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, 104 insertions, 0 deletions

diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
new file mode 100644
index 000000000..2bbfb9ff1
--- /dev/null
+++ b/drivers/nvmem/Makefile
@@ -0,0 +1,104 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for nvmem drivers.
+#
+
+obj-$(CONFIG_NVMEM)		+= nvmem_core.o
+nvmem_core-y			:= core.o
+obj-$(CONFIG_NVMEM_LAYOUTS)	+= nvmem_layouts.o
+nvmem_layouts-y			:= layouts.o
+obj-y				+= layouts/
+
+# Devices
+obj-$(CONFIG_EEPROM_AT24)		+= at24.o
+obj-$(CONFIG_EEPROM_AT25)		+= at25.o
+obj-$(CONFIG_EEPROM_93XX46)		+= eeprom_93xx46.o
+obj-$(CONFIG_EEPROM_EE1004)		+= ee1004.o
+obj-$(CONFIG_EEPROM_M24LR)		+= m24lr.o
+obj-$(CONFIG_NVMEM_AIROHA_SMC_EFUSES)	+= nvmem-airoha-smc-efuses.o
+nvmem-airoha-smc-efuses-y 		:= airoha-smc-efuses.o
+obj-$(CONFIG_NVMEM_AN8855_EFUSE)	+= nvmem-an8855-efuse.o
+nvmem-an8855-efuse-y 			:= an8855-efuse.o
+obj-$(CONFIG_NVMEM_APPLE_EFUSES)	+= nvmem-apple-efuses.o
+nvmem-apple-efuses-y 			:= apple-efuses.o
+obj-$(CONFIG_NVMEM_APPLE_SPMI)		+= apple_nvmem_spmi.o
+apple_nvmem_spmi-y			:= apple-spmi-nvmem.o
+obj-$(CONFIG_NVMEM_BCM_OCOTP)		+= nvmem-bcm-ocotp.o
+nvmem-bcm-ocotp-y			:= bcm-ocotp.o
+obj-$(CONFIG_NVMEM_BRCM_NVRAM)		+= nvmem_brcm_nvram.o
+nvmem_brcm_nvram-y			:= brcm_nvram.o
+obj-$(CONFIG_NVMEM_IMX_IIM)		+= nvmem-imx-iim.o
+nvmem-imx-iim-y				:= imx-iim.o
+obj-$(CONFIG_NVMEM_IMX_OCOTP)		+= nvmem-imx-ocotp.o
+nvmem-imx-ocotp-y			:= imx-ocotp.o
+obj-$(CONFIG_NVMEM_IMX_OCOTP_ELE)	+= nvmem-imx-ocotp-ele.o
+nvmem-imx-ocotp-ele-y			:= imx-ocotp-ele.o
+obj-$(CONFIG_NVMEM_IMX_OCOTP_SCU)	+= nvmem-imx-ocotp-scu.o
+nvmem-imx-ocotp-scu-y			:= imx-ocotp-scu.o
+obj-$(CONFIG_NVMEM_JZ4780_EFUSE)	+= nvmem_jz4780_efuse.o
+nvmem_jz4780_efuse-y			:= jz4780-efuse.o
+obj-$(CONFIG_NVMEM_LAN9662_OTPC)	+= nvmem-lan9662-otpc.o
+nvmem-lan9662-otpc-y		:= lan9662-otpc.o
+obj-$(CONFIG_NVMEM_LAYERSCAPE_SFP)	+= nvmem-layerscape-sfp.o
+nvmem-layerscape-sfp-y			:= layerscape-sfp.o
+obj-$(CONFIG_NVMEM_LPC18XX_EEPROM)	+= nvmem_lpc18xx_eeprom.o
+nvmem_lpc18xx_eeprom-y			:= lpc18xx_eeprom.o
+obj-$(CONFIG_NVMEM_LPC18XX_OTP)		+= nvmem_lpc18xx_otp.o
+nvmem_lpc18xx_otp-y			:= lpc18xx_otp.o
+obj-$(CONFIG_NVMEM_MAX77759)		+= nvmem-max77759.o
+nvmem-max77759-y			:= max77759-nvmem.o
+obj-$(CONFIG_NVMEM_MESON_EFUSE)		+= nvmem_meson_efuse.o
+nvmem_meson_efuse-y			:= meson-efuse.o
+obj-$(CONFIG_NVMEM_MESON_MX_EFUSE)	+= nvmem_meson_mx_efuse.o
+nvmem_meson_mx_efuse-y			:= meson-mx-efuse.o
+obj-$(CONFIG_NVMEM_MICROCHIP_OTPC)	+= nvmem-microchip-otpc.o
+nvmem-microchip-otpc-y			:= microchip-otpc.o
+obj-$(CONFIG_NVMEM_MTK_EFUSE)		+= nvmem_mtk-efuse.o
+nvmem_mtk-efuse-y			:= mtk-efuse.o
+obj-$(CONFIG_NVMEM_MXS_OCOTP)		+= nvmem-mxs-ocotp.o
+nvmem-mxs-ocotp-y			:= mxs-ocotp.o
+obj-$(CONFIG_NVMEM_NINTENDO_OTP)	+= nvmem-nintendo-otp.o
+nvmem-nintendo-otp-y			:= nintendo-otp.o
+obj-$(CONFIG_NVMEM_QCOM_QFPROM)		+= nvmem_qfprom.o
+nvmem_qfprom-y				:= qfprom.o
+obj-$(CONFIG_NVMEM_QCOM_SEC_QFPROM)	+= nvmem_sec_qfprom.o
+nvmem_sec_qfprom-y			:= sec-qfprom.o
+obj-$(CONFIG_NVMEM_QNAP_MCU_EEPROM)	+= nvmem-qnap-mcu-eeprom.o
+nvmem-qnap-mcu-eeprom-y			:= qnap-mcu-eeprom.o
+obj-$(CONFIG_NVMEM_RAVE_SP_EEPROM)	+= nvmem-rave-sp-eeprom.o
+nvmem-rave-sp-eeprom-y			:= rave-sp-eeprom.o
+obj-$(CONFIG_NVMEM_RCAR_EFUSE)		+= nvmem-rcar-efuse.o
+nvmem-rcar-efuse-y			:= rcar-efuse.o
+obj-$(CONFIG_NVMEM_RMEM) 		+= nvmem-rmem.o
+nvmem-rmem-y				:= rmem.o
+obj-$(CONFIG_NVMEM_ROCKCHIP_EFUSE)	+= nvmem_rockchip_efuse.o
+nvmem_rockchip_efuse-y			:= rockchip-efuse.o
+obj-$(CONFIG_NVMEM_ROCKCHIP_OTP)	+= nvmem-rockchip-otp.o
+nvmem-rockchip-otp-y			:= rockchip-otp.o
+obj-$(CONFIG_NVMEM_SC27XX_EFUSE)	+= nvmem-sc27xx-efuse.o
+nvmem-sc27xx-efuse-y			:= sc27xx-efuse.o
+obj-$(CONFIG_NVMEM_SNVS_LPGPR)		+= nvmem_snvs_lpgpr.o
+nvmem_snvs_lpgpr-y			:= snvs_lpgpr.o
+obj-$(CONFIG_NVMEM_SPMI_SDAM)		+= nvmem_qcom-spmi-sdam.o
+nvmem_qcom-spmi-sdam-y			+= qcom-spmi-sdam.o
+obj-$(CONFIG_NVMEM_SPRD_EFUSE)		+= nvmem_sprd_efuse.o
+nvmem_sprd_efuse-y			:= sprd-efuse.o
+obj-$(CONFIG_NVMEM_STM32_ROMEM)		+= nvmem_stm32_romem.o
+nvmem_stm32_romem-y 			:= stm32-romem.o
+nvmem_stm32_romem-$(CONFIG_NVMEM_STM32_BSEC_OPTEE_TA) += stm32-bsec-optee-ta.o
+obj-$(CONFIG_NVMEM_SUNPLUS_OCOTP)	+= nvmem_sunplus_ocotp.o
+nvmem_sunplus_ocotp-y			:= sunplus-ocotp.o
+obj-$(CONFIG_NVMEM_SUNXI_SID)		+= nvmem_sunxi_sid.o
+nvmem_sunxi_sid-y			:= sunxi_sid.o
+obj-$(CONFIG_NVMEM_S32G_OCOTP)		+= nvmem-s32g-ocotp-nvmem.o
+nvmem-s32g-ocotp-nvmem-y		:= s32g-ocotp-nvmem.o
+obj-$(CONFIG_NVMEM_U_BOOT_ENV)		+= nvmem_u-boot-env.o
+nvmem_u-boot-env-y			:= u-boot-env.o
+obj-$(CONFIG_NVMEM_UNIPHIER_EFUSE)	+= nvmem-uniphier-efuse.o
+nvmem-uniphier-efuse-y			:= uniphier-efuse.o
+obj-$(CONFIG_NVMEM_VF610_OCOTP)		+= nvmem-vf610-ocotp.o
+nvmem-vf610-ocotp-y			:= vf610-ocotp.o
+obj-$(CONFIG_NVMEM_ZYNQMP)		+= nvmem_zynqmp_nvmem.o
+nvmem_zynqmp_nvmem-y			:= zynqmp_nvmem.o
+obj-$(CONFIG_NVMEM_QORIQ_EFUSE)		+= nvmem-qoriq-efuse.o
+nvmem-qoriq-efuse-y			:= qoriq-efuse.o