functionality which operates
on pointers to data structures instead of using static variables.
This allows to provide time accessors and adjtimex(2) functionality for
the independent PTP clocks in a subsequent step.
- Consolidate hrtimer initialization
hrtimers are set up by initializing the data structure and then
seperately setting the callback function for historical reasons.
That's an extra unnecessary step and makes Rust support less straight
forward than it should be.
Provide a new set of hrtimer_setup*() functions and convert the core
code and a few usage sites of the less frequently used interfaces over.
The bulk of the htimer_init() to hrtimer_setup() conversion is already
prepared and scheduled for the next merge window.
- Drivers:
* Ensure that the global timekeeping clocksource is utilizing the
cluster 0 timer on MIPS multi-cluster systems.
Otherwise CPUs on different clusters use their cluster specific
clocksource which is not guaranteed to be synchronized with other
clusters.
* Mostly boring cleanups, fixes, improvements and code movement
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Merge tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer updates from Thomas Gleixner:
"A rather large update for timekeeping and timers:
- The final step to get rid of auto-rearming posix-timers
posix-timers are currently auto-rearmed by the kernel when the
signal of the timer is ignored so that the timer signal can be
delivered once the corresponding signal is unignored.
This requires to throttle the timer to prevent a DoS by small
intervals and keeps the system pointlessly out of low power states
for no value. This is a long standing non-trivial problem due to
the lock order of posix-timer lock and the sighand lock along with
life time issues as the timer and the sigqueue have different life
time rules.
Cure this by:
- Embedding the sigqueue into the timer struct to have the same
life time rules. Aside of that this also avoids the lookup of
the timer in the signal delivery and rearm path as it's just a
always valid container_of() now.
- Queuing ignored timer signals onto a seperate ignored list.
- Moving queued timer signals onto the ignored list when the
signal is switched to SIG_IGN before it could be delivered.
- Walking the ignored list when SIG_IGN is lifted and requeue the
signals to the actual signal lists. This allows the signal
delivery code to rearm the timer.
This also required to consolidate the signal delivery rules so they
are consistent across all situations. With that all self test
scenarios finally succeed.
- Core infrastructure for VFS multigrain timestamping
This is required to allow the kernel to use coarse grained time
stamps by default and switch to fine grained time stamps when inode
attributes are actively observed via getattr().
These changes have been provided to the VFS tree as well, so that
the VFS specific infrastructure could be built on top.
- Cleanup and consolidation of the sleep() infrastructure
- Move all sleep and timeout functions into one file
- Rework udelay() and ndelay() into proper documented inline
functions and replace the hardcoded magic numbers by proper
defines.
- Rework the fsleep() implementation to take the reality of the
timer wheel granularity on different HZ values into account.
Right now the boundaries are hard coded time ranges which fail
to provide the requested accuracy on different HZ settings.
- Update documentation for all sleep/timeout related functions
and fix up stale documentation links all over the place
- Fixup a few usage sites
- Rework of timekeeping and adjtimex(2) to prepare for multiple PTP
clocks
A system can have multiple PTP clocks which are participating in
seperate and independent PTP clock domains. So far the kernel only
considers the PTP clock which is based on CLOCK TAI relevant as
that's the clock which drives the timekeeping adjustments via the
various user space daemons through adjtimex(2).
The non TAI based clock domains are accessible via the file
descriptor based posix clocks, but their usability is very limited.
They can't be accessed fast as they always go all the way out to
the hardware and they cannot be utilized in the kernel itself.
As Time Sensitive Networking (TSN) gains traction it is required to
provide fast user and kernel space access to these clocks.
The approach taken is to utilize the timekeeping and adjtimex(2)
infrastructure to provide this access in a similar way how the
kernel provides access to clock MONOTONIC, REALTIME etc.
Instead of creating a duplicated infrastructure this rework
converts timekeeping and adjtimex(2) into generic functionality
which operates on pointers to data structures instead of using
static variables.
This allows to provide time accessors and adjtimex(2) functionality
for the independent PTP clocks in a subsequent step.
- Consolidate hrtimer initialization
hrtimers are set up by initializing the data structure and then
seperately setting the callback function for historical reasons.
That's an extra unnecessary step and makes Rust support less
straight forward than it should be.
Provide a new set of hrtimer_setup*() functions and convert the
core code and a few usage sites of the less frequently used
interfaces over.
The bulk of the htimer_init() to hrtimer_setup() conversion is
already prepared and scheduled for the next merge window.
- Drivers:
- Ensure that the global timekeeping clocksource is utilizing the
cluster 0 timer on MIPS multi-cluster systems.
Otherwise CPUs on different clusters use their cluster specific
clocksource which is not guaranteed to be synchronized with
other clusters.
- Mostly boring cleanups, fixes, improvements and code movement"
* tag 'timers-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (140 commits)
posix-timers: Fix spurious warning on double enqueue versus do_exit()
clocksource/drivers/arm_arch_timer: Use of_property_present() for non-boolean properties
clocksource/drivers/gpx: Remove redundant casts
clocksource/drivers/timer-ti-dm: Fix child node refcount handling
dt-bindings: timer: actions,owl-timer: convert to YAML
clocksource/drivers/ralink: Add Ralink System Tick Counter driver
clocksource/drivers/mips-gic-timer: Always use cluster 0 counter as clocksource
clocksource/drivers/timer-ti-dm: Don't fail probe if int not found
clocksource/drivers:sp804: Make user selectable
clocksource/drivers/dw_apb: Remove unused dw_apb_clockevent functions
hrtimers: Delete hrtimer_init_on_stack()
alarmtimer: Switch to use hrtimer_setup() and hrtimer_setup_on_stack()
io_uring: Switch to use hrtimer_setup_on_stack()
sched/idle: Switch to use hrtimer_setup_on_stack()
hrtimers: Delete hrtimer_init_sleeper_on_stack()
wait: Switch to use hrtimer_setup_sleeper_on_stack()
timers: Switch to use hrtimer_setup_sleeper_on_stack()
net: pktgen: Switch to use hrtimer_setup_sleeper_on_stack()
futex: Switch to use hrtimer_setup_sleeper_on_stack()
fs/aio: Switch to use hrtimer_setup_sleeper_on_stack()
...
|
||
|
Linus Torvalds
|
3f020399e4 |
Scheduler changes for v6.13:
- Core facilities:
- Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which optimizes
fair-class preemption by delaying preemption requests to the
tick boundary, while working as full preemption for RR/FIFO/DEADLINE
classes. (Peter Zijlstra)
- x86: Enable Lazy preemption (Peter Zijlstra)
- riscv: Enable Lazy preemption (Jisheng Zhang)
- Initialize idle tasks only once (Thomas Gleixner)
- sched/ext: Remove sched_fork() hack (Thomas Gleixner)
- Fair scheduler:
- Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)
- Idle loop:
Optimize the generic idle loop by removing unnecessary
memory barrier (Zhongqiu Han)
- RSEQ:
- Improve cache locality of RSEQ concurrency IDs for
intermittent workloads (Mathieu Desnoyers)
- Waitqueues:
- Make wake_up_{bit,var} less fragile (Neil Brown)
- PSI:
- Pass enqueue/dequeue flags to psi callbacks directly (Johannes Weiner)
- Preparatory patches for proxy execution:
- core: Add move_queued_task_locked helper (Connor O'Brien)
- core: Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)
- core: Split out __schedule() deactivate task logic into a helper (John Stultz)
- core: Split scheduler and execution contexts (Peter Zijlstra)
- locking/mutex: Make mutex::wait_lock irq safe (Juri Lelli)
- locking/mutex: Expose __mutex_owner() (Juri Lelli)
- locking/mutex: Remove wakeups from under mutex::wait_lock (Peter Zijlstra)
- Misc fixes and cleanups:
- core: Remove unused __HAVE_THREAD_FUNCTIONS hook support (David Disseldorp)
- core: Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej Siewior)
- wait: Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)
- fair: remove the DOUBLE_TICK feature (Huang Shijie)
- fair: fix the comment for PREEMPT_SHORT (Huang Shijie)
- uclamp: Fix unnused variable warning (Christian Loehle)
- rt: No PREEMPT_RT=y for all{yes,mod}config
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"Core facilities:
- Add the "Lazy preemption" model (CONFIG_PREEMPT_LAZY=y), which
optimizes fair-class preemption by delaying preemption requests to
the tick boundary, while working as full preemption for
RR/FIFO/DEADLINE classes. (Peter Zijlstra)
- x86: Enable Lazy preemption (Peter Zijlstra)
- riscv: Enable Lazy preemption (Jisheng Zhang)
- Initialize idle tasks only once (Thomas Gleixner)
- sched/ext: Remove sched_fork() hack (Thomas Gleixner)
Fair scheduler:
- Optimize the PLACE_LAG when se->vlag is zero (Huang Shijie)
Idle loop:
- Optimize the generic idle loop by removing unnecessary memory
barrier (Zhongqiu Han)
RSEQ:
- Improve cache locality of RSEQ concurrency IDs for intermittent
workloads (Mathieu Desnoyers)
Waitqueues:
- Make wake_up_{bit,var} less fragile (Neil Brown)
PSI:
- Pass enqueue/dequeue flags to psi callbacks directly (Johannes
Weiner)
Preparatory patches for proxy execution:
- Add move_queued_task_locked helper (Connor O'Brien)
- Consolidate pick_*_task to task_is_pushable helper (Connor O'Brien)
- Split out __schedule() deactivate task logic into a helper (John
Stultz)
- Split scheduler and execution contexts (Peter Zijlstra)
- Make mutex::wait_lock irq safe (Juri Lelli)
- Expose __mutex_owner() (Juri Lelli)
- Remove wakeups from under mutex::wait_lock (Peter Zijlstra)
Misc fixes and cleanups:
- Remove unused __HAVE_THREAD_FUNCTIONS hook support (David
Disseldorp)
- Update the comment for TIF_NEED_RESCHED_LAZY (Sebastian Andrzej
Siewior)
- Remove unused bit_wait_io_timeout (Dr. David Alan Gilbert)
- remove the DOUBLE_TICK feature (Huang Shijie)
- fix the comment for PREEMPT_SHORT (Huang Shijie)
- Fix unnused variable warning (Christian Loehle)
- No PREEMPT_RT=y for all{yes,mod}config"
* tag 'sched-core-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
sched, x86: Update the comment for TIF_NEED_RESCHED_LAZY.
sched: No PREEMPT_RT=y for all{yes,mod}config
riscv: add PREEMPT_LAZY support
sched, x86: Enable Lazy preemption
sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT
sched: Add Lazy preemption model
sched: Add TIF_NEED_RESCHED_LAZY infrastructure
sched/ext: Remove sched_fork() hack
sched: Initialize idle tasks only once
sched: psi: pass enqueue/dequeue flags to psi callbacks directly
sched/uclamp: Fix unnused variable warning
sched: Split scheduler and execution contexts
sched: Split out __schedule() deactivate task logic into a helper
sched: Consolidate pick_*_task to task_is_pushable helper
sched: Add move_queued_task_locked helper
locking/mutex: Expose __mutex_owner()
locking/mutex: Make mutex::wait_lock irq safe
locking/mutex: Remove wakeups from under mutex::wait_lock
sched: Improve cache locality of RSEQ concurrency IDs for intermittent workloads
sched: idle: Optimize the generic idle loop by removing needless memory barrier
...
|
||
|
Linus Torvalds
|
ad52c55e1d |
Power management updates for 6.13-rc1
- Update the amd-pstate driver to set the initial scaling frequency
policy lower bound to be the lowest non-linear frequency (Dhananjay
Ugwekar).
- Enable amd-pstate by default on servers starting with newer AMD Epyc
processors (Swapnil Sapkal).
- Align more codepaths between shared memory and MSR designs in
amd-pstate (Dhananjay Ugwekar).
- Clean up amd-pstate code to rename functions and remove redundant
calls (Dhananjay Ugwekar, Mario Limonciello).
- Do other assorted fixes and cleanups in amd-pstate (Dhananjay Ugwekar
and Mario Limonciello).
- Change the Balance-performance EPP value for Granite Rapids in the
intel_pstate driver to a more performance-biased one (Srinivas
Pandruvada).
- Simplify MSR read on the boot CPU in the ACPI cpufreq driver (Chang
S. Bae).
- Ensure sugov_eas_rebuild_sd() is always called when sugov_init()
succeeds to always enforce sched domains rebuild in case EAS needs
to be enabled (Christian Loehle).
- Switch cpufreq back to platform_driver::remove() (Uwe Kleine-König).
- Use proper frequency unit names in cpufreq (Marcin Juszkiewicz).
- Add a built-in idle states table for Granite Rapids Xeon D to the
intel_idle driver (Artem Bityutskiy).
- Fix some typos in comments in the cpuidle core and drivers (Shen
Lichuan).
- Remove iowait influence from the menu cpuidle governor (Christian
Loehle).
- Add min/max available performance state limits to the Energy Model
management code (Lukasz Luba).
- Update pm-graph to v5.13 (Todd Brandt).
- Add documentation for some recently introduced cpupower utility
options (Tor Vic).
- Make cpupower inform users where cpufreq-bench.conf should be located
when opening it fails (Peng Fan).
- Allow overriding cross-compiling env params in cpupower (Peng Fan).
- Add compile_commands.json to .gitignore in cpupower (John B. Wyatt
IV).
- Improve disable c_state block in cpupower bindings and add a test to
confirm that CPU state is disabled to it (John B. Wyatt IV).
- Add Chinese Simplified translation to cpupower (Kieran Moy).
- Add checks for xgettext and msgfmt to cpupower (Siddharth Menon).
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Merge tag 'pm-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"The amd-pstate cpufreq driver gets the majority of changes this time.
They are mostly fixes and cleanups, but one of them causes it to
become the default cpufreq driver on some AMD server platforms.
Apart from that, the menu cpuidle governor is modified to not use
iowait any more, the intel_idle gets a custom C-states table for
Granite Rapids Xeon D, and the intel_pstate driver will use a more
aggressive Balance- performance default EPP value on Granite Rapids
now.
There are also some fixes, cleanups and tooling updates.
Specifics:
- Update the amd-pstate driver to set the initial scaling frequency
policy lower bound to be the lowest non-linear frequency (Dhananjay
Ugwekar)
- Enable amd-pstate by default on servers starting with newer AMD
Epyc processors (Swapnil Sapkal)
- Align more codepaths between shared memory and MSR designs in
amd-pstate (Dhananjay Ugwekar)
- Clean up amd-pstate code to rename functions and remove redundant
calls (Dhananjay Ugwekar, Mario Limonciello)
- Do other assorted fixes and cleanups in amd-pstate (Dhananjay
Ugwekar and Mario Limonciello)
- Change the Balance-performance EPP value for Granite Rapids in the
intel_pstate driver to a more performance-biased one (Srinivas
Pandruvada)
- Simplify MSR read on the boot CPU in the ACPI cpufreq driver (Chang
S. Bae)
- Ensure sugov_eas_rebuild_sd() is always called when sugov_init()
succeeds to always enforce sched domains rebuild in case EAS needs
to be enabled (Christian Loehle)
- Switch cpufreq back to platform_driver::remove() (Uwe Kleine-König)
- Use proper frequency unit names in cpufreq (Marcin Juszkiewicz)
- Add a built-in idle states table for Granite Rapids Xeon D to the
intel_idle driver (Artem Bityutskiy)
- Fix some typos in comments in the cpuidle core and drivers (Shen
Lichuan)
- Remove iowait influence from the menu cpuidle governor (Christian
Loehle)
- Add min/max available performance state limits to the Energy Model
management code (Lukasz Luba)
- Update pm-graph to v5.13 (Todd Brandt)
- Add documentation for some recently introduced cpupower utility
options (Tor Vic)
- Make cpupower inform users where cpufreq-bench.conf should be
located when opening it fails (Peng Fan)
- Allow overriding cross-compiling env params in cpupower (Peng Fan)
- Add compile_commands.json to .gitignore in cpupower (John B. Wyatt
IV)
- Improve disable c_state block in cpupower bindings and add a test
to confirm that CPU state is disabled to it (John B. Wyatt IV)
- Add Chinese Simplified translation to cpupower (Kieran Moy)
- Add checks for xgettext and msgfmt to cpupower (Siddharth Menon)"
* tag 'pm-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (38 commits)
cpufreq: intel_pstate: Update Balance-performance EPP for Granite Rapids
cpufreq: ACPI: Simplify MSR read on the boot CPU
sched/cpufreq: Ensure sd is rebuilt for EAS check
intel_idle: add Granite Rapids Xeon D support
PM: EM: Add min/max available performance state limits
cpufreq/amd-pstate: Move registration after static function call update
cpufreq/amd-pstate: Push adjust_perf vfunc init into cpu_init
cpufreq/amd-pstate: Align offline flow of shared memory and MSR based systems
cpufreq/amd-pstate: Call cppc_set_epp_perf in the reenable function
cpufreq/amd-pstate: Do not attempt to clear MSR_AMD_CPPC_ENABLE
cpufreq/amd-pstate: Rename functions that enable CPPC
cpufreq/amd-pstate-ut: Add fix for min freq unit test
amd-pstate: Switch to amd-pstate by default on some Server platforms
amd-pstate: Set min_perf to nominal_perf for active mode performance gov
cpufreq/amd-pstate: Remove the redundant amd_pstate_set_driver() call
cpufreq/amd-pstate: Remove the switch case in amd_pstate_init()
cpufreq/amd-pstate: Call amd_pstate_set_driver() in amd_pstate_register_driver()
cpufreq/amd-pstate: Call amd_pstate_register() in amd_pstate_init()
cpufreq/amd-pstate: Set the initial min_freq to lowest_nonlinear_freq
cpufreq/amd-pstate: Remove the redundant verify() function
...
|
||
|
Linus Torvalds
|
a5ca574796 |
vfs-6.13.usercopy
-----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRAhzRXHqcMeLMyaSiRxhvAZXjcogUCZzchMwAKCRCRxhvAZXjc okICAP4h6tDl7dgTv8GkL0tgaHi/36m+ilctXbEtIe9fbkc/fQD8D5t6jYaz47gu zVY7qOrtQOQ/diNavzxyky99Uh3dKgo= =lwkw -----END PGP SIGNATURE----- Merge tag 'vfs-6.13.usercopy' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull copy_struct_to_user helper from Christian Brauner: "This adds a copy_struct_to_user() helper which is a companion helper to the already widely used copy_struct_from_user(). It copies a struct from kernel space to userspace, in a way that guarantees backwards-compatibility for struct syscall arguments as long as future struct extensions are made such that all new fields are appended to the old struct, and zeroed-out new fields have the same meaning as the old struct. The first user is sched_getattr() system call but the new extensible pidfs ioctl will be ported to it as well" * tag 'vfs-6.13.usercopy' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: sched_getattr: port to copy_struct_to_user uaccess: add copy_struct_to_user helper |
||
|
Linus Torvalds
|
d79944b094 |
sched_ext: One more fix for v6.12-rc7
ops.cpu_acquire() was being invoked with the wrong kfunc mask allowing the operation to call kfuncs which shouldn't be allowed. Fix it by using SCX_KF_REST instead, which is trivial and low risk. -----BEGIN PGP SIGNATURE----- iIQEABYKACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCZzamXw4cdGpAa2VybmVs Lm9yZwAKCRCxYfJx3gVYGRReAP4/JQ1mKkJv+9nTZkW9OcFFHGVVhrprOUEEFk5j pmHwPAD8DTBMMS/BCQOoXDdiB9uU7ut6M8VdsIj1jmJkMja+eQI= =942J -----END PGP SIGNATURE----- Merge tag 'sched_ext-for-6.12-rc7-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fix from Tejun Heo: "One more fix for v6.12-rc7 ops.cpu_acquire() was being invoked with the wrong kfunc mask allowing the operation to call kfuncs which shouldn't be allowed. Fix it by using SCX_KF_REST instead, which is trivial and low risk" * tag 'sched_ext-for-6.12-rc7-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: ops.cpu_acquire() should be called with SCX_KF_REST |
||
Zhao Mengmeng
|
6b8950ef99 |
sched_ext: Replace scx_next_task_picked() with switch_class() in comment
scx_next_task_picked() has been replaced with siwtch_class(), but comment is still referencing old one, so replace it. Signed-off-by: Zhao Mengmeng <zhaomengmeng@kylinos.cn> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
Tejun Heo
|
a4af89cc50 |
sched_ext: ops.cpu_acquire() should be called with SCX_KF_REST
ops.cpu_acquire() is currently called with 0 kf_maks which is interpreted as
SCX_KF_UNLOCKED which allows all unlocked kfuncs, but ops.cpu_acquire() is
called from balance_one() under the rq lock and should only be allowed call
kfuncs that are safe under the rq lock. Update it to use SCX_KF_REST.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: David Vernet <void@manifault.com>
Cc: Zhao Mengmeng <zhaomzhao@126.com>
Link: http://lkml.kernel.org/r/ZzYvf2L3rlmjuKzh@slm.duckdns.org
Fixes:
|
||
Christian Loehle
|
70d8b6485b |
sched/cpufreq: Ensure sd is rebuilt for EAS check
Ensure sugov_eas_rebuild_sd() is always called when sugov_init()
succeeds. The out goto initialized sugov without forcing the rebuild.
Previously the missing call to sugov_eas_rebuild_sd() could lead to EAS
not being enabled on boot when it should have been, because it requires
all policies to be controlled by schedutil while they might not have
been initialized yet.
Fixes:
|
||
|
Linus Torvalds
|
3022e9d00e |
sched_ext: Fixes for v6.12-rc7
- The fair sched class currently has a bug where its balance() returns true telling the sched core that it has tasks to run but then NULL from pick_task(). This makes sched core call sched_ext's pick_task() without preceding balance() which can lead to stalls in partial mode. For now, work around by detecting the condition and forcing the CPU to go through another scheduling cycle. - Add a missing newline to an error message and fix drgn introspection tool which went out of sync. -----BEGIN PGP SIGNATURE----- iIQEABYKACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCZzI8sw4cdGpAa2VybmVs Lm9yZwAKCRCxYfJx3gVYGb5KAP40b/o6TyAFDG+Hn6GxyxQT7rcAUMXsdB2bcEpg /IjmzQEAwbHU5KP5vQXV6XHv+2V7Rs7u6ZqFtDnL88N0A9hf3wk= =7hL8 -----END PGP SIGNATURE----- Merge tag 'sched_ext-for-6.12-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: - The fair sched class currently has a bug where its balance() returns true telling the sched core that it has tasks to run but then NULL from pick_task(). This makes sched core call sched_ext's pick_task() without preceding balance() which can lead to stalls in partial mode. For now, work around by detecting the condition and forcing the CPU to go through another scheduling cycle. - Add a missing newline to an error message and fix drgn introspection tool which went out of sync. * tag 'sched_ext-for-6.12-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx() sched_ext: Update scx_show_state.py to match scx_ops_bypass_depth's new type sched_ext: Add a missing newline at the end of an error message |
||
|
Tejun Heo
|
5cbb302880 |
sched_ext: Rename scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*()
In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the third set of renames. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. - scx_bpf_dispatch[_vtime]_from_dsq*() were already wrapped in __COMPAT macros as they were introduced during v6.12 cycle. Wrap new API in __COMPAT macros too and trigger build errors on both __COMPAT prefixed and naked usages of the old names. The compat features will be dropped after v6.15. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Andrea Righi <arighi@nvidia.com> Acked-by: Changwoo Min <changwoo@igalia.com> Acked-by: Johannes Bechberger <me@mostlynerdless.de> Acked-by: Giovanni Gherdovich <ggherdovich@suse.com> Cc: Dan Schatzberg <dschatzberg@meta.com> Cc: Ming Yang <yougmark94@gmail.com> |
||
|
Tejun Heo
|
5209c03c8e |
sched_ext: Rename scx_bpf_consume() to scx_bpf_dsq_move_to_local()
In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the second rename. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. The compat features will be dropped after v6.15. v2: Comment and documentation updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Andrea Righi <arighi@nvidia.com> Acked-by: Changwoo Min <changwoo@igalia.com> Acked-by: Johannes Bechberger <me@mostlynerdless.de> Acked-by: Giovanni Gherdovich <ggherdovich@suse.com> Cc: Dan Schatzberg <dschatzberg@meta.com> Cc: Ming Yang <yougmark94@gmail.com> |
||
|
Tejun Heo
|
cc26abb1a1 |
sched_ext: Rename scx_bpf_dispatch[_vtime]() to scx_bpf_dsq_insert[_vtime]()
In sched_ext API, a repeatedly reported pain point is the overuse of the verb "dispatch" and confusion around "consume": - ops.dispatch() - scx_bpf_dispatch[_vtime]() - scx_bpf_consume() - scx_bpf_dispatch[_vtime]_from_dsq*() This overloading of the term is historical. Originally, there were only built-in DSQs and moving a task into a DSQ always dispatched it for execution. Using the verb "dispatch" for the kfuncs to move tasks into these DSQs made sense. Later, user DSQs were added and scx_bpf_dispatch[_vtime]() updated to be able to insert tasks into any DSQ. The only allowed DSQ to DSQ transfer was from a non-local DSQ to a local DSQ and this operation was named "consume". This was already confusing as a task could be dispatched to a user DSQ from ops.enqueue() and then the DSQ would have to be consumed in ops.dispatch(). Later addition of scx_bpf_dispatch_from_dsq*() made the confusion even worse as "dispatch" in this context meant moving a task to an arbitrary DSQ from a user DSQ. Clean up the API with the following renames: 1. scx_bpf_dispatch[_vtime]() -> scx_bpf_dsq_insert[_vtime]() 2. scx_bpf_consume() -> scx_bpf_dsq_move_to_local() 3. scx_bpf_dispatch[_vtime]_from_dsq*() -> scx_bpf_dsq_move[_vtime]*() This patch performs the first set of renames. Compatibility is maintained by: - The previous kfunc names are still provided by the kernel so that old binaries can run. Kernel generates a warning when the old names are used. - compat.bpf.h provides wrappers for the new names which automatically fall back to the old names when running on older kernels. They also trigger build error if old names are used for new builds. The compat features will be dropped after v6.15. v2: Documentation updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Andrea Righi <arighi@nvidia.com> Acked-by: Changwoo Min <changwoo@igalia.com> Acked-by: Johannes Bechberger <me@mostlynerdless.de> Acked-by: Giovanni Gherdovich <ggherdovich@suse.com> Cc: Dan Schatzberg <dschatzberg@meta.com> Cc: Ming Yang <yougmark94@gmail.com> |
||
|
Tejun Heo
|
a6250aa251 |
sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx()
sched_ext dispatches tasks from the BPF scheduler from balance_scx() and thus every pick_task_scx() call must be preceded by balance_scx(). While this usually holds, due to a bug, there are cases where the fair class's balance() returns true indicating that it has tasks to run on the CPU and thus terminating balance() calls but fails to actually find the next task to run when pick_task() is called. In such cases, pick_task_scx() can be called without preceding balance_scx(). Detect this condition using SCX_RQ_BAL_PENDING flags. If detected, keep running the previous task if possible and avoid stalling from entering idle without balancing. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/Ztj_h5c2LYsdXYbA@slm.duckdns.org |
||
|
Tejun Heo
|
72b85bf6a7 |
sched_ext: scx_bpf_dispatch_from_dsq_set_*() are allowed from unlocked context
|
||
Changwoo Min
|
f39489fea6 |
sched_ext: add a missing rcu_read_lock/unlock pair at scx_select_cpu_dfl()
When getting an LLC CPU mask in the default CPU selection policy, scx_select_cpu_dfl(), a pointer to the sched_domain is dereferenced using rcu_read_lock() without holding rcu_read_lock(). Such an unprotected dereference often causes the following warning and can cause an invalid memory access in the worst case. Therefore, protect dereference of a sched_domain pointer using a pair of rcu_read_lock() and unlock(). [ 20.996135] ============================= [ 20.996345] WARNING: suspicious RCU usage [ 20.996563] 6.11.0-virtme #17 Tainted: G W [ 20.996576] ----------------------------- [ 20.996576] kernel/sched/ext.c:3323 suspicious rcu_dereference_check() usage! [ 20.996576] [ 20.996576] other info that might help us debug this: [ 20.996576] [ 20.996576] [ 20.996576] rcu_scheduler_active = 2, debug_locks = 1 [ 20.996576] 4 locks held by kworker/8:1/140: [ 20.996576] #0: ffff8b18c00dd348 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x4a0/0x590 [ 20.996576] #1: ffffb3da01f67e58 ((work_completion)(&dev->power.work)){+.+.}-{0:0}, at: process_one_work+0x1ba/0x590 [ 20.996576] #2: ffffffffa316f9f0 (&rcu_state.gp_wq){..-.}-{2:2}, at: swake_up_one+0x15/0x60 [ 20.996576] #3: ffff8b1880398a60 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0x59/0x7d0 [ 20.996576] [ 20.996576] stack backtrace: [ 20.996576] CPU: 8 UID: 0 PID: 140 Comm: kworker/8:1 Tainted: G W 6.11.0-virtme #17 [ 20.996576] Tainted: [W]=WARN [ 20.996576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014 [ 20.996576] Workqueue: pm pm_runtime_work [ 20.996576] Sched_ext: simple (disabling+all), task: runnable_at=-6ms [ 20.996576] Call Trace: [ 20.996576] <IRQ> [ 20.996576] dump_stack_lvl+0x6f/0xb0 [ 20.996576] lockdep_rcu_suspicious.cold+0x4e/0x96 [ 20.996576] scx_select_cpu_dfl+0x234/0x260 [ 20.996576] select_task_rq_scx+0xfb/0x190 [ 20.996576] select_task_rq+0x47/0x110 [ 20.996576] try_to_wake_up+0x110/0x7d0 [ 20.996576] swake_up_one+0x39/0x60 [ 20.996576] rcu_core+0xb08/0xe50 [ 20.996576] ? srso_alias_return_thunk+0x5/0xfbef5 [ 20.996576] ? mark_held_locks+0x40/0x70 [ 20.996576] handle_softirqs+0xd3/0x410 [ 20.996576] irq_exit_rcu+0x78/0xa0 [ 20.996576] sysvec_apic_timer_interrupt+0x73/0x80 [ 20.996576] </IRQ> [ 20.996576] <TASK> [ 20.996576] asm_sysvec_apic_timer_interrupt+0x1a/0x20 [ 20.996576] RIP: 0010:_raw_spin_unlock_irqrestore+0x36/0x70 [ 20.996576] Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 11 b4 36 ff 48 89 df e8 99 0d 37 ff f7 c5 00 02 00 00 75 17 9c 58 f6 c4 02 75 2b <65> ff 0d 5b 55 3c 5e 74 16 5b 5d e9 95 8e 28 00 e8 a5 ee 44 ff 9c [ 20.996576] RSP: 0018:ffffb3da01f67d20 EFLAGS: 00000246 [ 20.996576] RAX: 0000000000000002 RBX: ffffffffa4640220 RCX: 0000000000000040 [ 20.996576] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffa1c7b27b [ 20.996576] RBP: 0000000000000246 R08: 0000000000000001 R09: 0000000000000000 [ 20.996576] R10: 0000000000000001 R11: 000000000000021c R12: 0000000000000246 [ 20.996576] R13: ffff8b1881363958 R14: 0000000000000000 R15: ffff8b1881363800 [ 20.996576] ? _raw_spin_unlock_irqrestore+0x4b/0x70 [ 20.996576] serial_port_runtime_resume+0xd4/0x1a0 [ 20.996576] ? __pfx_serial_port_runtime_resume+0x10/0x10 [ 20.996576] __rpm_callback+0x44/0x170 [ 20.996576] ? __pfx_serial_port_runtime_resume+0x10/0x10 [ 20.996576] rpm_callback+0x55/0x60 [ 20.996576] ? __pfx_serial_port_runtime_resume+0x10/0x10 [ 20.996576] rpm_resume+0x582/0x7b0 [ 20.996576] pm_runtime_work+0x7c/0xb0 [ 20.996576] process_one_work+0x1fb/0x590 [ 20.996576] worker_thread+0x18e/0x350 [ 20.996576] ? __pfx_worker_thread+0x10/0x10 [ 20.996576] kthread+0xe2/0x110 [ 20.996576] ? __pfx_kthread+0x10/0x10 [ 20.996576] ret_from_fork+0x34/0x50 [ 20.996576] ? __pfx_kthread+0x10/0x10 [ 20.996576] ret_from_fork_asm+0x1a/0x30 [ 20.996576] </TASK> [ 21.056592] sched_ext: BPF scheduler "simple" disabled (unregistered from user space) Signed-off-by: Changwoo Min <changwoo@igalia.com> Acked-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
|
Changwoo Min
|
153591f703 |
sched_ext: Clarify sched_ext_ops table for userland scheduler
Update the comments in sched_ext_ops to clarify this table is for a BPF scheduler and a userland scheduler should also rely on the sched_ext_ops table through the BPF scheduler. Signed-off-by: Changwoo Min <changwoo@igalia.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
|
Tejun Heo
|
e32c260195 |
sched_ext: Enable the ops breather and eject BPF scheduler on softlockup
On 2 x Intel Sapphire Rapids machines with 224 logical CPUs, a poorly behaving BPF scheduler can live-lock the system by making multiple CPUs bang on the same DSQ to the point where soft-lockup detection triggers before SCX's own watchdog can take action. It also seems possible that the machine can be live-locked enough to prevent scx_ops_helper, which is an RT task, from running in a timely manner. Implement scx_softlockup() which is called when three quarters of soft-lockup threshold has passed. The function immediately enables the ops breather and triggers an ops error to initiate ejection of the BPF scheduler. The previous and this patch combined enable the kernel to reliably recover the system from live-lock conditions that can be triggered by a poorly behaving BPF scheduler on Intel dual socket systems. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Douglas Anderson <dianders@chromium.org> Cc: Andrew Morton <akpm@linux-foundation.org> |
||
|
Tejun Heo
|
62dcbab8b0 |
sched_ext: Avoid live-locking bypass mode switching
A poorly behaving BPF scheduler can live-lock the system by e.g. incessantly banging on the same DSQ on a large NUMA system to the point where switching to the bypass mode can take a long time. Turning on the bypass mode requires dequeueing and re-enqueueing currently runnable tasks, if the DSQs that they are on are live-locked, this can take tens of seconds cascading into other failures. This was observed on 2 x Intel Sapphire Rapids machines with 224 logical CPUs. Inject artifical delays while the bypass mode is switching to guarantee timely completion. While at it, move __scx_ops_bypass_lock into scx_ops_bypass() and rename it to bypass_lock. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Valentin Andrei <vandrei@meta.com> Reported-by: Patrick Lu <patlu@meta.com> |
||
|
Tejun Heo
|
f07b806ad8 |
Merge branch 'for-6.12-fixes' into for-6.13
Pull sched_ext/for-6.12-fixes to receive
|
||
Andrea Righi
|
6d594af5bf |
sched_ext: Fix incorrect use of bitwise AND
There is no reason to use a bitwise AND when checking the conditions to
enable NUMA optimization for the built-in CPU idle selection policy, so
use a logical AND instead.
Fixes:
|
||
|
Andrea Righi
|
f6ce6b9493 |
sched_ext: Do not enable LLC/NUMA optimizations when domains overlap
When the LLC and NUMA domains fully overlap, enabling both optimizations
in the built-in idle CPU selection policy is redundant, as it leads to
searching for an idle CPU within the same domain twice.
Likewise, if all online CPUs are within a single LLC domain, LLC
optimization is unnecessary.
Therefore, detect overlapping domains and enable topology optimizations
only when necessary.
Moreover, rely on the online CPUs for this detection logic, instead of
using the possible CPUs.
Fixes:
|
||
Nam Cao
|
46d076af6d |
sched/idle: Switch to use hrtimer_setup_on_stack()
hrtimer_setup_on_stack() takes the callback function pointer as argument and initializes the timer completely. Replace hrtimer_init_on_stack() and the open coded initialization of hrtimer::function with the new setup mechanism. The conversion was done with Coccinelle. Signed-off-by: Nam Cao <namcao@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/17f9421fed6061df4ad26a4cc91873d2c078cb0f.1730386209.git.namcao@linutronix.de |
||
|
Tejun Heo
|
f7d1b585e1 |
sched_ext: Add a missing newline at the end of an error message
Signed-off-by: Tejun Heo <tj@kernel.org> |
||
Peter Zijlstra
|
35772d627b |
sched: Enable PREEMPT_DYNAMIC for PREEMPT_RT
In order to enable PREEMPT_DYNAMIC for PREEMPT_RT, remove PREEMPT_RT from the 'Preemption Model' choice. Strictly speaking PREEMPT_RT is not a change in how preemption works, but rather it makes a ton more code preemptible. Notably, take away NONE and VOLUNTARY options for PREEMPT_RT, they make no sense (but are techincally possible). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.441622332@infradead.org |
||
|
Peter Zijlstra
|
7c70cb94d2 |
sched: Add Lazy preemption model
Change fair to use resched_curr_lazy(), which, when the lazy preemption model is selected, will set TIF_NEED_RESCHED_LAZY. This LAZY bit will be promoted to the full NEED_RESCHED bit on tick. As such, the average delay between setting LAZY and actually rescheduling will be TICK_NSEC/2. In short, Lazy preemption will delay preemption for fair class but will function as Full preemption for all the other classes, most notably the realtime (RR/FIFO/DEADLINE) classes. The goal is to bridge the performance gap with Voluntary, such that we might eventually remove that option entirely. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.331243614@infradead.org |
||
|
Peter Zijlstra
|
26baa1f1c4 |
sched: Add TIF_NEED_RESCHED_LAZY infrastructure
Add the basic infrastructure to split the TIF_NEED_RESCHED bit in two. Either bit will cause a resched on return-to-user, but only TIF_NEED_RESCHED will drive IRQ preemption. No behavioural change intended. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20241007075055.219540785@infradead.org |
||
Thomas Gleixner
|
0f0d1b8e50 |
sched/ext: Remove sched_fork() hack
Instead of solving the underlying problem of the double invocation of
__sched_fork() for idle tasks, sched-ext decided to hack around the issue
by partially clearing out the entity struct to preserve the already
enqueued node. A provided analysis and solution has been ignored for four
months.
Now that someone else has taken care of cleaning it up, remove the
disgusting hack and clear out the full structure. Remove the comment in the
structure declaration as well, as there is no requirement for @node being
the last element anymore.
Fixes:
|
||
|
Thomas Gleixner
|
b23decf8ac |
sched: Initialize idle tasks only once
Idle tasks are initialized via __sched_fork() twice:
fork_idle()
copy_process()
sched_fork()
__sched_fork()
init_idle()
__sched_fork()
Instead of cleaning this up, sched_ext hacked around it. Even when analyis
and solution were provided in a discussion, nobody cared to clean this up.
init_idle() is also invoked from sched_init() to initialize the boot CPU's
idle task, which requires the __sched_fork() invocation. But this can be
trivially solved by invoking __sched_fork() before init_idle() in
sched_init() and removing the __sched_fork() invocation from init_idle().
Do so and clean up the comments explaining this historical leftover.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241028103142.359584747@linutronix.de
|
||
|
Linus Torvalds
|
33e83ffe4c |
A few scheduler fixes:
- Plug a race between pick_next_task_fair() and try_to_wake_up() where
both try to write to the same task, even though both paths hold a
runqueue lock, but obviously from different runqueues.
The problem is that the store to task::on_rq in __block_task() is
visible to try_to_wake_up() which assumes that the task is not queued.
Both sides then operate on the same task.
Cure it by rearranging __block_task() so the the store to task::on_rq is
the last operation on the task.
- Prevent a potential NULL pointer dereference in task_numa_work()
task_numa_work() iterates the VMAs of a process. A concurrent unmap of
the address space can result in a NULL pointer return from vma_next()
which is unchecked.
Add the missing NULL pointer check to prevent this.
- Operate on the correct scheduler policy in task_should_scx()
task_should_scx() returns true when a task should be handled by sched
EXT. It checks the tasks scheduling policy.
This fails when the check is done before a policy has been set.
Cure it by handing the policy into task_should_scx() so it operates
on the requested value.
- Add the missing handling of sched EXT in the delayed dequeue
mechanism. This was simply forgotten.
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Merge tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Thomas Gleixner:
- Plug a race between pick_next_task_fair() and try_to_wake_up() where
both try to write to the same task, even though both paths hold a
runqueue lock, but obviously from different runqueues.
The problem is that the store to task::on_rq in __block_task() is
visible to try_to_wake_up() which assumes that the task is not
queued. Both sides then operate on the same task.
Cure it by rearranging __block_task() so the the store to task::on_rq
is the last operation on the task.
- Prevent a potential NULL pointer dereference in task_numa_work()
task_numa_work() iterates the VMAs of a process. A concurrent unmap
of the address space can result in a NULL pointer return from
vma_next() which is unchecked.
Add the missing NULL pointer check to prevent this.
- Operate on the correct scheduler policy in task_should_scx()
task_should_scx() returns true when a task should be handled by sched
EXT. It checks the tasks scheduling policy.
This fails when the check is done before a policy has been set.
Cure it by handing the policy into task_should_scx() so it operates
on the requested value.
- Add the missing handling of sched EXT in the delayed dequeue
mechanism. This was simply forgotten.
* tag 'sched-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/ext: Fix scx vs sched_delayed
sched: Pass correct scheduling policy to __setscheduler_class
sched/numa: Fix the potential null pointer dereference in task_numa_work()
sched: Fix pick_next_task_fair() vs try_to_wake_up() race
|
||
|
Peter Zijlstra
|
69d5e722be |
sched/ext: Fix scx vs sched_delayed
Commit |
||
|
Linus Torvalds
|
daa9f66fe1 |
sched_ext: Fixes for v6.12-rc5
- Instances of scx_ops_bypass() could race each other leading to misbehavior. Fix by protecting the operation with a spinlock. - selftest and userspace header fixes. -----BEGIN PGP SIGNATURE----- iIQEABYKACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCZyF/5Q4cdGpAa2VybmVs Lm9yZwAKCRCxYfJx3gVYGRi+AP4+jGUz+O1LS0bCNj44Xlr0v6kci5dfJR7TlBv5 hwROcgEA84i7nRq6oJ1IkK7ItLbZYwgZyxqdn0Pgsq+oMWhgAwE= =R766 -----END PGP SIGNATURE----- Merge tag 'sched_ext-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: - Instances of scx_ops_bypass() could race each other leading to misbehavior. Fix by protecting the operation with a spinlock. - selftest and userspace header fixes * tag 'sched_ext-for-6.12-rc5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Fix enq_last_no_enq_fails selftest sched_ext: Make cast_mask() inline scx: Fix raciness in scx_ops_bypass() scx: Fix exit selftest to use custom DSQ sched_ext: Fix function pointer type mismatches in BPF selftests selftests/sched_ext: add order-only dependency of runner.o on BPFOBJ |
||
|
Andrea Righi
|
860a45219b |
sched_ext: Introduce NUMA awareness to the default idle selection policy
Similarly to commit
|
||
Aboorva Devarajan
|
5db91545ef |
sched: Pass correct scheduling policy to __setscheduler_class
Commit |
||
Johannes Weiner
|
1a6151017e |
sched: psi: pass enqueue/dequeue flags to psi callbacks directly
What psi needs to do on each enqueue and dequeue has gotten more subtle, and the generic sched code trying to distill this into a bool for the callbacks is awkward. Pass the flags directly and let psi parse them. For that to work, the #include "stats.h" (which has the psi callback implementations) needs to be below the flag definitions in "sched.h". Move that section further down, next to some of the other accounting stuff. This also puts the ENQUEUE_SAVE/RESTORE branch behind the psi jump label, slightly reducing overhead when PSI=y but runtime disabled. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20241014144358.GB1021@cmpxchg.org |
||
Shawn Wang
|
9c70b2a33c |
sched/numa: Fix the potential null pointer dereference in task_numa_work()
When running stress-ng-vm-segv test, we found a null pointer dereference
error in task_numa_work(). Here is the backtrace:
[323676.066985] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
......
[323676.067108] CPU: 35 PID: 2694524 Comm: stress-ng-vm-se
......
[323676.067113] pstate: 23401009 (nzCv daif +PAN -UAO +TCO +DIT +SSBS BTYPE=--)
[323676.067115] pc : vma_migratable+0x1c/0xd0
[323676.067122] lr : task_numa_work+0x1ec/0x4e0
[323676.067127] sp : ffff8000ada73d20
[323676.067128] x29: ffff8000ada73d20 x28: 0000000000000000 x27: 000000003e89f010
[323676.067130] x26: 0000000000080000 x25: ffff800081b5c0d8 x24: ffff800081b27000
[323676.067133] x23: 0000000000010000 x22: 0000000104d18cc0 x21: ffff0009f7158000
[323676.067135] x20: 0000000000000000 x19: 0000000000000000 x18: ffff8000ada73db8
[323676.067138] x17: 0001400000000000 x16: ffff800080df40b0 x15: 0000000000000035
[323676.067140] x14: ffff8000ada73cc8 x13: 1fffe0017cc72001 x12: ffff8000ada73cc8
[323676.067142] x11: ffff80008001160c x10: ffff000be639000c x9 : ffff8000800f4ba4
[323676.067145] x8 : ffff000810375000 x7 : ffff8000ada73974 x6 : 0000000000000001
[323676.067147] x5 : 0068000b33e26707 x4 : 0000000000000001 x3 : ffff0009f7158000
[323676.067149] x2 : 0000000000000041 x1 : 0000000000004400 x0 : 0000000000000000
[323676.067152] Call trace:
[323676.067153] vma_migratable+0x1c/0xd0
[323676.067155] task_numa_work+0x1ec/0x4e0
[323676.067157] task_work_run+0x78/0xd8
[323676.067161] do_notify_resume+0x1ec/0x290
[323676.067163] el0_svc+0x150/0x160
[323676.067167] el0t_64_sync_handler+0xf8/0x128
[323676.067170] el0t_64_sync+0x17c/0x180
[323676.067173] Code: d2888001 910003fd f9000bf3 aa0003f3 (f9401000)
[323676.067177] SMP: stopping secondary CPUs
[323676.070184] Starting crashdump kernel...
stress-ng-vm-segv in stress-ng is used to stress test the SIGSEGV error
handling function of the system, which tries to cause a SIGSEGV error on
return from unmapping the whole address space of the child process.
Normally this program will not cause kernel crashes. But before the
munmap system call returns to user mode, a potential task_numa_work()
for numa balancing could be added and executed. In this scenario, since the
child process has no vma after munmap, the vma_next() in task_numa_work()
will return a null pointer even if the vma iterator restarts from 0.
Recheck the vma pointer before dereferencing it in task_numa_work().
Fixes:
|
||
|
Christian Loehle
|
23f1178ad7 |
sched/uclamp: Fix unnused variable warning
uclamp_mutex is only used for CONFIG_SYSCTL or CONFIG_UCLAMP_TASK_GROUP so declare it __maybe_unused. Closes: https://lore.kernel.org/oe-kbuild-all/202410060258.bPl2ZoUo-lkp@intel.com/ Closes: https://lore.kernel.org/oe-kbuild-all/202410250459.EJe6PJI5-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/a1e9c342-01c9-44f0-a789-2c908e57942b@arm.com |
||
David Vernet
|
0e7ffff1b8 |
scx: Fix raciness in scx_ops_bypass()
scx_ops_bypass() can currently race on the ops enable / disable path as
follows:
1. scx_ops_bypass(true) called on enable path, bypass depth is set to 1
2. An op on the init path exits, which schedules scx_ops_disable_workfn()
3. scx_ops_bypass(false) is called on the disable path, and bypass depth
is decremented to 0
4. kthread is scheduled to execute scx_ops_disable_workfn()
5. scx_ops_bypass(true) called, bypass depth set to 1
6. scx_ops_bypass() races when iterating over CPUs
While it's not safe to take any blocking locks on the bypass path, it is
safe to take a raw spinlock which cannot be preempted. This patch therefore
updates scx_ops_bypass() to use a raw spinlock to synchronize, and changes
scx_ops_bypass_depth to be a regular int.
Without this change, we observe the following warnings when running the
'exit' sched_ext selftest (sometimes requires a couple of runs):
.[root@virtme-ng sched_ext]# ./runner -t exit
===== START =====
TEST: exit
...
[ 14.935078] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4332 scx_ops_bypass+0x1ca/0x280
[ 14.935126] Modules linked in:
[ 14.935150] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Not tainted 6.11.0-virtme #24
[ 14.935192] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 14.935242] Sched_ext: exit (enabling+all)
[ 14.935244] RIP: 0010:scx_ops_bypass+0x1ca/0x280
[ 14.935300] Code: ff ff ff e8 48 96 10 00 fb e9 08 ff ff ff c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 0f 0b 90 41 8b 84 24 24
[ 14.935394] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010002
[ 14.935424] RAX: 0000000000000009 RBX: 0000000000000001 RCX: 00000000e3fb8b2a
[ 14.935465] RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff88a4c080
[ 14.935512] RBP: 0000000000009b56 R08: 0000000000000004 R09: 00000003f12e520a
[ 14.935555] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300
[ 14.935598] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018
[ 14.935642] FS: 0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000
[ 14.935684] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 14.935721] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0
[ 14.935765] PKRU: 55555554
[ 14.935782] Call Trace:
[ 14.935802] <TASK>
[ 14.935823] ? __warn+0xce/0x220
[ 14.935850] ? scx_ops_bypass+0x1ca/0x280
[ 14.935881] ? report_bug+0xc1/0x160
[ 14.935909] ? handle_bug+0x61/0x90
[ 14.935934] ? exc_invalid_op+0x1a/0x50
[ 14.935959] ? asm_exc_invalid_op+0x1a/0x20
[ 14.935984] ? raw_spin_rq_lock_nested+0x15/0x30
[ 14.936019] ? scx_ops_bypass+0x1ca/0x280
[ 14.936046] ? srso_alias_return_thunk+0x5/0xfbef5
[ 14.936081] ? __pfx_scx_ops_disable_workfn+0x10/0x10
[ 14.936111] scx_ops_disable_workfn+0x146/0xac0
[ 14.936142] ? finish_task_switch+0xa9/0x2c0
[ 14.936172] ? srso_alias_return_thunk+0x5/0xfbef5
[ 14.936211] ? __pfx_scx_ops_disable_workfn+0x10/0x10
[ 14.936244] kthread_worker_fn+0x101/0x2c0
[ 14.936268] ? __pfx_kthread_worker_fn+0x10/0x10
[ 14.936299] kthread+0xec/0x110
[ 14.936327] ? __pfx_kthread+0x10/0x10
[ 14.936351] ret_from_fork+0x37/0x50
[ 14.936374] ? __pfx_kthread+0x10/0x10
[ 14.936400] ret_from_fork_asm+0x1a/0x30
[ 14.936427] </TASK>
[ 14.936443] irq event stamp: 21002
[ 14.936467] hardirqs last enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0
[ 14.936521] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280
[ 14.936571] softirqs last enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[ 14.936622] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[ 14.936672] ---[ end trace 0000000000000000 ]---
[ 14.953282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 14.953352] ------------[ cut here ]------------
[ 14.953383] WARNING: CPU: 2 PID: 360 at kernel/sched/ext.c:4335 scx_ops_bypass+0x1d8/0x280
[ 14.953428] Modules linked in:
[ 14.953453] CPU: 2 UID: 0 PID: 360 Comm: sched_ext_ops_h Tainted: G W 6.11.0-virtme #24
[ 14.953505] Tainted: [W]=WARN
[ 14.953527] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 14.953574] RIP: 0010:scx_ops_bypass+0x1d8/0x280
[ 14.953603] Code: c6 05 7b 34 e8 01 01 90 48 c7 c7 89 86 88 87 e8 be 1d f8 ff 90 0f 0b 90 90 eb 95 90 0f 0b 90 41 8b 84 24 24 0a 00 00 eb 97 90 <0f> 0b 90 41 8b 84 24 24 0a 00 00 eb 92 f3 0f 1e fa 49 8d 84 24 f0
[ 14.953693] RSP: 0018:ffffb706c0957ce0 EFLAGS: 00010046
[ 14.953722] RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001
[ 14.953763] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8fc5fec31318
[ 14.953804] RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
[ 14.953845] R10: ffffffff863a9795 R11: 0000000000000000 R12: ffff8fc5fec31300
[ 14.953888] R13: ffff8fc5fec31318 R14: 0000000000000286 R15: 0000000000000018
[ 14.953934] FS: 0000000000000000(0000) GS:ffff8fc5fe680000(0000) knlGS:0000000000000000
[ 14.953974] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 14.954009] CR2: 0000557d92890b88 CR3: 000000002464a000 CR4: 0000000000750ef0
[ 14.954052] PKRU: 55555554
[ 14.954068] Call Trace:
[ 14.954085] <TASK>
[ 14.954102] ? __warn+0xce/0x220
[ 14.954126] ? scx_ops_bypass+0x1d8/0x280
[ 14.954150] ? report_bug+0xc1/0x160
[ 14.954178] ? handle_bug+0x61/0x90
[ 14.954203] ? exc_invalid_op+0x1a/0x50
[ 14.954226] ? asm_exc_invalid_op+0x1a/0x20
[ 14.954250] ? raw_spin_rq_lock_nested+0x15/0x30
[ 14.954285] ? scx_ops_bypass+0x1d8/0x280
[ 14.954311] ? __mutex_unlock_slowpath+0x3a/0x260
[ 14.954343] scx_ops_disable_workfn+0xa3e/0xac0
[ 14.954381] ? __pfx_scx_ops_disable_workfn+0x10/0x10
[ 14.954413] kthread_worker_fn+0x101/0x2c0
[ 14.954442] ? __pfx_kthread_worker_fn+0x10/0x10
[ 14.954479] kthread+0xec/0x110
[ 14.954507] ? __pfx_kthread+0x10/0x10
[ 14.954530] ret_from_fork+0x37/0x50
[ 14.954553] ? __pfx_kthread+0x10/0x10
[ 14.954576] ret_from_fork_asm+0x1a/0x30
[ 14.954603] </TASK>
[ 14.954621] irq event stamp: 21002
[ 14.954644] hardirqs last enabled at (21001): [<ffffffff863aa35f>] resched_cpu+0x9f/0xd0
[ 14.954686] hardirqs last disabled at (21002): [<ffffffff863dd0ba>] scx_ops_bypass+0x11a/0x280
[ 14.954735] softirqs last enabled at (20642): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[ 14.954782] softirqs last disabled at (20637): [<ffffffff863683d7>] __irq_exit_rcu+0x67/0xd0
[ 14.954829] ---[ end trace 0000000000000000 ]---
[ 15.022283] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 15.092282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 15.149282] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
ok 1 exit #
===== END =====
And with it, the test passes without issue after 1000s of runs:
.[root@virtme-ng sched_ext]# ./runner -t exit
===== START =====
TEST: exit
DESCRIPTION: Verify we can cleanly exit a scheduler in multiple places
OUTPUT:
[ 7.412856] sched_ext: BPF scheduler "exit" enabled
[ 7.427924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 7.466677] sched_ext: BPF scheduler "exit" enabled
[ 7.475923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 7.512803] sched_ext: BPF scheduler "exit" enabled
[ 7.532924] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 7.586809] sched_ext: BPF scheduler "exit" enabled
[ 7.595926] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 7.661923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
[ 7.723923] sched_ext: BPF scheduler "exit" disabled (unregistered from BPF)
ok 1 exit #
===== END =====
=============================
RESULTS:
PASSED: 1
SKIPPED: 0
FAILED: 0
Fixes:
|
||
|
Tejun Heo
|
b7d0bbcf0c |
sched_ext: Replace set_arg_maybe_null() with __nullable CFI stub tags
ops.dispatch() and ops.yield() may be fed a NULL task_struct pointer. set_arg_maybe_null() is used to tell the verifier that they should be NULL checked before being dereferenced. BPF now has an a lot prettier way to express this - tagging arguments in CFI stubs with __nullable. Replace set_arg_maybe_null() with __nullable CFI stub tags. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> |
||
|
Tejun Heo
|
cf583264d0 |
sched_ext: Rename CFI stubs to names that are recognized by BPF
CFI stubs can be used to tag arguments with __nullable (and possibly other tags in the future) but for that to work the CFI stubs must have names that are recognized by BPF. Rename them. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David Vernet <void@manifault.com> Acked-by: Martin KaFai Lau <martin.lau@kernel.org> Acked-by: Alexei Starovoitov <ast@kernel.org> |
||
|
Andrea Righi
|
dfa4ed29b1 |
sched_ext: Introduce LLC awareness to the default idle selection policy
Rely on the scheduler topology information to implement basic LLC awareness in the sched_ext build-in idle selection policy. This allows schedulers using the built-in policy to make more informed decisions when selecting an idle CPU in systems with multiple LLCs, such as NUMA systems or chiplet-based architectures, and it helps keep tasks within the same LLC domain, thereby improving cache locality. For efficiency, LLC awareness is applied only to tasks that can run on all the CPUs in the system for now. If a task's affinity is modified from user space, it's the responsibility of user space to choose the appropriate optimized scheduling domain. Signed-off-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
|
Andrea Righi
|
b452ae4d20 |
sched_ext: Clarify ops.select_cpu() for single-CPU tasks
Update ops.select_cpu() documentation to clarify that this method is not called for tasks that are restricted to run on a single CPU, as these tasks do not have the option to select a different CPU. Signed-off-by: Andrea Righi <arighi@nvidia.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
|
Peter Zijlstra
|
b55945c500 |
sched: Fix pick_next_task_fair() vs try_to_wake_up() race
Syzkaller robot reported KCSAN tripping over the
ASSERT_EXCLUSIVE_WRITER(p->on_rq) in __block_task().
The report noted that both pick_next_task_fair() and try_to_wake_up()
were concurrently trying to write to the same p->on_rq, violating the
assertion -- even though both paths hold rq->__lock.
The logical consequence is that both code paths end up holding a
different rq->__lock. And looking through ttwu(), this is possible
when the __block_task() 'p->on_rq = 0' store is visible to the ttwu()
'p->on_rq' load, which then assumes the task is not queued and
continues to migrate it.
Rearrange things such that __block_task() releases @p with the store
and no code thereafter will use @p again.
Fixes:
|
||
Aleksa Sarai
|
112cca098a
|
sched_getattr: port to copy_struct_to_user
sched_getattr(2) doesn't care about trailing non-zero bytes in the (ksize > usize) case, so just use copy_struct_to_user() without checking ignored_trailing. Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Link: https://lore.kernel.org/r/20241010-extensible-structs-check_fields-v3-2-d2833dfe6edd@cyphar.com Signed-off-by: Christian Brauner <brauner@kernel.org> |
||
Ingo Molnar
|
d1fb8a78b2 |
Linux 6.12-rc4
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmcVgfoeHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGhCYH/0Sdfp3cIq3JWLRv HCkWhPkPbEvR5XQlYQsAvTPVrEc0ZG9PKlXCaYaa8Tvt8xQ7WT/VDTjKgaWEhr8s qa6bNTx1zggiNBTP/3jYsNliOyAYfw5qjxA7fpEmueAeuT5y1XKZFKPHEXE/1qbR 8zeISKTkE0qwUmLqCdXe2qBWFnCC5i+78RcI6IN7uErnuNWk7ssapldgU4DB+dEl DDRxi1FTvARGPQGl8T+jPkfJiugv87ksG7l4WsqcYgoW+045K76C7I6vQjkDOrsd wqtPIow/yPmGQbbdRhWLxNU+wDmselYQ6xp7aMxppNF45HoHtzNm+X+T2ZU3bPoP iT2Mkbg= =+GXK -----END PGP SIGNATURE----- Merge tag 'v6.12-rc4' into sched/core, to resolve conflict Overlapping fixes solving the same bug slightly differently: |
||
Andrea Righi
|
21b8964826 |
sched_ext: improve WAKE_SYNC behavior for default idle CPU selection
In the sched_ext built-in idle CPU selection logic, when handling a WF_SYNC wakeup, we always attempt to migrate the task to the waker's CPU, as the waker is expected to yield the CPU after waking the task. However, it may be preferable to keep the task on its previous CPU if the waker's CPU is cache-affine. The same approach is also used by the fair class and in other scx schedulers, like scx_rusty and scx_bpfland. Therefore, apply the same logic to the built-in idle CPU selection policy as well. Signed-off-by: Andrea Righi <andrea.righi@linux.dev> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
Tianchen Ding
|
ba1c9d327e |
sched_ext: Use btf_ids to resolve task_struct
Save the searching time during bpf_scx_init. Signed-off-by: Tianchen Ding <dtcccc@linux.alibaba.com> Signed-off-by: Tejun Heo <tj@kernel.org> |
||
|
Ingo Molnar
|
be602cde65 |
Merge branch 'linus' into sched/urgent, to resolve conflict
Conflicts: kernel/sched/ext.c There's a context conflict between this upstream commit: |
||
|
Linus Torvalds
|
dff6584301 |
sched_ext: Fixes for v6.12-rc3
- More issues reported in the enable/disable paths on large machines with many tasks due to scx_tasks_lock being held too long. Break up the task iterations. - Remove ops.select_cpu() dependency in bypass mode so that a misbehaving implementation can't live-lock the machine by pushing all tasks to few CPUs in bypass mode. - Other misc fixes. -----BEGIN PGP SIGNATURE----- iIQEABYKACwWIQTfIjM1kS57o3GsC/uxYfJx3gVYGQUCZw7SMw4cdGpAa2VybmVs Lm9yZwAKCRCxYfJx3gVYGU6+AQDZKNsyRw0c8+rd7eASAtCzvzBU1KGf3RPrsbNF pb3IGgEA4/uVBlVny10ZyeKaQ4A3L2G4ROyJwNEygUvhkvbfcgk= =z7d9 -----END PGP SIGNATURE----- Merge tag 'sched_ext-for-6.12-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext Pull sched_ext fixes from Tejun Heo: - More issues reported in the enable/disable paths on large machines with many tasks due to scx_tasks_lock being held too long. Break up the task iterations - Remove ops.select_cpu() dependency in bypass mode so that a misbehaving implementation can't live-lock the machine by pushing all tasks to few CPUs in bypass mode - Other misc fixes * tag 'sched_ext-for-6.12-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: sched_ext: Remove unnecessary cpu_relax() sched_ext: Don't hold scx_tasks_lock for too long sched_ext: Move scx_tasks_lock handling into scx_task_iter helpers sched_ext: bypass mode shouldn't depend on ops.select_cpu() sched_ext: Move scx_buildin_idle_enabled check to scx_bpf_select_cpu_dfl() sched_ext: Start schedulers with consistent p->scx.slice values Revert "sched_ext: Use shorter slice while bypassing" sched_ext: use correct function name in pick_task_scx() warning message selftests: sched_ext: Add sched_ext as proper selftest target |
||
|
David Vernet
|
60e339be10 |
sched_ext: Remove unnecessary cpu_relax()
As described in commit
|