From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug 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 Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- sound/soc/sof/sof-acpi-dev.c | 102 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 102 insertions(+) create mode 100644 sound/soc/sof/sof-acpi-dev.c (limited to 'sound/soc/sof/sof-acpi-dev.c') diff --git a/sound/soc/sof/sof-acpi-dev.c b/sound/soc/sof/sof-acpi-dev.c new file mode 100644 index 000000000..68bf1b570 --- /dev/null +++ b/sound/soc/sof/sof-acpi-dev.c @@ -0,0 +1,102 @@ +// 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 +// + +#include +#include +#include +#include +#include +#include +#include +#include "../intel/common/soc-intel-quirks.h" +#include "ops.h" +#include "sof-acpi-dev.h" + +/* platform specific devices */ +#include "intel/shim.h" + +static char *fw_path; +module_param(fw_path, charp, 0444); +MODULE_PARM_DESC(fw_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 int sof_acpi_debug; +module_param_named(sof_acpi_debug, sof_acpi_debug, int, 0444); +MODULE_PARM_DESC(sof_acpi_debug, "SOF ACPI debug options (0x0 all off)"); + +#define SOF_ACPI_DISABLE_PM_RUNTIME BIT(0) + +EXPORT_NS_DEV_PM_OPS(sof_acpi_pm, SND_SOC_SOF_ACPI_DEV) = { + 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_acpi_probe_complete(struct device *dev) +{ + dev_dbg(dev, "Completing SOF ACPI probe"); + + if (sof_acpi_debug & SOF_ACPI_DISABLE_PM_RUNTIME) + return; + + /* allow runtime_pm */ + pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS); + pm_runtime_use_autosuspend(dev); + pm_runtime_enable(dev); +} + +int sof_acpi_probe(struct platform_device *pdev, const struct sof_dev_desc *desc) +{ + struct device *dev = &pdev->dev; + struct snd_sof_pdata *sof_pdata; + + dev_dbg(dev, "ACPI DSP detected"); + + sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL); + if (!sof_pdata) + return -ENOMEM; + + if (!desc->ops) { + dev_err(dev, "error: no matching ACPI descriptor ops\n"); + return -ENODEV; + } + + sof_pdata->desc = desc; + sof_pdata->dev = &pdev->dev; + + sof_pdata->ipc_file_profile_base.ipc_type = desc->ipc_default; + sof_pdata->ipc_file_profile_base.fw_path = fw_path; + sof_pdata->ipc_file_profile_base.tplg_path = tplg_path; + + /* set callback to be called on successful device probe to enable runtime_pm */ + sof_pdata->sof_probe_complete = sof_acpi_probe_complete; + + /* call sof helper for DSP hardware probe */ + return snd_sof_device_probe(dev, sof_pdata); +} +EXPORT_SYMBOL_NS(sof_acpi_probe, "SND_SOC_SOF_ACPI_DEV"); + +void sof_acpi_remove(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + + if (!(sof_acpi_debug & SOF_ACPI_DISABLE_PM_RUNTIME)) + pm_runtime_disable(dev); + + /* call sof helper for DSP hardware remove */ + snd_sof_device_remove(dev); +} +EXPORT_SYMBOL_NS(sof_acpi_remove, "SND_SOC_SOF_ACPI_DEV"); + +MODULE_LICENSE("Dual BSD/GPL"); +MODULE_DESCRIPTION("SOF support for ACPI platforms"); -- cgit v1.3.1