sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted

alb_break_llc() decides whether to break LLC preference during active
load balance. It does so by testing that every runnable fair task on the
source rq prefers its LLC:

	env->src_rq->nr_pref_llc_running == env->src_rq->cfs.h_nr_runnable

But the two counters cover different sets. nr_pref_llc_running is updated
in account_llc_enqueue()/account_llc_dequeue(), next to cfs_rq->nr_queued,
so it follows queued tasks. h_nr_runnable is updated in set_delayed()/
clear_delayed() and drops delay-dequeued tasks.

So under DELAY_DEQUEUE, a preferring task that goes to sleep stays counted
in nr_pref_llc_running while h_nr_runnable falls. The equality then breaks,
alb_break_llc() returns false, and active balance is free to pull a task
off its preferred LLC. Active balance only moves runnable tasks, and this
is the only LLC check it consults: once the stopper runs, LBF_ACTIVE_LB
skips the per-task test in can_migrate_task(). The runnable set is the one
we want.

Fix it on the counter side. A task should be counted in
nr_pref_llc_running exactly while it is both queued on its preferred LLC
(pref_llc_queued) and runnable (!sched_delayed). Define that membership
once in task_pref_llc_runnable(), and adjust the counter only through
pref_llc_running_inc()/pref_llc_running_dec() from the four sites that
change either input: account_llc_enqueue(), account_llc_dequeue(),
set_delayed() and clear_delayed(). Gating every update on the same
predicate keeps the delay, wake and dequeue paths from double-counting
or underflowing; see the comments at those sites for the ordering.

nr_llc_running and sd->llc_counts are not touched and stay on queued
semantics.

Fixes: 714059f79ff0 ("sched/cache: Handle moving single tasks to/from their preferred LLC")
Closes: https://lore.kernel.org/lkml/20260827135000.735138-1-zhanxusheng@xiaomi.com/
Reported-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com

1 files changed, 229 insertions, 0 deletions

diff --git a/sound/soc/sof/control.c b/sound/soc/sof/control.c
new file mode 100644
index 000000000..74d997a4f
--- /dev/null
+++ b/sound/soc/sof/control.c
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+
+/* Mixer Controls */
+
+#include <linux/pm_runtime.h>
+#include <linux/leds.h>
+#include "sof-priv.h"
+#include "sof-audio.h"
+
+int snd_sof_volume_get(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_mixer_control *sm = (struct soc_mixer_control *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = sm->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->volume_get)
+		return tplg_ops->control->volume_get(scontrol, ucontrol);
+
+	return 0;
+}
+
+int snd_sof_volume_put(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_mixer_control *sm = (struct soc_mixer_control *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = sm->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->volume_put)
+		return tplg_ops->control->volume_put(scontrol, ucontrol);
+
+	return false;
+}
+
+int snd_sof_volume_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo)
+{
+	struct soc_mixer_control *sm = (struct soc_mixer_control *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = sm->dobj.private;
+	unsigned int channels = scontrol->num_channels;
+	int platform_max;
+
+	if (!sm->platform_max)
+		sm->platform_max = sm->max;
+	platform_max = sm->platform_max;
+
+	if (platform_max == 1 && !strstr(kcontrol->id.name, " Volume"))
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_BOOLEAN;
+	else
+		uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
+
+	uinfo->count = channels;
+	uinfo->value.integer.min = 0;
+	uinfo->value.integer.max = platform_max - sm->min;
+	return 0;
+}
+
+int snd_sof_switch_get(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_mixer_control *sm = (struct soc_mixer_control *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = sm->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->switch_get)
+		return tplg_ops->control->switch_get(scontrol, ucontrol);
+
+	return 0;
+}
+
+int snd_sof_switch_put(struct snd_kcontrol *kcontrol,
+		       struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_mixer_control *sm = (struct soc_mixer_control *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = sm->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->switch_put)
+		return tplg_ops->control->switch_put(scontrol, ucontrol);
+
+	return false;
+}
+
+int snd_sof_enum_get(struct snd_kcontrol *kcontrol,
+		     struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_enum *se = (struct soc_enum *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = se->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->enum_get)
+		return tplg_ops->control->enum_get(scontrol, ucontrol);
+
+	return 0;
+}
+
+int snd_sof_enum_put(struct snd_kcontrol *kcontrol,
+		     struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_enum *se = (struct soc_enum *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = se->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->enum_put)
+		return tplg_ops->control->enum_put(scontrol, ucontrol);
+
+	return false;
+}
+
+int snd_sof_bytes_get(struct snd_kcontrol *kcontrol,
+		      struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_bytes_ext *be = (struct soc_bytes_ext *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = be->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->bytes_get)
+		return tplg_ops->control->bytes_get(scontrol, ucontrol);
+
+	return 0;
+}
+
+int snd_sof_bytes_put(struct snd_kcontrol *kcontrol,
+		      struct snd_ctl_elem_value *ucontrol)
+{
+	struct soc_bytes_ext *be = (struct soc_bytes_ext *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = be->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->bytes_put)
+		return tplg_ops->control->bytes_put(scontrol, ucontrol);
+
+	return 0;
+}
+
+int snd_sof_bytes_ext_put(struct snd_kcontrol *kcontrol,
+			  const unsigned int __user *binary_data,
+			  unsigned int size)
+{
+	struct soc_bytes_ext *be = (struct soc_bytes_ext *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = be->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	/* make sure we have at least a header */
+	if (size < sizeof(struct snd_ctl_tlv))
+		return -EINVAL;
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->bytes_ext_put)
+		return tplg_ops->control->bytes_ext_put(scontrol, binary_data, size);
+
+	return 0;
+}
+
+int snd_sof_bytes_ext_volatile_get(struct snd_kcontrol *kcontrol, unsigned int __user *binary_data,
+				   unsigned int size)
+{
+	struct soc_bytes_ext *be = (struct soc_bytes_ext *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = be->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+	int ret, err;
+
+	/* ignore the ext_volatile_get call if the callbacks are not provided */
+	if (!tplg_ops || !tplg_ops->control ||
+	    !tplg_ops->control->bytes_ext_volatile_get)
+		return 0;
+
+	ret = pm_runtime_resume_and_get(scomp->dev);
+	if (ret < 0 && ret != -EACCES) {
+		dev_err_ratelimited(scomp->dev, "%s: failed to resume %d\n", __func__, ret);
+		return ret;
+	}
+
+	/* Make sure the DSP/firmware is booted up */
+	ret = snd_sof_boot_dsp_firmware(sdev);
+	if (!ret)
+		ret = tplg_ops->control->bytes_ext_volatile_get(scontrol,
+								binary_data,
+								size);
+
+	err = pm_runtime_put_autosuspend(scomp->dev);
+	if (err < 0)
+		dev_err_ratelimited(scomp->dev, "%s: failed to idle %d\n", __func__, err);
+
+	return ret;
+}
+
+int snd_sof_bytes_ext_get(struct snd_kcontrol *kcontrol,
+			  unsigned int __user *binary_data,
+			  unsigned int size)
+{
+	struct soc_bytes_ext *be = (struct soc_bytes_ext *)kcontrol->private_value;
+	struct snd_sof_control *scontrol = be->dobj.private;
+	struct snd_soc_component *scomp = scontrol->scomp;
+	struct snd_sof_dev *sdev = snd_soc_component_get_drvdata(scomp);
+	const struct sof_ipc_tplg_ops *tplg_ops = sof_ipc_get_ops(sdev, tplg);
+
+	if (tplg_ops && tplg_ops->control && tplg_ops->control->bytes_ext_get)
+		return tplg_ops->control->bytes_ext_get(scontrol, binary_data, size);
+
+	return 0;
+}