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, 179 insertions, 0 deletions

diff --git a/drivers/pinctrl/qcom/Kconfig b/drivers/pinctrl/qcom/Kconfig
new file mode 100644
index 000000000..18db35022
--- /dev/null
+++ b/drivers/pinctrl/qcom/Kconfig
@@ -0,0 +1,179 @@
+# SPDX-License-Identifier: GPL-2.0-only
+if (ARCH_QCOM || COMPILE_TEST)
+
+config PINCTRL_MSM
+	tristate "Qualcomm core pin controller driver"
+	depends on GPIOLIB
+	# OF for pinconf_generic_dt_node_to_map_group() from GENERIC_PINCONF
+	depends on OF
+	default ARCH_QCOM
+	select QCOM_SCM
+	select PINMUX
+	select GENERIC_PINMUX_FUNCTIONS
+	select PINCONF
+	select GENERIC_PINCONF
+	select GPIOLIB_IRQCHIP
+	select IRQ_DOMAIN_HIERARCHY
+	select IRQ_FASTEOI_HIERARCHY_HANDLERS
+
+source "drivers/pinctrl/qcom/Kconfig.msm"
+
+config PINCTRL_QCOM_SPMI_PMIC
+	tristate "Qualcomm SPMI PMIC pin controller driver"
+	depends on OF && SPMI
+	select REGMAP_SPMI
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select GPIOLIB_IRQCHIP
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	 This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	 Qualcomm GPIO and MPP blocks found in the Qualcomm PMIC's chips,
+	 which are using SPMI for communication with SoC. Example PMIC's
+	 devices are pm8841, pm8941 and pma8084.
+
+config PINCTRL_QCOM_SSBI_PMIC
+	tristate "Qualcomm SSBI PMIC pin controller driver"
+	depends on OF
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select GPIOLIB
+	select GPIOLIB_IRQCHIP
+	select IRQ_DOMAIN_HIERARCHY
+	help
+	 This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	 Qualcomm GPIO and MPP blocks found in the Qualcomm PMIC's chips,
+	 which are using SSBI for communication with SoC. Example PMIC's
+	 devices are pm8058 and pm8921.
+
+config PINCTRL_LPASS_LPI
+	tristate "Qualcomm LPASS LPI pin controller driver"
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select GENERIC_PINCTRL_GROUPS
+	depends on PM_CLK
+	depends on GPIOLIB
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SoCs.
+
+config PINCTRL_MILOS_LPASS_LPI
+	tristate "Qualcomm Milos LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc Milos
+	  platform.
+
+config PINCTRL_SC7280_LPASS_LPI
+	tristate "Qualcomm SC7280 and SM8350 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SC7280
+	  and SM8350 platforms.
+
+config PINCTRL_SDM660_LPASS_LPI
+	tristate "Qualcomm SDM660 LPASS LPI pin controller driver"
+	depends on GPIOLIB
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SDM660 platform.
+
+config PINCTRL_SM4250_LPASS_LPI
+	tristate "Qualcomm SM4250 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM4250 platform.
+
+config PINCTRL_SDM670_LPASS_LPI
+	tristate "Qualcomm SDM670 LPASS LPI pin controller driver"
+	depends on GPIOLIB
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SDM670 platform.
+
+config PINCTRL_SM6115_LPASS_LPI
+	tristate "Qualcomm SM6115 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM6115 platform.
+
+config PINCTRL_SM6350_LPASS_LPI
+	tristate "Qualcomm SM6350 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM6350 platform.
+
+config PINCTRL_SM8250_LPASS_LPI
+	tristate "Qualcomm SM8250 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM8250 platform.
+
+config PINCTRL_SM8450_LPASS_LPI
+	tristate "Qualcomm SM8450 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM8450 platform.
+
+config PINCTRL_SC8280XP_LPASS_LPI
+	tristate "Qualcomm SC8280XP LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SC8280XP platform.
+
+config PINCTRL_SM8550_LPASS_LPI
+	tristate "Qualcomm SM8550 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM8550
+	  platform.
+
+config PINCTRL_SM8650_LPASS_LPI
+	tristate "Qualcomm SM8650 LPASS LPI pin controller driver"
+	depends on ARM64 || COMPILE_TEST
+	depends on PINCTRL_LPASS_LPI
+	help
+	  This is the pinctrl, pinmux, pinconf and gpiolib driver for the
+	  Qualcomm Technologies Inc LPASS (Low Power Audio SubSystem) LPI
+	  (Low Power Island) found on the Qualcomm Technologies Inc SM8650
+	  platform.
+
+endif