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, 296 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-pci-dev.c b/sound/soc/sof/sof-pci-dev.c
new file mode 100644
index 000000000..c50249aad
--- /dev/null
+++ b/sound/soc/sof/sof-pci-dev.c
@@ -0,0 +1,296 @@
+// 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>
+//
+
+#include <linux/firmware.h>
+#include <linux/dmi.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_data/x86/soc.h>
+#include <linux/pm_runtime.h>
+#include <sound/soc-acpi.h>
+#include <sound/soc-acpi-intel-match.h>
+#include <sound/sof.h>
+#include "ops.h"
+#include "sof-pci-dev.h"
+
+static char *fw_path;
+module_param(fw_path, charp, 0444);
+MODULE_PARM_DESC(fw_path, "deprecated - moved to snd-sof module.");
+
+static char *fw_filename;
+module_param(fw_filename, charp, 0444);
+MODULE_PARM_DESC(fw_filename, "deprecated - moved to snd-sof module.");
+
+static char *lib_path;
+module_param(lib_path, charp, 0444);
+MODULE_PARM_DESC(lib_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_path;
+module_param(tplg_path, charp, 0444);
+MODULE_PARM_DESC(tplg_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_filename;
+module_param(tplg_filename, charp, 0444);
+MODULE_PARM_DESC(tplg_filename, "deprecated - moved to snd-sof module.");
+
+static int sof_pci_debug;
+module_param_named(sof_pci_debug, sof_pci_debug, int, 0444);
+MODULE_PARM_DESC(sof_pci_debug, "SOF PCI debug options (0x0 all off)");
+
+static int sof_pci_ipc_type = -1;
+module_param_named(ipc_type, sof_pci_ipc_type, int, 0444);
+MODULE_PARM_DESC(ipc_type, "deprecated - moved to snd-sof module.");
+
+static const char *sof_dmi_override_tplg_name;
+static bool sof_dmi_use_community_key;
+
+#define SOF_PCI_DISABLE_PM_RUNTIME BIT(0)
+
+static int sof_tplg_cb(const struct dmi_system_id *id)
+{
+	sof_dmi_override_tplg_name = id->driver_data;
+	return 1;
+}
+
+static const struct dmi_system_id sof_tplg_table[] = {
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Volteer"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98373_ALC5682I_I2S_UP4"),
+		},
+		.driver_data = "sof-tgl-rt5682-ssp0-max98373-ssp2.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Alder Lake Client Platform"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-ADL_MAX98373_ALC5682I_I2S"),
+		},
+		.driver_data = "sof-adl-rt5682-ssp0-max98373-ssp2.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98390_ALC5682I_I2S"),
+		},
+		.driver_data = "sof-adl-max98390-ssp2-rt5682-ssp0.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO_AMP-MAX98360_ALC5682VS_I2S_2WAY"),
+		},
+		.driver_data = "sof-adl-max98360a-rt5682-2way.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-AUDIO_MAX98357_ALC5682I_I2S_2WAY"),
+		},
+		.driver_data = "sof-adl-max98357a-rt5682-2way.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98360_ALC5682I_I2S_AMP_SSP2"),
+		},
+		.driver_data = "sof-adl-max98357a-rt5682.tplg",
+	},
+	{}
+};
+
+/* all Up boards use the community key */
+static int up_use_community_key(const struct dmi_system_id *id)
+{
+	sof_dmi_use_community_key = true;
+	return 1;
+}
+
+/*
+ * For ApolloLake Chromebooks we want to force the use of the Intel production key.
+ * All newer platforms use the community key
+ */
+static int chromebook_use_community_key(const struct dmi_system_id *id)
+{
+	if (!soc_intel_is_apl())
+		sof_dmi_use_community_key = true;
+	return 1;
+}
+
+static const struct dmi_system_id community_key_platforms[] = {
+	{
+		.ident = "Up boards",
+		.callback = up_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "AAEON"),
+		}
+	},
+	{
+		.ident = "Google Chromebooks",
+		.callback = chromebook_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google"),
+		}
+	},
+	{
+		.ident = "Google firmware",
+		.callback = chromebook_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_BIOS_VERSION, "Google"),
+		}
+	},
+	{},
+};
+
+EXPORT_NS_DEV_PM_OPS(sof_pci_pm, SND_SOC_SOF_PCI_DEV) = {
+	.prepare = snd_sof_prepare,
+	.complete = snd_sof_complete,
+	SYSTEM_SLEEP_PM_OPS(snd_sof_suspend, snd_sof_resume)
+	RUNTIME_PM_OPS(snd_sof_runtime_suspend, snd_sof_runtime_resume,
+		       snd_sof_runtime_idle)
+};
+
+static void sof_pci_probe_complete(struct device *dev)
+{
+	dev_dbg(dev, "Completing SOF PCI probe");
+
+	if (sof_pci_debug & SOF_PCI_DISABLE_PM_RUNTIME)
+		return;
+
+	/* allow runtime_pm */
+	pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+
+	/*
+	 * runtime pm for pci device is "forbidden" by default.
+	 * so call pm_runtime_allow() to enable it.
+	 */
+	pm_runtime_allow(dev);
+
+	/* mark last_busy for pm_runtime to make sure not suspend immediately */
+	pm_runtime_mark_last_busy(dev);
+
+	/* follow recommendation in pci-driver.c to decrement usage counter */
+	pm_runtime_put_noidle(dev);
+}
+
+int sof_pci_probe(struct pci_dev *pci, const struct pci_device_id *pci_id)
+{
+	struct sof_loadable_file_profile *path_override;
+	struct device *dev = &pci->dev;
+	const struct sof_dev_desc *desc =
+		(const struct sof_dev_desc *)pci_id->driver_data;
+	struct snd_sof_pdata *sof_pdata;
+	int ret;
+
+	dev_dbg(&pci->dev, "PCI DSP detected");
+
+	if (!desc) {
+		dev_err(dev, "error: no matching PCI descriptor\n");
+		return -ENODEV;
+	}
+
+	if (!desc->ops) {
+		dev_err(dev, "error: no matching PCI descriptor ops\n");
+		return -ENODEV;
+	}
+
+	sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL);
+	if (!sof_pdata)
+		return -ENOMEM;
+
+	ret = pcim_enable_device(pci);
+	if (ret < 0)
+		return ret;
+
+	ret = pcim_request_all_regions(pci, "Audio DSP");
+	if (ret < 0)
+		return ret;
+
+	sof_pdata->name = pci_name(pci);
+
+	/* PCI defines a vendor ID of 0xFFFF as invalid. */
+	if (pci->subsystem_vendor != 0xFFFF) {
+		sof_pdata->subsystem_vendor = pci->subsystem_vendor;
+		sof_pdata->subsystem_device = pci->subsystem_device;
+		sof_pdata->subsystem_id_set = true;
+	}
+
+	sof_pdata->desc = desc;
+	sof_pdata->dev = dev;
+
+	path_override = &sof_pdata->ipc_file_profile_base;
+
+	if (sof_pci_ipc_type < 0) {
+		path_override->ipc_type = desc->ipc_default;
+	} else if (sof_pci_ipc_type < SOF_IPC_TYPE_COUNT) {
+		path_override->ipc_type = sof_pci_ipc_type;
+	} else {
+		dev_err(dev, "Invalid IPC type requested: %d\n", sof_pci_ipc_type);
+		return -EINVAL;
+	}
+
+	path_override->fw_path = fw_path;
+	path_override->fw_name = fw_filename;
+	path_override->fw_lib_path = lib_path;
+	path_override->tplg_path = tplg_path;
+
+	if (dmi_check_system(community_key_platforms) &&
+	    sof_dmi_use_community_key) {
+		path_override->fw_path_postfix = "community";
+		path_override->fw_lib_path_postfix = "community";
+	}
+
+	/*
+	 * the topology filename will be provided in the machine descriptor, unless
+	 * it is overridden by a module parameter or DMI quirk.
+	 */
+	if (tplg_filename) {
+		path_override->tplg_name = tplg_filename;
+	} else {
+		dmi_check_system(sof_tplg_table);
+		if (sof_dmi_override_tplg_name)
+			path_override->tplg_name = sof_dmi_override_tplg_name;
+	}
+
+	/* set callback to be called on successful device probe to enable runtime_pm */
+	sof_pdata->sof_probe_complete = sof_pci_probe_complete;
+
+	/* call sof helper for DSP hardware probe */
+	return snd_sof_device_probe(dev, sof_pdata);
+}
+EXPORT_SYMBOL_NS(sof_pci_probe, "SND_SOC_SOF_PCI_DEV");
+
+void sof_pci_remove(struct pci_dev *pci)
+{
+	/* call sof helper for DSP hardware remove */
+	snd_sof_device_remove(&pci->dev);
+
+	/* follow recommendation in pci-driver.c to increment usage counter */
+	if (snd_sof_device_probe_completed(&pci->dev) &&
+	    !(sof_pci_debug & SOF_PCI_DISABLE_PM_RUNTIME))
+		pm_runtime_get_noresume(&pci->dev);
+}
+EXPORT_SYMBOL_NS(sof_pci_remove, "SND_SOC_SOF_PCI_DEV");
+
+void sof_pci_shutdown(struct pci_dev *pci)
+{
+	snd_sof_device_shutdown(&pci->dev);
+}
+EXPORT_SYMBOL_NS(sof_pci_shutdown, "SND_SOC_SOF_PCI_DEV");
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("SOF support for PCI platforms");