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, 306 insertions, 0 deletions

diff --git a/sound/soc/sof/Kconfig b/sound/soc/sof/Kconfig
new file mode 100644
index 000000000..a487ab0b5
--- /dev/null
+++ b/sound/soc/sof/Kconfig
@@ -0,0 +1,306 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menuconfig SND_SOC_SOF_TOPLEVEL
+	bool "Sound Open Firmware (SOF) platforms"
+	help
+	  This adds support for Sound Open Firmware (SOF). SOF is free and
+	  generic open source audio DSP firmware for multiple devices.
+	  Say Y if you have such a device that is supported by SOF.
+	  If unsure select "N".
+
+if SND_SOC_SOF_TOPLEVEL
+
+config SND_SOC_SOF_PCI_DEV
+	tristate
+
+config SND_SOC_SOF_PCI
+	tristate "SOF PCI enumeration support"
+	depends on PCI
+	help
+	  This adds support for PCI enumeration. This option is
+	  required to enable Intel Skylake+ devices.
+	  For backwards-compatibility with previous configurations the selection will
+	  be used as default for platform-specific drivers.
+	  Say Y if you need this option.
+	  If unsure select "N".
+
+config SND_SOC_SOF_ACPI
+	tristate "SOF ACPI enumeration support"
+	depends on ACPI || COMPILE_TEST
+	help
+	  This adds support for ACPI enumeration. This option is required
+	  to enable Intel Broadwell/Baytrail/Cherrytrail devices.
+	  For backwards-compatibility with previous configurations the selection will
+	  be used as default for platform-specific drivers.
+	  Say Y if you need this option.
+	  If unsure select "N".
+
+config SND_SOC_SOF_ACPI_DEV
+	tristate
+
+config SND_SOC_SOF_OF
+	tristate "SOF OF enumeration support"
+	depends on OF
+	help
+	  This adds support for Device Tree enumeration. This option is
+	  required to enable i.MX8 or Mediatek devices.
+	  Say Y if you need this option. If unsure select "N".
+
+config SND_SOC_SOF_OF_DEV
+	tristate
+
+config SND_SOC_SOF_COMPRESS
+	bool
+	select SND_SOC_COMPRESS
+
+config SND_SOC_SOF_DEBUG_PROBES
+	tristate
+	select SND_SOC_SOF_CLIENT
+	select SND_SOC_COMPRESS
+	help
+	  This option enables the data probing feature that can be used to
+	  gather data directly from specific points of the audio pipeline.
+	  This option is not user-selectable but automagically handled by
+	  'select' statements at a higher level.
+
+config SND_SOC_SOF_CLIENT
+	tristate
+	select AUXILIARY_BUS
+	help
+	  This option is not user-selectable but automagically handled by
+	  'select' statements at a higher level.
+
+config SND_SOC_SOF_DEVELOPER_SUPPORT
+	bool "SOF developer options support"
+	depends on EXPERT && SND_SOC_SOF
+	help
+	  This option unlocks SOF developer options for debug/performance/
+	  code hardening.
+	  Distributions should not select this option, only SOF development
+	  teams should select it.
+	  Say Y if you are involved in SOF development and need this option.
+	  If not, select N.
+
+if SND_SOC_SOF_DEVELOPER_SUPPORT
+
+config SND_SOC_SOF_FORCE_PROBE_WORKQUEUE
+	bool "SOF force probe workqueue"
+	select SND_SOC_SOF_PROBE_WORK_QUEUE
+	help
+	  This option forces the use of a probe workqueue, which is only used
+	  when HDaudio is enabled due to module dependencies. Forcing this
+	  option is intended for debug only, but this should not add any
+	  functional issues in nominal cases.
+	  Say Y if you are involved in SOF development and need this option.
+	  If not, select N.
+
+config SND_SOC_SOF_NOCODEC
+	tristate
+
+config SND_SOC_SOF_NOCODEC_SUPPORT
+	bool "SOF nocodec static mode support"
+	help
+	  This adds support for a dummy/nocodec machine driver fallback
+	  option if no known codec is detected. This is typically only
+	  enabled for developers or devices where the sound card is
+	  controlled externally.
+	  This option is mutually exclusive at build time with the Intel HDAudio support.
+	  Selecting it may have negative impacts and prevent e.g. microphone
+	  functionality from being enabled on Intel CoffeeLake and later
+	  platforms.
+	  Distributions should not select this option!
+	  Say Y if you need this nocodec fallback option.
+	  If unsure select "N".
+
+config SND_SOC_SOF_STRICT_ABI_CHECKS
+	bool "SOF strict ABI checks"
+	help
+	  This option enables strict ABI checks for firmware and topology
+	  files.
+	  When these files are more recent than the kernel, the kernel
+	  will handle the functionality it supports and may report errors
+	  during topology creation or run-time usage if new functionality
+	  is invoked.
+	  This option will stop topology creation and firmware load upfront.
+	  It is intended for SOF CI/releases and not for users or distros.
+	  Say Y if you want strict ABI checks for an SOF release.
+	  If you are not involved in SOF releases and CI development,
+	  select "N".
+
+config SND_SOC_SOF_ALLOW_FALLBACK_TO_NEWER_IPC_VERSION
+	bool "SOF allow fallback to newer IPC version"
+	help
+	  This option will allow the kernel to try to 'fallback' to a newer IPC
+	  version if there are missing firmware files to satisfy the default IPC
+	  version.
+	  IPC version fallback to older versions is not affected by this option,
+	  it is always available.
+	  Say Y if you are involved in SOF development and need this option.
+	  If not, select N.
+
+config SND_SOC_SOF_DEBUG
+	bool "SOF debugging features"
+	help
+	  This option can be used to enable or disable individual SOF firmware
+	  and driver debugging options.
+	  Say Y if you are debugging SOF FW or drivers.
+	  If unsure select "N".
+
+if SND_SOC_SOF_DEBUG
+
+config SND_SOC_SOF_NOCODEC_DEBUG_SUPPORT
+	bool "SOF nocodec debug mode support"
+	depends on !SND_SOC_SOF_NOCODEC_SUPPORT
+	help
+	  This adds support for a dummy/nocodec machine driver fallback
+	  option.
+	  Unlike the SND_SOC_SOF_NOCODEC_SUPPORT, this option is NOT
+	  mutually exclusive at build with the Intel HDAudio support. The
+	  selection will be done depending on command line or modprobe.d settings
+	  Distributions should not select this option!
+	  Say Y if you need this nocodec debug fallback option.
+	  If unsure select "N".
+
+config SND_SOC_SOF_FORCE_NOCODEC_MODE
+	bool "SOF force nocodec Mode"
+	depends on SND_SOC_SOF_NOCODEC_SUPPORT
+	help
+	  This forces SOF to use dummy/nocodec as machine driver, even
+	  though there is a codec detected on the real platform. This is
+	  typically only enabled for developers for debug purposes, before
+	  codec/machine driver is ready, or to exclude the impact of those
+	  drivers.
+	  Say Y if you need this force nocodec mode option.
+	  If unsure select "N".
+
+config SND_SOC_SOF_DEBUG_XRUN_STOP
+	bool "SOF stop on XRUN"
+	help
+	  This option forces PCMs to stop on any XRUN event. This is useful to
+	  preserve any trace data and pipeline status prior to the XRUN.
+	  Say Y if you are debugging SOF FW pipeline XRUNs.
+	  If unsure select "N".
+
+config SND_SOC_SOF_DEBUG_VERBOSE_IPC
+	bool "SOF verbose IPC logs"
+	help
+	  This option enables more verbose IPC logs, with command types in
+	  human-readable form instead of just 32-bit hex dumps. This is useful
+	  if you are trying to debug IPC with the DSP firmware.
+	  If unsure select "N".
+
+config SND_SOC_SOF_DEBUG_FORCE_IPC_POSITION
+	bool "SOF force to use IPC for position update on SKL+"
+	help
+	  This option forces to handle stream position update IPCs and run PCM
+	  elapse to inform ALSA about that, on platforms (e.g. Intel SKL+) that
+	  with other approach (e.g. HDAC DPIB/posbuf) to elapse PCM.
+	  On platforms (e.g. Intel SKL-) where position update IPC is the only
+	  one choice, this setting won't impact anything.
+	  If you are trying to debug pointer update with position IPCs or where
+	  DPIB/posbuf is not ready, select "Y".
+	  If unsure select "N".
+
+config SND_SOC_SOF_DEBUG_ENABLE_DEBUGFS_CACHE
+	bool "SOF enable debugfs caching"
+	help
+	  This option enables caching of debugfs
+	  memory -> DSP resource (memory, register, etc)
+	  before the audio DSP is suspended. This will increase the suspend
+	  latency and therefore should be used for debug purposes only.
+	  Say Y if you want to enable caching the memory windows.
+	  If unsure, select "N".
+
+config SND_SOC_SOF_DEBUG_ENABLE_FIRMWARE_TRACE
+	bool "SOF enable firmware trace"
+	help
+	  The firmware trace can be enabled either at build-time with
+	  this option, or dynamically by setting flags in the SOF core
+	  module parameter (similar to dynamic debug).
+	  If unsure, select "N".
+
+config SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST
+	tristate "SOF enable IPC flood test"
+	depends on SND_SOC_SOF
+	select SND_SOC_SOF_CLIENT
+	help
+	  This option enables a separate client device for IPC flood test
+	  which can be used to flood the DSP with test IPCs and gather stats
+	  about response times.
+	  Say Y if you want to enable IPC flood test.
+	  If unsure, select "N".
+
+config SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST_NUM
+	int "Number of IPC flood test clients"
+	range 1 32
+	default 2
+	depends on SND_SOC_SOF_DEBUG_IPC_FLOOD_TEST
+	help
+	  Select the number of IPC flood test clients to be created.
+
+config SND_SOC_SOF_DEBUG_IPC_MSG_INJECTOR
+	tristate "SOF enable IPC message injector"
+	depends on SND_SOC_SOF
+	select SND_SOC_SOF_CLIENT
+	help
+	  This option enables the IPC message injector which can be used to send
+	  crafted IPC messages to the DSP to test its robustness.
+	  Say Y if you want to enable the IPC message injector.
+	  If unsure, select "N".
+
+config SND_SOC_SOF_DEBUG_IPC_KERNEL_INJECTOR
+	tristate "SOF enable IPC kernel injector"
+	depends on SND_SOC_SOF
+	select SND_SOC_SOF_CLIENT
+	help
+	  This option enables the IPC kernel injector which can be used to send
+	  crafted IPC messages to the kernel to test its robustness against
+	  DSP messages.
+	  Say Y if you want to enable the IPC kernel injector.
+	  If unsure, select "N".
+
+config SND_SOC_SOF_DEBUG_RETAIN_DSP_CONTEXT
+	bool "SOF retain DSP context on any FW exceptions"
+	help
+	  This option keeps the DSP in D0 state so that firmware debug
+	  information can be retained and dumped to userspace.
+	  Say Y if you want to retain DSP context for FW exceptions.
+	  If unsure, select "N".
+
+endif ## SND_SOC_SOF_DEBUG
+
+endif ## SND_SOC_SOF_DEVELOPER_SUPPORT
+
+config SND_SOC_SOF
+	tristate
+	select SND_SOC_TOPOLOGY
+	select SND_SOC_SOF_NOCODEC if SND_SOC_SOF_NOCODEC_SUPPORT
+	select SND_SOC_SOF_NOCODEC if SND_SOC_SOF_NOCODEC_DEBUG_SUPPORT
+	help
+	  This option is not user-selectable but automagically handled by
+	  'select' statements at a higher level.
+	  The selection is made at the top level and does not exactly follow
+	  module dependencies but since the module or built-in type is decided
+	  at the top level it doesn't matter.
+
+config SND_SOC_SOF_PROBE_WORK_QUEUE
+	bool
+	help
+	  This option is not user-selectable but automagically handled by
+	  'select' statements at a higher level.
+	  When selected, the probe is handled in two steps, for example to
+	  avoid lockdeps if request_module is used in the probe.
+
+# Supported IPC versions
+config SND_SOC_SOF_IPC3
+	bool
+
+config SND_SOC_SOF_IPC4
+	bool
+
+source "sound/soc/sof/amd/Kconfig"
+source "sound/soc/sof/imx/Kconfig"
+source "sound/soc/sof/intel/Kconfig"
+source "sound/soc/sof/mediatek/Kconfig"
+source "sound/soc/sof/xtensa/Kconfig"
+
+endif