Commit Graph

46994 Commits

Author SHA1 Message Date
Andrea Righi
e4855fc90e sched_ext: idle: Refactor scx_select_cpu_dfl()
Make scx_select_cpu_dfl() more consistent with the other idle-related
APIs by returning a negative value when an idle CPU isn't found.

No functional changes, this is purely a refactoring.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-14 08:17:11 -10:00
Andrea Righi
c414c2171c sched_ext: idle: Honor idle flags in the built-in idle selection policy
Enable passing idle flags (%SCX_PICK_IDLE_*) to scx_select_cpu_dfl(),
to enforce strict selection criteria, such as selecting an idle CPU
strictly within @prev_cpu's node or choosing only a fully idle SMT core.

This functionality will be exposed through a dedicated kfunc in a
separate patch.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-14 08:17:01 -10:00
Andrea Righi
97e13ecb02 sched_ext: Skip per-CPU tasks in scx_bpf_reenqueue_local()
scx_bpf_reenqueue_local() can be invoked from ops.cpu_release() to give
tasks that are queued to the local DSQ a chance to migrate to other
CPUs, when a CPU is taken by a higher scheduling class.

However, there is no point re-enqueuing tasks that can only run on that
particular CPU, as they would simply be re-added to the same local DSQ
without any benefit.

Therefore, skip per-CPU tasks in scx_bpf_reenqueue_local().

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-13 07:07:27 -10:00
Changwoo Min
71d078803c sched_ext: Add trace point to track sched_ext core events
Add tracing support to track sched_ext core events
(/sched_ext/sched_ext_event). This may be useful for debugging sched_ext
schedulers that trigger a particular event.

The trace point can be used as other trace points, so it can be used in,
for example, `perf trace` and BPF programs, as follows:

======
$> sudo perf trace -e sched_ext:sched_ext_event --filter 'name == "SCX_EV_ENQ_SLICE_DFL"'
======

======
struct tp_sched_ext_event {
	struct trace_entry ent;
	u32 __data_loc_name;
	s64 delta;
};

SEC("tracepoint/sched_ext/sched_ext_event")
int rtp_add_event(struct tp_sched_ext_event *ctx)
{
	char event_name[128];
	unsigned short offset = ctx->__data_loc_name & 0xFFFF;
        bpf_probe_read_str((void *)event_name, 128, (char *)ctx + offset);

	bpf_printk("name %s   delta %lld", event_name, ctx->delta);
	return 0;
}
======

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-04 08:06:17 -10:00
Changwoo Min
038730dc12 sched_ext: Change the event type from u64 to s64
The event count could be negative in the future,
so change the event type from u64 to s64.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-04 08:05:23 -10:00
Tejun Heo
8a9b1585e2 sched_ext: Merge branch 'for-6.14-fixes' into for-6.15
Pull for-6.14-fixes to receive:

  9360dfe4cb ("sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()")

which conflicts with:

  337d1b354a ("sched_ext: Move built-in idle CPU selection policy to a separate file")

Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-03 08:02:22 -10:00
Andrea Righi
9360dfe4cb sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()
If a BPF scheduler provides an invalid CPU (outside the nr_cpu_ids
range) as prev_cpu to scx_bpf_select_cpu_dfl() it can cause a kernel
crash.

To prevent this, validate prev_cpu in scx_bpf_select_cpu_dfl() and
trigger an scx error if an invalid CPU is specified.

Fixes: f0e1a0643a ("sched_ext: Implement BPF extensible scheduler class")
Cc: stable@vger.kernel.org # v6.12+
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-03-03 07:55:48 -10:00
Andrea Righi
fde7d64766 sched_ext: idle: Fix scx_bpf_pick_any_cpu_node() behavior
When %SCX_PICK_IDLE_IN_NODE is specified, scx_bpf_pick_any_cpu_node()
should always return a CPU from the specified node, regardless of its
idle state.

Also clarify this logic in the function documentation.

Fixes: 01059219b0 ("sched_ext: idle: Introduce node-aware idle cpu kfunc helpers")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-25 08:35:53 -10:00
Tejun Heo
8fef0a3b17 sched_ext: Fix pick_task_scx() picking non-queued tasks when it's called without balance()
a6250aa251 ("sched_ext: Handle cases where pick_task_scx() is called
without preceding balance_scx()") added a workaround to handle the cases
where pick_task_scx() is called without prececing balance_scx() which is due
to a fair class bug where pick_taks_fair() may return NULL after a true
return from balance_fair().

The workaround detects when pick_task_scx() is called without preceding
balance_scx() and emulates SCX_RQ_BAL_KEEP and triggers kicking to avoid
stalling. Unfortunately, the workaround code was testing whether @prev was
on SCX to decide whether to keep the task running. This is incorrect as the
task may be on SCX but no longer runnable.

This could lead to a non-runnable task to be returned from pick_task_scx()
which cause interesting confusions and failures. e.g. A common failure mode
is the task ending up with (!on_rq && on_cpu) state which can cause
potential wakers to busy loop, which can easily lead to deadlocks.

Fix it by testing whether @prev has SCX_TASK_QUEUED set. This makes
@prev_on_scx only used in one place. Open code the usage and improve the
comment while at it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Pat Cody <patcody@meta.com>
Fixes: a6250aa251 ("sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx()")
Cc: stable@vger.kernel.org # v6.12+
Acked-by: Andrea Righi <arighi@nvidia.com>
2025-02-25 08:28:52 -10:00
Andrea Righi
0e9b4c10e8 sched_ext: idle: Introduce scx_bpf_nr_node_ids()
Similarly to scx_bpf_nr_cpu_ids(), introduce a new kfunc
scx_bpf_nr_node_ids() to expose the maximum number of NUMA nodes in the
system.

BPF schedulers can use this information together with the new node-aware
kfuncs, for example to create per-node DSQs, validate node IDs, etc.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-24 07:37:42 -10:00
Andrea Righi
01059219b0 sched_ext: idle: Introduce node-aware idle cpu kfunc helpers
Introduce a new kfunc to retrieve the node associated to a CPU:

 int scx_bpf_cpu_node(s32 cpu)

Add the following kfuncs to provide BPF schedulers direct access to
per-node idle cpumasks information:

 const struct cpumask *scx_bpf_get_idle_cpumask_node(int node)
 const struct cpumask *scx_bpf_get_idle_smtmask_node(int node)
 s32 scx_bpf_pick_idle_cpu_node(const cpumask_t *cpus_allowed,
 				int node, u64 flags)
 s32 scx_bpf_pick_any_cpu_node(const cpumask_t *cpus_allowed,
 			       int node, u64 flags)

Moreover, trigger an scx error when any of the non-node aware idle CPU
kfuncs are used when SCX_OPS_BUILTIN_IDLE_PER_NODE is enabled.

Cc: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-18 09:10:24 -10:00
Andrea Righi
48849271e6 sched_ext: idle: Per-node idle cpumasks
Using a single global idle mask can lead to inefficiencies and a lot of
stress on the cache coherency protocol on large systems with multiple
NUMA nodes, since all the CPUs can create a really intense read/write
activity on the single global cpumask.

Therefore, split the global cpumask into multiple per-NUMA node cpumasks
to improve scalability and performance on large systems.

The concept is that each cpumask will track only the idle CPUs within
its corresponding NUMA node, treating CPUs in other NUMA nodes as busy.
In this way concurrent access to the idle cpumask will be restricted
within each NUMA node.

The split of multiple per-node idle cpumasks can be controlled using the
SCX_OPS_BUILTIN_IDLE_PER_NODE flag.

By default SCX_OPS_BUILTIN_IDLE_PER_NODE is not enabled and a global
host-wide idle cpumask is used, maintaining the previous behavior.

NOTE: if a scheduler explicitly enables the per-node idle cpumasks (via
SCX_OPS_BUILTIN_IDLE_PER_NODE), scx_bpf_get_idle_cpu/smtmask() will
trigger an scx error, since there are no system-wide cpumasks.

= Test =

Hardware:
 - System: DGX B200
    - CPUs: 224 SMT threads (112 physical cores)
    - Processor: INTEL(R) XEON(R) PLATINUM 8570
    - 2 NUMA nodes

Scheduler:
 - scx_simple [1] (so that we can focus at the built-in idle selection
   policy and not at the scheduling policy itself)

Test:
 - Run a parallel kernel build `make -j $(nproc)` and measure the average
   elapsed time over 10 runs:

          avg time | stdev
          ---------+------
 before:   52.431s | 2.895
  after:   50.342s | 2.895

= Conclusion =

Splitting the global cpumask into multiple per-NUMA cpumasks helped to
achieve a speedup of approximately +4% with this particular architecture
and test case.

The same test on a DGX-1 (40 physical cores, Intel Xeon E5-2698 v4 @
2.20GHz, 2 NUMA nodes) shows a speedup of around 1.5-3%.

On smaller systems, I haven't noticed any measurable regressions or
improvements with the same test (parallel kernel build) and scheduler
(scx_simple).

Moreover, with a modified scx_bpfland that uses the new NUMA-aware APIs
I observed an additional +2-2.5% performance improvement with the same
test.

[1] https://github.com/sched-ext/scx/blob/main/scheds/c/scx_simple.bpf.c

Cc: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-16 06:52:20 -10:00
Andrea Righi
0aaaf89df8 sched_ext: idle: Introduce SCX_OPS_BUILTIN_IDLE_PER_NODE
Add the new scheduler flag SCX_OPS_BUILTIN_IDLE_PER_NODE, which allows
BPF schedulers to select between using a global flat idle cpumask or
multiple per-node cpumasks.

This only introduces the flag and the mechanism to enable/disable this
feature without affecting any scheduling behavior.

Cc: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-16 06:52:20 -10:00
Andrea Righi
d73249f887 sched_ext: idle: Make idle static keys private
Make all the static keys used by the idle CPU selection policy private
to ext_idle.c. This avoids unnecessary exposure in headers and improves
code encapsulation.

Cc: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-16 06:52:20 -10:00
Changwoo Min
ad3b301aa0 sched_ext: Provides a sysfs 'events' to expose core event counters
Add a sysfs entry at /sys/kernel/sched_ext/root/events to expose core
event counters through the files system interface. Each line of the file
shows the event name and its counter value.

In addition, the format of scx_dump_event() is adjusted as the event name
gets longer.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-14 07:15:41 -10:00
Tejun Heo
3539c6411a sched_ext: Implement SCX_OPS_ALLOW_QUEUED_WAKEUP
A task wakeup can be either processed on the waker's CPU or bounced to the
wakee's previous CPU using an IPI (ttwu_queue). Bouncing to the wakee's CPU
avoids the waker's CPU locking and accessing the wakee's rq which can be
expensive across cache and node boundaries.

When ttwu_queue path is taken, select_task_rq() and thus ops.select_cpu()
may be skipped in some cases (racing against the wakee switching out). As
this confused some BPF schedulers, there wasn't a good way for a BPF
scheduler to tell whether idle CPU selection has been skipped, ops.enqueue()
couldn't insert tasks into foreign local DSQs, and the performance
difference on machines with simple toplogies were minimal, sched_ext
disabled ttwu_queue.

However, this optimization makes noticeable difference on more complex
topologies and a BPF scheduler now has an easy way tell whether
ops.select_cpu() was skipped since 9b671793c7 ("sched_ext, scx_qmap: Add
and use SCX_ENQ_CPU_SELECTED") and can insert tasks into foreign local DSQs
since 5b26f7b920 ("sched_ext: Allow SCX_DSQ_LOCAL_ON for direct
dispatches").

Implement SCX_OPS_ALLOW_QUEUED_WAKEUP which allows BPF schedulers to choose
to enable ttwu_queue optimization.

v2: Update the patch description and comment re. ops.select_cpu() being
    skipped in some cases as opposed to always as per Neel.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Neel Natu <neelnatu@google.com>
Reported-by: Barret Rhoden <brho@google.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
2025-02-13 07:30:46 -10:00
Chuyi Zhou
f5717c93a1 sched_ext: Use SCX_CALL_OP_TASK in task_tick_scx
Now when we use scx_bpf_task_cgroup() in ops.tick() to get the cgroup of
the current task, the following error will occur:

scx_foo[3795244] triggered exit kind 1024:
  runtime error (called on a task not being operated on)

The reason is that we are using SCX_CALL_OP() instead of SCX_CALL_OP_TASK()
when calling ops.tick(), which triggers the error during the subsequent
scx_kf_allowed_on_arg_tasks() check.

SCX_CALL_OP_TASK() was first introduced in commit 36454023f5 ("sched_ext:
Track tasks that are subjects of the in-flight SCX operation") to ensure
task's rq lock is held when accessing task's sched_group. Since ops.tick()
is marked as SCX_KF_TERMINAL and task_tick_scx() is protected by the rq
lock, we can use SCX_CALL_OP_TASK() to avoid the above issue. Similarly,
the same changes should be made for ops.disable() and ops.exit_task(), as
they are also protected by task_rq_lock() and it's safe to access the
task's task_group.

Fixes: 36454023f5 ("sched_ext: Track tasks that are subjects of the in-flight SCX operation")
Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-13 06:57:33 -10:00
Tejun Heo
78e4690de4 Merge branch 'for-6.14-fixes' into for-6.15
Pull to receive f3f08c3acf ("sched_ext: Fix incorrect assumption about
migration disabled tasks in task_can_run_on_remote_rq()") which conflicts
with 26176116d9 ("sched_ext: Count SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE in
the right spot") in for-6.15.
2025-02-10 10:45:43 -10:00
Tejun Heo
f3f08c3acf sched_ext: Fix incorrect assumption about migration disabled tasks in task_can_run_on_remote_rq()
While fixing migration disabled task handling, 3296682157 ("sched_ext: Fix
migration disabled handling in targeted dispatches") assumed that a
migration disabled task's ->cpus_ptr would only have the pinned CPU. While
this is eventually true for migration disabled tasks that are switched out,
->cpus_ptr update is performed by migrate_disable_switch() which is called
right before context_switch() in __scheduler(). However, the task is
enqueued earlier during pick_next_task() via put_prev_task_scx(), so there
is a race window where another CPU can see the task on a DSQ.

If the CPU tries to dispatch the migration disabled task while in that
window, task_allowed_on_cpu() will succeed and task_can_run_on_remote_rq()
will subsequently trigger SCHED_WARN(is_migration_disabled()).

  WARNING: CPU: 8 PID: 1837 at kernel/sched/ext.c:2466 task_can_run_on_remote_rq+0x12e/0x140
  Sched_ext: layered (enabled+all), task: runnable_at=-10ms
  RIP: 0010:task_can_run_on_remote_rq+0x12e/0x140
  ...
   <TASK>
   consume_dispatch_q+0xab/0x220
   scx_bpf_dsq_move_to_local+0x58/0xd0
   bpf_prog_84dd17b0654b6cf0_layered_dispatch+0x290/0x1cfa
   bpf__sched_ext_ops_dispatch+0x4b/0xab
   balance_one+0x1fe/0x3b0
   balance_scx+0x61/0x1d0
   prev_balance+0x46/0xc0
   __pick_next_task+0x73/0x1c0
   __schedule+0x206/0x1730
   schedule+0x3a/0x160
   __do_sys_sched_yield+0xe/0x20
   do_syscall_64+0xbb/0x1e0
   entry_SYSCALL_64_after_hwframe+0x77/0x7f

Fix it by converting the SCHED_WARN() back to a regular failure path. Also,
perform the migration disabled test before task_allowed_on_cpu() test so
that BPF schedulers which fail to handle migration disabled tasks can be
noticed easily.

While at it, adjust scx_ops_error() message for !task_allowed_on_cpu() case
for brevity and consistency.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 3296682157 ("sched_ext: Fix migration disabled handling in targeted dispatches")
Acked-by: Andrea Righi <arighi@nvidia.com>
Reported-by: Jake Hillion <jakehillion@meta.com>
2025-02-10 10:40:47 -10:00
Li RongQing
1a4e0d8682 sched_ext: Take NUMA node into account when allocating per-CPU cpumasks
per-CPU cpumasks are dominantly accessed from their own local CPUs,
so allocate them node-local to improve performance.

Signed-off-by: Li RongQing <lirongqing@baidu.com>
Acked-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-10 07:20:13 -10:00
Tejun Heo
eace54dff0 sched_ext: Add SCX_EV_ENQ_SKIP_MIGRATION_DISABLED
Count the number of times a migration disabled task is automatically
dispatched to its local DSQ.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Changwoo Min <changwoo@igalia.com>
2025-02-08 20:39:11 -10:00
Tejun Heo
26176116d9 sched_ext: Count SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE in the right spot
SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE wasn't quite right in two aspects:

- It counted both migration disabled and offline events.

- It didn't count events from scx_bpf_dsq_move() path.

Fix it by moving the counting into task_can_run_on_remote_rq() which is
shared by both paths and can distinguish the different rejection conditions.
The argument @trigger_error is renamed to @enforce as it now does more than
just triggering error.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Changwoo Min <changwoo@igalia.com>
2025-02-08 20:39:11 -10:00
Tejun Heo
29ef4a2fcf Merge branch 'for-6.14-fixes' into for-6.15
Pull to receive:

- 2fa0fbeb69 ("sched_ext: Implement auto local dispatching of migration disabled tasks")
- 3296682157 ("sched_ext: Fix migration disabled handling in targeted dispatches")

as planned for-6.15 changes depend on them (e.g. adding event counter for
implicit migration disabled task handling).
2025-02-08 20:34:43 -10:00
Tejun Heo
3296682157 sched_ext: Fix migration disabled handling in targeted dispatches
A dispatch operation that can target a specific local DSQ -
scx_bpf_dsq_move_to_local() or scx_bpf_dsq_move() - checks whether the task
can be migrated to the target CPU using task_can_run_on_remote_rq(). If the
task can't be migrated to the targeted CPU, it is bounced through a global
DSQ.

task_can_run_on_remote_rq() assumes that the task is on a CPU that's
different from the targeted CPU but the callers doesn't uphold the
assumption and may call the function when the task is already on the target
CPU. When such task has migration disabled, task_can_run_on_remote_rq() ends
up returning %false incorrectly unnecessarily bouncing the task to a global
DSQ.

Fix it by updating the callers to only call task_can_run_on_remote_rq() when
the task is on a different CPU than the target CPU. As this is a bit subtle,
for clarity and documentation:

- Make task_can_run_on_remote_rq() trigger SCHED_WARN_ON() if the task is on
  the same CPU as the target CPU.

- is_migration_disabled() test in task_can_run_on_remote_rq() cannot trigger
  if the task is on a different CPU than the target CPU as the preceding
  task_allowed_on_cpu() test should fail beforehand. Convert the test into
  SCHED_WARN_ON().

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 4c30f5ce4f ("sched_ext: Implement scx_bpf_dispatch[_vtime]_from_dsq()")
Fixes: 0366017e09 ("sched_ext: Use task_can_run_on_remote_rq() test in dispatch_to_local_dsq()")
Cc: stable@vger.kernel.org # v6.12+
2025-02-08 20:33:25 -10:00
Tejun Heo
2fa0fbeb69 sched_ext: Implement auto local dispatching of migration disabled tasks
Migration disabled tasks are special and pinned to their previous CPUs. They
tripped up some unsuspecting BPF schedulers as their ->nr_cpus_allowed may
not agree with the bits set in ->cpus_ptr. Make it easier for BPF schedulers
by automatically dispatching them to the pinned local DSQs by default. If a
BPF scheduler wants to handle migration disabled tasks explicitly, it can
set SCX_OPS_ENQ_MIGRATION_DISABLED.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Andrea Righi <arighi@nvidia.com>
2025-02-08 20:32:54 -10:00
Changwoo Min
6d3f8fb4b2 sched_ext: Add an event, SCX_EV_ENQ_SLICE_DFL
Add a core event, SCX_EV_ENQ_SLICE_DFL, which represents how many
tasks have been enqueued (or pick_task-ed or select_cpu-ed) with
a default time slice (SCX_SLICE_DFL).

Scheduling a task with SCX_SLICE_DFL unintentionally would be a source
of latency spikes because SCX_SLICE_DFL is relatively long (20 msec).
Thus, soaring the SCX_EV_ENQ_SLICE_DFL value would be a sign of BPF
scheduler bugs, causing latency spikes, especially when ops.select_cpu()
is provided.

__scx_add_event() is used since the caller holds an rq lock or p->pi_lock,
so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-07 11:24:59 -10:00
Changwoo Min
d46457c31c sched_ext: Add an event, SCX_EV_BYPASS_DURATION
Add a core event, SCX_EV_BYPASS_DURATION, which represents the
total duration of bypass modes in nanoseconds.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-04 10:36:47 -10:00
Changwoo Min
5c605cd33c sched_ext: Add an event, SCX_EV_BYPASS_DISPATCH
Add a core event, SCX_EV_BYPASS_DISPATCH, which represents how many
tasks have been dispatched in the bypass mode.

__scx_add_event() is used since the caller holds an rq lock or
p->pi_lock, so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-04 10:36:47 -10:00
Changwoo Min
4f7a38c7c9 sched_ext: Add an event, SCX_EV_BYPASS_ACTIVATE
Add a core event, SCX_EV_BYPASS_ACTIVATE, which represents how many
times the bypass mode has been triggered.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-04 10:36:47 -10:00
Changwoo Min
824d4f2dce sched_ext: Add an event, SCX_EV_ENQ_SKIP_EXITING
Add a core event, SCX_EV_ENQ_SKIP_EXITING, which represents how many
times a task is enqueued to a local DSQ when exiting if
SCX_OPS_ENQ_EXITING is not set.

__scx_add_event() is used since the caller holds an rq lock,
so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-04 10:36:47 -10:00
Changwoo Min
7125660bc1 sched_ext: Add an event, SCX_EV_DISPATCH_KEEP_LAST
Add a core event, SCX_EV_DISPATCH_KEEP_LAST, which represents how many
times a task is continued to run without ops.enqueue() when
SCX_OPS_ENQ_LAST is not set.

__scx_add_event() is used since the caller holds an rq lock,
so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-02 07:23:18 -10:00
Changwoo Min
9be0a1b0c8 sched_ext: Add an event, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE
Add a core event, SCX_EV_DISPATCH_LOCAL_DSQ_OFFLINE, which represents how
many times a BPF scheduler tries to dispatch to an offlined local DSQ.

__scx_add_event() is used since the caller holds an rq lock,
so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-02 07:23:18 -10:00
Changwoo Min
f7f6142107 sched_ext: Add an event, SCX_EV_SELECT_CPU_FALLBACK
Add a core event, SCX_EV_SELECT_CPU_FALLBACK, which represents how many times
ops.select_cpu() returns a CPU that the task can't use.

__scx_add_event() is used since the caller holds an rq lock,
so the preemption has already been disabled.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-02 07:23:18 -10:00
Changwoo Min
17103b8504 sched_ext: Implement event counter infrastructure
Collect the statistics of specific types of behavior in the sched_ext core,
which are not easily visible but still interesting to an scx scheduler.

An event type is defined in 'struct scx_event_stats.' When an event occurs,
its counter is accumulated using 'scx_add_event()' and '__scx_add_event()'
to per-CPU 'struct scx_event_stats' for efficiency. 'scx_bpf_events()'
aggregates all the per-CPU counters and exposes a system-wide counters.

For convenience and readability of the code, 'scx_agg_event()' and
'scx_dump_event()' are provided.

The collected events can be observed after a BPF scheduler is unloaded
beforea new BPF scheduler is loaded so the per-CPU 'struct scx_event_stats'
are reset.

Signed-off-by: Changwoo Min <changwoo@igalia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-02-02 07:23:18 -10:00
Andrea Righi
337d1b354a sched_ext: Move built-in idle CPU selection policy to a separate file
As ext.c is becoming quite large, move the idle CPU selection policy to
separate files (ext_idle.c / ext_idle.h) for better code readability.

Moreover, group together all the idle CPU selection kfunc's to the same
btf_kfunc_id_set block.

No functional changes, this is purely code reorganization.

Suggested-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-01-27 12:43:43 -10:00
Andrea Righi
1626e5ef0b sched_ext: Fix lock imbalance in dispatch_to_local_dsq()
While performing the rq locking dance in dispatch_to_local_dsq(), we may
trigger the following lock imbalance condition, in particular when
multiple tasks are rapidly changing CPU affinity (i.e., running a
`stress-ng --race-sched 0`):

[   13.413579] =====================================
[   13.413660] WARNING: bad unlock balance detected!
[   13.413729] 6.13.0-virtme #15 Not tainted
[   13.413792] -------------------------------------
[   13.413859] kworker/1:1/80 is trying to release lock (&rq->__lock) at:
[   13.413954] [<ffffffff873c6c48>] dispatch_to_local_dsq+0x108/0x1a0
[   13.414111] but there are no more locks to release!
[   13.414176]
[   13.414176] other info that might help us debug this:
[   13.414258] 1 lock held by kworker/1:1/80:
[   13.414318]  #0: ffff8b66feb41698 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x20/0x90
[   13.414612]
[   13.414612] stack backtrace:
[   13.415255] CPU: 1 UID: 0 PID: 80 Comm: kworker/1:1 Not tainted 6.13.0-virtme #15
[   13.415505] Workqueue:  0x0 (events)
[   13.415567] Sched_ext: dsp_local_on (enabled+all), task: runnable_at=-2ms
[   13.415570] Call Trace:
[   13.415700]  <TASK>
[   13.415744]  dump_stack_lvl+0x78/0xe0
[   13.415806]  ? dispatch_to_local_dsq+0x108/0x1a0
[   13.415884]  print_unlock_imbalance_bug+0x11b/0x130
[   13.415965]  ? dispatch_to_local_dsq+0x108/0x1a0
[   13.416226]  lock_release+0x231/0x2c0
[   13.416326]  _raw_spin_unlock+0x1b/0x40
[   13.416422]  dispatch_to_local_dsq+0x108/0x1a0
[   13.416554]  flush_dispatch_buf+0x199/0x1d0
[   13.416652]  balance_one+0x194/0x370
[   13.416751]  balance_scx+0x61/0x1e0
[   13.416848]  prev_balance+0x43/0xb0
[   13.416947]  __pick_next_task+0x6b/0x1b0
[   13.417052]  __schedule+0x20d/0x1740

This happens because dispatch_to_local_dsq() is racing with
dispatch_dequeue() and, when the latter wins, we incorrectly assume that
the task has been moved to dst_rq.

Fix by properly tracking the currently locked rq.

Fixes: 4d3ca89bdd ("sched_ext: Refactor consume_remote_task()")
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-01-27 12:41:12 -10:00
Tejun Heo
d6f3e7d564 sched_ext: Fix incorrect autogroup migration detection
scx_move_task() is called from sched_move_task() and tells the BPF scheduler
that cgroup migration is being committed. sched_move_task() is used by both
cgroup and autogroup migrations and scx_move_task() tried to filter out
autogroup migrations by testing the destination cgroup and PF_EXITING but
this is not enough. In fact, without explicitly tagging the thread which is
doing the cgroup migration, there is no good way to tell apart
scx_move_task() invocations for racing migration to the root cgroup and an
autogroup migration.

This led to scx_move_task() incorrectly ignoring a migration from non-root
cgroup to an autogroup of the root cgroup triggering the following warning:

  WARNING: CPU: 7 PID: 1 at kernel/sched/ext.c:3725 scx_cgroup_can_attach+0x196/0x340
  ...
  Call Trace:
  <TASK>
    cgroup_migrate_execute+0x5b1/0x700
    cgroup_attach_task+0x296/0x400
    __cgroup_procs_write+0x128/0x140
    cgroup_procs_write+0x17/0x30
    kernfs_fop_write_iter+0x141/0x1f0
    vfs_write+0x31d/0x4a0
    __x64_sys_write+0x72/0xf0
    do_syscall_64+0x82/0x160
    entry_SYSCALL_64_after_hwframe+0x76/0x7e

Fix it by adding an argument to sched_move_task() that indicates whether the
moving is for a cgroup or autogroup migration. After the change,
scx_move_task() is called only for cgroup migrations and renamed to
scx_cgroup_move_task().

Link: https://github.com/sched-ext/scx/issues/370
Fixes: 8195136669 ("sched_ext: Add cgroup support")
Cc: stable@vger.kernel.org # v6.12+
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-01-27 08:31:50 -10:00
Andrea Righi
2279563e3a sched_ext: Include task weight in the error state dump
Report the task weight when dumping the task state during an error exit.
Moreover, adjust the output format to display dsq_vtime, slice, and
weight on the same line.

This can help identify whether certain tasks were excessively
prioritized or de-prioritized due to large niceness gaps.

Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-01-24 08:07:42 -10:00
Atul Kumar Pant
be8ee18152 sched_ext: Fixes typos in comments
Fixes some spelling errors in the comments.

Signed-off-by: Atul Kumar Pant <atulpant.linux@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2025-01-24 08:06:05 -10:00
Linus Torvalds
454cb97726 Merge tag 'v6.14-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto updates from Herbert Xu:
 "API:
   - Remove physical address skcipher walking
   - Fix boot-up self-test race

  Algorithms:
   - Optimisations for x86/aes-gcm
   - Optimisations for x86/aes-xts
   - Remove VMAC
   - Remove keywrap

  Drivers:
   - Remove n2

  Others:
   - Fixes for padata UAF
   - Fix potential rhashtable deadlock by moving schedule_work outside
     lock"

* tag 'v6.14-p1' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (75 commits)
  rhashtable: Fix rhashtable_try_insert test
  dt-bindings: crypto: qcom,inline-crypto-engine: Document the SM8750 ICE
  dt-bindings: crypto: qcom,prng: Document SM8750 RNG
  dt-bindings: crypto: qcom-qce: Document the SM8750 crypto engine
  crypto: asymmetric_keys - Remove unused key_being_used_for[]
  padata: avoid UAF for reorder_work
  padata: fix UAF in padata_reorder
  padata: add pd get/put refcnt helper
  crypto: skcipher - call cond_resched() directly
  crypto: skcipher - optimize initializing skcipher_walk fields
  crypto: skcipher - clean up initialization of skcipher_walk::flags
  crypto: skcipher - fold skcipher_walk_skcipher() into skcipher_walk_virt()
  crypto: skcipher - remove redundant check for SKCIPHER_WALK_SLOW
  crypto: skcipher - remove redundant clamping to page size
  crypto: skcipher - remove unnecessary page alignment of bounce buffer
  crypto: skcipher - document skcipher_walk_done() and rename some vars
  crypto: omap - switch from scatter_walk to plain offset
  crypto: powerpc/p10-aes-gcm - simplify handling of linear associated data
  crypto: bcm - Drop unused setting of local 'ptr' variable
  crypto: hisilicon/qm - support new function communication
  ...
2025-01-24 07:48:10 -08:00
Linus Torvalds
5b7f7234ff Merge tag 'x86-boot-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 boot updates from Ingo Molnar:

 - A large and involved preparatory series to pave the way to add
   exception handling for relocate_kernel - which will be a debugging
   facility that has aided in the field to debug an exceptionally hard
   to debug early boot bug. Plus assorted cleanups and fixes that were
   discovered along the way, by David Woodhouse:

      - Clean up and document register use in relocate_kernel_64.S
      - Use named labels in swap_pages in relocate_kernel_64.S
      - Only swap pages for ::preserve_context mode
      - Allocate PGD for x86_64 transition page tables separately
      - Copy control page into place in machine_kexec_prepare()
      - Invoke copy of relocate_kernel() instead of the original
      - Move relocate_kernel to kernel .data section
      - Add data section to relocate_kernel
      - Drop page_list argument from relocate_kernel()
      - Eliminate writes through kernel mapping of relocate_kernel page
      - Clean up register usage in relocate_kernel()
      - Mark relocate_kernel page as ROX instead of RWX
      - Disable global pages before writing to control page
      - Ensure preserve_context flag is set on return to kernel
      - Use correct swap page in swap_pages function
      - Fix stack and handling of re-entry point for ::preserve_context
      - Mark machine_kexec() with __nocfi
      - Cope with relocate_kernel() not being at the start of the page
      - Use typedef for relocate_kernel_fn function prototype
      - Fix location of relocate_kernel with -ffunction-sections (fix by Nathan Chancellor)

 - A series to remove the last remaining absolute symbol references from
   .head.text, and enforce this at build time, by Ard Biesheuvel:

      - Avoid WARN()s and panic()s in early boot code
      - Don't hang but terminate on failure to remap SVSM CA
      - Determine VA/PA offset before entering C code
      - Avoid intentional absolute symbol references in .head.text
      - Disable UBSAN in early boot code
      - Move ENTRY_TEXT to the start of the image
      - Move .head.text into its own output section
      - Reject absolute references in .head.text

 - The above build-time enforcement uncovered a handful of bugs of
   essentially non-working code, and a wrokaround for a toolchain bug,
   fixed by Ard Biesheuvel as well:

      - Fix spurious undefined reference when CONFIG_X86_5LEVEL=n, on GCC-12
      - Disable UBSAN on SEV code that may execute very early
      - Disable ftrace branch profiling in SEV startup code

 - And miscellaneous cleanups:

      - kexec_core: Add and update comments regarding the KEXEC_JUMP flow (Rafael J. Wysocki)
      - x86/sysfs: Constify 'struct bin_attribute' (Thomas Weißschuh)"

* tag 'x86-boot-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  x86/sev: Disable ftrace branch profiling in SEV startup code
  x86/kexec: Use typedef for relocate_kernel_fn function prototype
  x86/kexec: Cope with relocate_kernel() not being at the start of the page
  kexec_core: Add and update comments regarding the KEXEC_JUMP flow
  x86/kexec: Mark machine_kexec() with __nocfi
  x86/kexec: Fix location of relocate_kernel with -ffunction-sections
  x86/kexec: Fix stack and handling of re-entry point for ::preserve_context
  x86/kexec: Use correct swap page in swap_pages function
  x86/kexec: Ensure preserve_context flag is set on return to kernel
  x86/kexec: Disable global pages before writing to control page
  x86/sev: Don't hang but terminate on failure to remap SVSM CA
  x86/sev: Disable UBSAN on SEV code that may execute very early
  x86/boot/64: Fix spurious undefined reference when CONFIG_X86_5LEVEL=n, on GCC-12
  x86/sysfs: Constify 'struct bin_attribute'
  x86/kexec: Mark relocate_kernel page as ROX instead of RWX
  x86/kexec: Clean up register usage in relocate_kernel()
  x86/kexec: Eliminate writes through kernel mapping of relocate_kernel page
  x86/kexec: Drop page_list argument from relocate_kernel()
  x86/kexec: Add data section to relocate_kernel
  x86/kexec: Move relocate_kernel to kernel .data section
  ...
2025-01-24 05:54:26 -08:00
Linus Torvalds
bc8198dc7e Merge tag 'sched_ext-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext updates from Tejun Heo:

 - scx_bpf_now() added so that BPF scheduler can access the cached
   timestamp in struct rq to avoid reading TSC multiple times within a
   locked scheduling operation.

 - Minor updates to the built-in idle CPU selection logic.

 - tool/sched_ext updates and other misc changes.

* tag 'sched_ext-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: fix kernel-doc warnings
  sched_ext: Use time helpers in BPF schedulers
  sched_ext: Replace bpf_ktime_get_ns() to scx_bpf_now()
  sched_ext: Add time helpers for BPF schedulers
  sched_ext: Add scx_bpf_now() for BPF scheduler
  sched_ext: Implement scx_bpf_now()
  sched_ext: Relocate scx_enabled() related code
  sched_ext: Add option -l in selftest runner to list all available tests
  sched_ext: Include remaining task time slice in error state dump
  sched_ext: update scx_bpf_dsq_insert() doc for SCX_DSQ_LOCAL_ON
  sched_ext: idle: small CPU iteration refactoring
  sched_ext: idle: introduce check_builtin_idle_enabled() helper
  sched_ext: idle: clarify comments
  sched_ext: idle: use assign_cpu() to update the idle cpumask
  sched_ext: Use str_enabled_disabled() helper in update_selcpu_topology()
  sched_ext: Use sizeof_field for key_len in dsq_hash_params
  tools/sched_ext: Receive updates from SCX repo
  sched_ext: Use the NUMA scheduling domain for NUMA optimizations
2025-01-23 18:49:43 -08:00
Linus Torvalds
606489dbfa Merge tag 'trace-ringbuffer-v6.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull trace fing buffer fix from Steven Rostedt:
 "Fix atomic64 operations on some architectures for the tracing ring
  buffer:

   - Have emulating atomic64 use arch_spin_locks instead of
     raw_spin_locks

     The tracing ring buffer events have a small timestamp that holds
     the delta between itself and the event before it. But this can be
     tricky to update when interrupts come in. It originally just set
     the deltas to zero for events that interrupted the adding of
     another event which made all the events in the interrupt have the
     same timestamp as the event it interrupted. This was not suitable
     for many tools, so it was eventually fixed. But that fix required
     adding an atomic64 cmpxchg on the timestamp in cases where an event
     was added while another event was in the process of being added.

     Originally, for 32 bit architectures, the manipulation of the 64
     bit timestamp was done by a structure that held multiple 32bit
     words to hold parts of the timestamp and a counter. But as updates
     to the ring buffer were done, maintaining this became too complex
     and was replaced by the atomic64 generic operations which are now
     used by both 64bit and 32bit architectures. Shortly after that, it
     was reported that riscv32 and other 32 bit architectures that just
     used the generic atomic64 were locking up. This was because the
     generic atomic64 operations defined in lib/atomic64.c uses a
     raw_spin_lock() to emulate an atomic64 operation. The problem here
     was that raw_spin_lock() can also be traced by the function tracer
     (which is commonly used for debugging raw spin locks). Since the
     function tracer uses the tracing ring buffer, which now is being
     traced internally, this was triggering a recursion and setting off
     a warning that the spin locks were recusing.

     There's no reason for the code that emulates atomic64 operations to
     be using raw_spin_locks which have a lot of debugging
     infrastructure attached to them (depending on the config options).
     Instead it should be using the arch_spin_lock() which does not have
     any infrastructure attached to them and is used by low level
     infrastructure like RCU locks, lockdep and of course tracing. Using
     arch_spin_lock()s fixes this issue.

   - Do not trace in NMI if the architecture uses emulated atomic64
     operations

     Another issue with using the emulated atomic64 operations that uses
     spin locks to emulate the atomic64 operations is that they cannot
     be used in NMI context. As an NMI can trigger while holding the
     atomic64 spin locks it can try to take the same lock and cause a
     deadlock.

     Have the ring buffer fail recording events if in NMI context and
     the architecture uses the emulated atomic64 operations"

* tag 'trace-ringbuffer-v6.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  atomic64: Use arch_spin_locks instead of raw_spin_locks
  ring-buffer: Do not allow events in NMI with generic atomic64 cmpxchg()
2025-01-23 18:02:55 -08:00
Linus Torvalds
7c1badb2a9 Merge tag 'ftrace-v6.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull fgraph updates from Steven Rostedt:
 "Remove calltime and rettime from fgraph infrastructure

  The calltime and rettime were used by the function graph tracer to
  calculate the timings of functions where it traced their entry and
  exit. The calltime and rettime were stored in the generic structures
  that were used for the mechanisms to add an entry and exit callback.

  Now that function graph infrastructure is used by other subsystems
  than just the tracer, the calltime and rettime are not needed for
  them. Remove the calltime and rettime from the generic fgraph
  infrastructure and have the callers that require them handle them"

* tag 'ftrace-v6.14-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  fgraph: Remove calltime and rettime from generic operations
2025-01-23 17:59:25 -08:00
Linus Torvalds
e8744fbc83 Merge tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing updates from Steven Rostedt:

 - Cleanup with guard() and free() helpers

   There were several places in the code that had a lot of "goto out" in
   the error paths to either unlock a lock or free some memory that was
   allocated. But this is error prone. Convert the code over to use the
   guard() and free() helpers that let the compiler unlock locks or free
   memory when the function exits.

 - Update the Rust tracepoint code to use the C code too

   There was some duplication of the tracepoint code for Rust that did
   the same logic as the C code. Add a helper that makes it possible for
   both algorithms to use the same logic in one place.

 - Add poll to trace event hist files

   It is useful to know when an event is triggered, or even with some
   filtering. Since hist files of events get updated when active and the
   event is triggered, allow applications to poll the hist file and wake
   up when an event is triggered. This will let the application know
   that the event it is waiting for happened.

 - Add :mod: command to enable events for current or future modules

   The function tracer already has a way to enable functions to be
   traced in modules by writing ":mod:<module>" into set_ftrace_filter.
   That will enable either all the functions for the module if it is
   loaded, or if it is not, it will cache that command, and when the
   module is loaded that matches <module>, its functions will be
   enabled. This also allows init functions to be traced. But currently
   events do not have that feature.

   Add the command where if ':mod:<module>' is written into set_event,
   then either all the modules events are enabled if it is loaded, or
   cache it so that the module's events are enabled when it is loaded.
   This also works from the kernel command line, where
   "trace_event=:mod:<module>", when the module is loaded at boot up,
   its events will be enabled then.

* tag 'trace-v6.14-3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (26 commits)
  tracing: Fix output of set_event for some cached module events
  tracing: Fix allocation of printing set_event file content
  tracing: Rename update_cache() to update_mod_cache()
  tracing: Fix #if CONFIG_MODULES to #ifdef CONFIG_MODULES
  selftests/ftrace: Add test that tests event :mod: commands
  tracing: Cache ":mod:" events for modules not loaded yet
  tracing: Add :mod: command to enabled module events
  selftests/tracing: Add hist poll() support test
  tracing/hist: Support POLLPRI event for poll on histogram
  tracing/hist: Add poll(POLLIN) support on hist file
  tracing: Fix using ret variable in tracing_set_tracer()
  tracepoint: Reduce duplication of __DO_TRACE_CALL
  tracing/string: Create and use __free(argv_free) in trace_dynevent.c
  tracing: Switch trace_stat.c code over to use guard()
  tracing: Switch trace_stack.c code over to use guard()
  tracing: Switch trace_osnoise.c code over to use guard() and __free()
  tracing: Switch trace_events_synth.c code over to use guard()
  tracing: Switch trace_events_filter.c code over to use guard()
  tracing: Switch trace_events_trigger.c code over to use guard()
  tracing: Switch trace_events_hist.c code over to use guard()
  ...
2025-01-23 17:51:16 -08:00
Linus Torvalds
544521d621 Merge tag 'probes-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull probes updates from Masami Hiramatsu:

 - kprobes: Cleanups using guard() and __free(): Use cleanup.h macros to
   cleanup code and remove all gotos from kprobes code.

 - tracing/probes: Also cleanups tracing/*probe events code with guard()
   and __free(). These patches are just to simplify the parser codes.

 - kprobes: Reduce preempt disable scope in check_kprobe_access_safe()

   This reduces preempt disable time to only when getting the module
   refcount in check_kprobe_access_safe().

   Previously it disabled preempt needlessly for other checks including
   jump_label_text_reserved(), which took a long time because of the
   linear search.

* tag 'probes-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing/kprobes: Simplify __trace_kprobe_create() by removing gotos
  tracing: Use __free() for kprobe events to cleanup
  tracing: Use __free() in trace_probe for cleanup
  kprobes: Remove remaining gotos
  kprobes: Remove unneeded goto
  kprobes: Use guard for rcu_read_lock
  kprobes: Use guard() for external locks
  jump_label: Define guard() for jump_label_lock
  tracing/eprobe: Adopt guard() and scoped_guard()
  tracing/uprobe: Adopt guard() and scoped_guard()
  tracing/kprobe: Adopt guard() and scoped_guard()
  kprobes: Adopt guard() and scoped_guard()
  kprobes: Reduce preempt disable scope in check_kprobe_access_safe()
2025-01-23 17:24:20 -08:00
Linus Torvalds
8883957b3c Merge tag 'fsnotify_hsm_for_v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull fsnotify pre-content notification support from Jan Kara:
 "This introduces a new fsnotify event (FS_PRE_ACCESS) that gets
  generated before a file contents is accessed.

  The event is synchronous so if there is listener for this event, the
  kernel waits for reply. On success the execution continues as usual,
  on failure we propagate the error to userspace. This allows userspace
  to fill in file content on demand from slow storage. The context in
  which the events are generated has been picked so that we don't hold
  any locks and thus there's no risk of a deadlock for the userspace
  handler.

  The new pre-content event is available only for users with global
  CAP_SYS_ADMIN capability (similarly to other parts of fanotify
  functionality) and it is an administrator responsibility to make sure
  the userspace event handler doesn't do stupid stuff that can DoS the
  system.

  Based on your feedback from the last submission, fsnotify code has
  been improved and now file->f_mode encodes whether pre-content event
  needs to be generated for the file so the fast path when nobody wants
  pre-content event for the file just grows the additional file->f_mode
  check. As a bonus this also removes the checks whether the old
  FS_ACCESS event needs to be generated from the fast path. Also the
  place where the event is generated during page fault has been moved so
  now filemap_fault() generates the event if and only if there is no
  uptodate folio in the page cache.

  Also we have dropped FS_PRE_MODIFY event as current real-world users
  of the pre-content functionality don't really use it so let's start
  with the minimal useful feature set"

* tag 'fsnotify_hsm_for_v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: (21 commits)
  fanotify: Fix crash in fanotify_init(2)
  fs: don't block write during exec on pre-content watched files
  fs: enable pre-content events on supported file systems
  ext4: add pre-content fsnotify hook for DAX faults
  btrfs: disable defrag on pre-content watched files
  xfs: add pre-content fsnotify hook for DAX faults
  fsnotify: generate pre-content permission event on page fault
  mm: don't allow huge faults for files with pre content watches
  fanotify: disable readahead if we have pre-content watches
  fanotify: allow to set errno in FAN_DENY permission response
  fanotify: report file range info with pre-content events
  fanotify: introduce FAN_PRE_ACCESS permission event
  fsnotify: generate pre-content permission event on truncate
  fsnotify: pass optional file access range in pre-content event
  fsnotify: introduce pre-content permission events
  fanotify: reserve event bit of deprecated FAN_DIR_MODIFY
  fanotify: rename a misnamed constant
  fanotify: don't skip extra event info if no info_mode is set
  fsnotify: check if file is actually being watched for pre-content events on open
  fsnotify: opt-in for permission events at file open time
  ...
2025-01-23 13:36:06 -08:00
Linus Torvalds
d0d106a2bd Merge tag 'bpf-next-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Pull bpf updates from Alexei Starovoitov:
 "A smaller than usual release cycle.

  The main changes are:

   - Prepare selftest to run with GCC-BPF backend (Ihor Solodrai)

     In addition to LLVM-BPF runs the BPF CI now runs GCC-BPF in compile
     only mode. Half of the tests are failing, since support for
     btf_decl_tag is still WIP, but this is a great milestone.

   - Convert various samples/bpf to selftests/bpf/test_progs format
     (Alexis Lothoré and Bastien Curutchet)

   - Teach verifier to recognize that array lookup with constant
     in-range index will always succeed (Daniel Xu)

   - Cleanup migrate disable scope in BPF maps (Hou Tao)

   - Fix bpf_timer destroy path in PREEMPT_RT (Hou Tao)

   - Always use bpf_mem_alloc in bpf_local_storage in PREEMPT_RT (Martin
     KaFai Lau)

   - Refactor verifier lock support (Kumar Kartikeya Dwivedi)

     This is a prerequisite for upcoming resilient spin lock.

   - Remove excessive 'may_goto +0' instructions in the verifier that
     LLVM leaves when unrolls the loops (Yonghong Song)

   - Remove unhelpful bpf_probe_write_user() warning message (Marco
     Elver)

   - Add fd_array_cnt attribute for prog_load command (Anton Protopopov)

     This is a prerequisite for upcoming support for static_branch"

* tag 'bpf-next-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (125 commits)
  selftests/bpf: Add some tests related to 'may_goto 0' insns
  bpf: Remove 'may_goto 0' instruction in opt_remove_nops()
  bpf: Allow 'may_goto 0' instruction in verifier
  selftests/bpf: Add test case for the freeing of bpf_timer
  bpf: Cancel the running bpf_timer through kworker for PREEMPT_RT
  bpf: Free element after unlock in __htab_map_lookup_and_delete_elem()
  bpf: Bail out early in __htab_map_lookup_and_delete_elem()
  bpf: Free special fields after unlock in htab_lru_map_delete_node()
  tools: Sync if_xdp.h uapi tooling header
  libbpf: Work around kernel inconsistently stripping '.llvm.' suffix
  bpf: selftests: verifier: Add nullness elision tests
  bpf: verifier: Support eliding map lookup nullness
  bpf: verifier: Refactor helper access type tracking
  bpf: tcp: Mark bpf_load_hdr_opt() arg2 as read-write
  bpf: verifier: Add missing newline on verbose() call
  selftests/bpf: Add distilled BTF test about marking BTF_IS_EMBEDDED
  libbpf: Fix incorrect traversal end type ID when marking BTF_IS_EMBEDDED
  libbpf: Fix return zero when elf_begin failed
  selftests/bpf: Fix btf leak on new btf alloc failure in btf_distill test
  veristat: Load struct_ops programs only once
  ...
2025-01-23 08:04:07 -08:00
Linus Torvalds
5ab889facc Merge tag 'hardening-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull hardening updates from Kees Cook:

 - stackleak: Use str_enabled_disabled() helper (Thorsten Blum)

 - Document GCC INIT_STACK_ALL_PATTERN behavior (Geert Uytterhoeven)

 - Add task_prctl_unknown tracepoint (Marco Elver)

* tag 'hardening-v6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  hardening: Document INIT_STACK_ALL_PATTERN behavior with GCC
  stackleak: Use str_enabled_disabled() helper in stack_erasing_sysctl()
  tracing: Remove pid in task_rename tracing output
  tracing: Add task_prctl_unknown tracepoint
2025-01-22 20:29:53 -08:00
Linus Torvalds
f4b9d3bf44 Merge tag 'pm-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
 "The majority of changes here are cpufreq updates which are dominated
  by amd-pstate driver changes, like in the previous cycle. Moreover,
  changes related to amd-pstate are also the majority of cpupower
  utility updates.

  Included are some pieces of new hardware support, like the addition of
  Clearwater Forest processors support to intel_idle, new cpufreq driver
  for Airoha SoCs, and Apple cpufreq driver extensions to support more
  SoCs. The intel_pstate driver is also extended to be able to support
  new platforms by using ACPI CPPC to compute scaling factors between
  HWP performance states and frequency.

  The rest is mostly fixes and cleanups in assorted pieces of power
  management code.

  Specifics:

   - Use str_enable_disable()-like helpers in cpufreq (Krzysztof
     Kozlowski)

   - Extend the Apple cpufreq driver to support more SoCs (Hector
     Martin, Nick Chan)

   - Add new cpufreq driver for Airoha SoCs (Christian Marangi)

   - Fix using cpufreq-dt as module (Andreas Kemnade)

   - Minor fixes for Sparc, SCMI, and Qcom cpufreq drivers (Ethan Carter
     Edwards, Sibi Sankar, Manivannan Sadhasivam)

   - Fix the maximum supported frequency computation in the ACPI cpufreq
     driver to avoid relying on unfounded assumptions (Gautham Shenoy)

   - Fix an amd-pstate driver regression with preferred core rankings
     not being used (Mario Limonciello)

   - Fix a precision issue with frequency calculation in the amd-pstate
     driver (Naresh Solanki)

   - Add ftrace event to the amd-pstate driver for active mode (Mario
     Limonciello)

   - Set default EPP policy on Ryzen processors in amd-pstate (Mario
     Limonciello)

   - Clean up the amd-pstate cpufreq driver and optimize it to increase
     code reuse (Mario Limonciello, Dhananjay Ugwekar)

   - Use CPPC to get scaling factors between HWP performance levels and
     frequency in the intel_pstate driver and make it stop using a
     built-in scaling factor for Arrow Lake processors (Rafael Wysocki)

   - Make intel_pstate initialize epp_policy to CPUFREQ_POLICY_UNKNOWN
     for consistency with CPU offline (Christian Loehle)

   - Fix superfluous updates caused by need_freq_update in the schedutil
     cpufreq governor (Sultan Alsawaf)

   - Allow configuring the system suspend-resume (DPM) watchdog to warn
     earlier than panic (Douglas Anderson)

   - Implement devm_device_init_wakeup() helper and introduce a device-
     managed variant of dev_pm_set_wake_irq() (Joe Hattori, Peng Fan)

   - Remove direct inclusions of 'pm_wakeup.h' which should be only
     included via 'device.h' (Wolfram Sang)

   - Clean up two comments in the core system-wide PM code (Rafael
     Wysocki, Randy Dunlap)

   - Add Clearwater Forest processor support to the intel_idle cpuidle
     driver (Artem Bityutskiy)

   - Clean up the Exynos devfreq driver and devfreq core (Markus
     Elfring, Jeongjun Park)

   - Minor cleanups and fixes for OPP (Dan Carpenter, Neil Armstrong,
     Joe Hattori)

   - Implement dev_pm_opp_get_bw() (Neil Armstrong)

   - Expose OPP reference counting helpers for Rust (Viresh Kumar)

   - Fix TSC MHz calculation in cpupower (He Rongguang)

   - Add install and uninstall options to bindings Makefile and add
     header changes for cpufreq.h to SWIG bindings in cpupower (John B.
     Wyatt IV)

   - Add missing residency header changes in cpuidle.h to SWIG bindings
     in cpupower (John B. Wyatt IV)

   - Add output files to .gitignore and clean them up in "make clean" in
     selftests/cpufreq (Li Zhijian)

   - Fix cross-compilation in cpupower Makefile (Peng Fan)

   - Revise the is_valid flag handling for idle_monitor in the cpupower
     utility (wangfushuai)

   - Extend and clean up AMD processors support in cpupower (Mario
     Limonciello)"

* tag 'pm-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (67 commits)
  PM / OPP: Add reference counting helpers for Rust implementation
  PM: sleep: wakeirq: Introduce device-managed variant of dev_pm_set_wake_irq()
  cpufreq: Use str_enable_disable()-like helpers
  cpufreq: airoha: Add EN7581 CPUFreq SMCCC driver
  PM: sleep: Allow configuring the DPM watchdog to warn earlier than panic
  PM: sleep: convert comment from kernel-doc to plain comment
  cpufreq: ACPI: Fix max-frequency computation
  pm: cpupower: Add missing residency header changes in cpuidle.h to SWIG
  PM / devfreq: exynos: remove unused function parameter
  OPP: OF: Fix an OF node leak in _opp_add_static_v2()
  cpufreq/amd-pstate: Refactor max frequency calculation
  cpufreq/amd-pstate: Fix prefcore rankings
  pm: cpupower: Add header changes for cpufreq.h to SWIG bindings
  cpufreq: sparc: change kzalloc to kcalloc
  cpufreq: qcom: Implement clk_ops::determine_rate() for qcom_cpufreq* clocks
  cpufreq: qcom: Fix qcom_cpufreq_hw_recalc_rate() to query LUT if LMh IRQ is not available
  cpufreq: apple-soc: Add Apple A7-A8X SoC cpufreq support
  cpufreq: apple-soc: Set fallback transition latency to APPLE_DVFS_TRANSITION_TIMEOUT
  cpufreq: apple-soc: Increase cluster switch timeout to 400us
  cpufreq: apple-soc: Use 32-bit read for status register
  ...
2025-01-22 11:16:14 -08:00