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, 244 insertions, 0 deletions

diff --git a/drivers/phy/qualcomm/Kconfig b/drivers/phy/qualcomm/Kconfig
new file mode 100644
index 000000000..d910a5d1a
--- /dev/null
+++ b/drivers/phy/qualcomm/Kconfig
@@ -0,0 +1,244 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Phy drivers for Qualcomm and Atheros platforms
+#
+config PHY_ATH79_USB
+	tristate "Atheros AR71XX/9XXX USB PHY driver"
+	depends on OF && (ATH79 || COMPILE_TEST)
+	default y if USB_EHCI_HCD_PLATFORM || USB_OHCI_HCD_PLATFORM
+	select RESET_CONTROLLER
+	select GENERIC_PHY
+	help
+	  Enable this to support the USB PHY on Atheros AR71XX/9XXX SoCs.
+
+config PHY_QCOM_APQ8064_SATA
+	tristate "Qualcomm APQ8064 SATA SerDes/PHY driver"
+	depends on ARCH_QCOM
+	depends on HAS_IOMEM
+	depends on OF
+	select GENERIC_PHY
+
+config PHY_QCOM_EDP
+	tristate "Qualcomm eDP PHY driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on OF
+	depends on COMMON_CLK
+	select GENERIC_PHY
+	help
+	  Enable this driver to support the Qualcomm eDP PHY found in various
+	  Qualcomm chipsets.
+
+config PHY_QCOM_IPQ4019_USB
+	tristate "Qualcomm IPQ4019 USB PHY driver"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Support for the USB PHY-s on Qualcomm IPQ40xx SoC-s.
+
+config PHY_QCOM_IPQ806X_SATA
+	tristate "Qualcomm IPQ806x SATA SerDes/PHY driver"
+	depends on ARCH_QCOM
+	depends on HAS_IOMEM
+	depends on OF
+	select GENERIC_PHY
+
+config PHY_QCOM_PCIE2
+	tristate "Qualcomm PCIe Gen2 PHY Driver"
+	depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable this to support the Qualcomm PCIe PHY, used with the Synopsys
+	  based PCIe controller.
+
+menuconfig PHY_QCOM_QMP
+	tristate "Qualcomm QMP PHY Drivers"
+	depends on OF && COMMON_CLK && (ARCH_QCOM || COMPILE_TEST)
+
+if PHY_QCOM_QMP
+
+config PHY_QCOM_QMP_COMBO
+	tristate "Qualcomm QMP Combo PHY Driver"
+	default PHY_QCOM_QMP
+	depends on TYPEC || TYPEC=n
+	depends on DRM || DRM=n
+	select GENERIC_PHY
+	select MFD_SYSCON
+	select DRM_AUX_BRIDGE if DRM_BRIDGE
+	help
+	  Enable this to support the QMP Combo PHY transceiver that is used
+	  with USB3 and DisplayPort controllers on Qualcomm chips.
+
+config PHY_QCOM_QMP_PCIE
+	tristate "Qualcomm QMP PCIe PHY Driver"
+	depends on PCI || COMPILE_TEST
+	select GENERIC_PHY
+	default PHY_QCOM_QMP
+	help
+	  Enable this to support the QMP PCIe PHY transceiver that is used
+	  with PCIe controllers on Qualcomm chips.
+
+config PHY_QCOM_QMP_PCIE_MULTIPHY
+	tristate "Qualcomm QMP PCIe Multi PHY Driver"
+	depends on PCI || COMPILE_TEST
+	select GENERIC_PHY
+	help
+	  Enable this to support the QMP PCIe PHY transceiver that is used
+	  with PCIe controllers on Qualcomm chips. This PHY is a single
+	  multi-lane QMP block that can be configured either as one wide
+	  link or as multiple narrower independent links (bifurcation).
+
+config PHY_QCOM_QMP_PCIE_8996
+	tristate "Qualcomm QMP PCIe 8996 PHY Driver"
+	depends on PCI || COMPILE_TEST
+	select GENERIC_PHY
+	default PHY_QCOM_QMP
+	help
+	  Enable this to support the QMP PCIe PHY transceiver that is used
+	  with PCIe controllers on Qualcomm msm8996 chips.
+
+config PHY_QCOM_QMP_UFS
+	tristate "Qualcomm QMP UFS PHY Driver"
+	select GENERIC_PHY
+	default PHY_QCOM_QMP
+	help
+	  Enable this to support the QMP UFS PHY transceiver that is used
+	  with UFS controllers on Qualcomm chips.
+
+config PHY_QCOM_QMP_USB
+	tristate "Qualcomm QMP USB PHY Driver"
+	select GENERIC_PHY
+	default PHY_QCOM_QMP
+	help
+	  Enable this to support the QMP USB PHY transceiver that is used
+	  with USB3 controllers on Qualcomm chips.
+
+config PHY_QCOM_QMP_USB_LEGACY
+	tristate "Qualcomm QMP legacy USB PHY Driver"
+	select GENERIC_PHY
+	default n
+	help
+	  Enable this legacy driver to support the QMP USB+DisplayPort Combo
+	  PHY transceivers working only in USB3 mode on Qualcomm chips. This
+	  driver exists only for compatibility with older device trees,
+	  existing users have been migrated to PHY_QCOM_QMP_COMBO driver.
+
+endif # PHY_QCOM_QMP
+
+config PHY_QCOM_QUSB2
+	tristate "Qualcomm QUSB2 PHY Driver"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	depends on NVMEM || !NVMEM
+	select GENERIC_PHY
+	help
+	  Enable this to support the HighSpeed QUSB2 PHY transceiver for USB
+	  controllers on Qualcomm chips. This driver supports the high-speed
+	  PHY which is usually paired with either the ChipIdea or Synopsys DWC3
+	  USB IPs on MSM SOCs.
+
+config PHY_QCOM_EUSB2_REPEATER
+	tristate "Qualcomm PMIC eUSB2 Repeater Driver"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable support for the USB high-speed eUSB2 repeater on Qualcomm
+	  PMICs. The repeater is paired with a Synopsys or M31 eUSB2 Phy
+	  on Qualcomm SOCs.
+
+config PHY_QCOM_M31_USB
+	tristate "Qualcomm M31 HS PHY driver support"
+	depends on USB && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable this to support M31 HS PHY transceivers on Qualcomm chips
+	  with DWC3 USB core. It handles PHY initialization, clock
+	  management required after resetting the hardware and power
+	  management. This driver is required even for peripheral only or
+	  host only mode configurations.
+
+config PHY_QCOM_UNIPHY_PCIE_28LP
+	bool "PCIE UNIPHY 28LP PHY driver"
+	depends on ARCH_QCOM
+	depends on COMMON_CLK
+	depends on HAS_IOMEM
+	depends on OF
+	select GENERIC_PHY
+	help
+	  Enable this to support the PCIe UNIPHY 28LP phy transceiver that
+	  is used with PCIe controllers on Qualcomm IPQ5332 chips. It
+	  handles PHY initialization, clock management required after
+	  resetting the hardware and power management.
+
+config PHY_QCOM_M31_EUSB
+	tristate "Qualcomm M31 eUSB2 PHY driver support"
+	depends on USB && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable this to support M31 EUSB2 PHY transceivers on Qualcomm
+	  chips with DWC3 USB core. It supports initializing and cleaning
+	  up of the associated USB repeater that is paired with the eUSB2
+	  PHY.
+
+config PHY_QCOM_USB_HS
+	tristate "Qualcomm USB HS PHY module"
+	depends on USB_ULPI_BUS
+	depends on EXTCON || !EXTCON # if EXTCON=m, this cannot be built-in
+	select GENERIC_PHY
+	help
+	  Support for the USB high-speed ULPI compliant phy on Qualcomm
+	  chipsets.
+
+config PHY_QCOM_USB_SNPS_FEMTO_V2
+	tristate "Qualcomm SNPS FEMTO USB HS PHY V2 module"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  Enable support for the USB high-speed SNPS Femto phy on Qualcomm
+	  chipsets.  This PHY has differences in the register map compared
+	  to the V1 variants.  The PHY is paired with a Synopsys DWC3 USB
+	  controller on Qualcomm SOCs.
+
+config PHY_QCOM_USB_HSIC
+	tristate "Qualcomm USB HSIC ULPI PHY module"
+	depends on USB_ULPI_BUS
+	select GENERIC_PHY
+	help
+	  Support for the USB HSIC ULPI compliant PHY on QCOM chipsets.
+
+config PHY_QCOM_USB_HS_28NM
+	tristate "Qualcomm 28nm High-Speed PHY"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	depends on EXTCON || !EXTCON # if EXTCON=m, this cannot be built-in
+	select GENERIC_PHY
+	help
+	  Enable this to support the Qualcomm Synopsys DesignWare Core 28nm
+	  High-Speed PHY driver. This driver supports the Hi-Speed PHY which
+	  is usually paired with either the ChipIdea or Synopsys DWC3 USB
+	  IPs on MSM SOCs.
+
+config PHY_QCOM_USB_SS
+	tristate "Qualcomm USB Super-Speed PHY driver"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	depends on EXTCON || !EXTCON # if EXTCON=m, this cannot be built-in
+	select GENERIC_PHY
+	help
+	  Enable this to support the Super-Speed USB transceiver on various
+	  Qualcomm chipsets.
+
+config PHY_QCOM_IPQ806X_USB
+	tristate "Qualcomm IPQ806x DWC3 USB PHY driver"
+	depends on HAS_IOMEM
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	select GENERIC_PHY
+	help
+	  This option enables support for the Synopsis PHYs present inside the
+	  Qualcomm USB3.0 DWC3 controller on ipq806x SoC. This driver supports
+	  both HS and SS PHY controllers.
+
+config PHY_QCOM_SGMII_ETH
+	tristate "Qualcomm DWMAC SGMII SerDes/PHY driver"
+	depends on OF && (ARCH_QCOM || COMPILE_TEST)
+	depends on HAS_IOMEM
+	select GENERIC_PHY
+	help
+	  Enable this to support the internal SerDes/SGMII PHY on various
+	  Qualcomm chipsets.