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, 28 insertions, 0 deletions

diff --git a/drivers/phy/qualcomm/Makefile b/drivers/phy/qualcomm/Makefile
new file mode 100644
index 000000000..8bf887d58
--- /dev/null
+++ b/drivers/phy/qualcomm/Makefile
@@ -0,0 +1,28 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_PHY_ATH79_USB)		+= phy-ath79-usb.o
+obj-$(CONFIG_PHY_QCOM_APQ8064_SATA)	+= phy-qcom-apq8064-sata.o
+obj-$(CONFIG_PHY_QCOM_EDP)		+= phy-qcom-edp.o
+obj-$(CONFIG_PHY_QCOM_IPQ4019_USB)	+= phy-qcom-ipq4019-usb.o
+obj-$(CONFIG_PHY_QCOM_IPQ806X_SATA)	+= phy-qcom-ipq806x-sata.o
+obj-$(CONFIG_PHY_QCOM_M31_USB)		+= phy-qcom-m31.o
+obj-$(CONFIG_PHY_QCOM_M31_EUSB)		+= phy-qcom-m31-eusb2.o
+obj-$(CONFIG_PHY_QCOM_PCIE2)		+= phy-qcom-pcie2.o
+
+obj-$(CONFIG_PHY_QCOM_QMP_COMBO)	+= phy-qcom-qmp-combo.o phy-qcom-qmp-usbc.o
+obj-$(CONFIG_PHY_QCOM_QMP_PCIE)		+= phy-qcom-qmp-pcie.o
+obj-$(CONFIG_PHY_QCOM_QMP_PCIE_MULTIPHY)	+= phy-qcom-qmp-pcie-multiphy.o
+obj-$(CONFIG_PHY_QCOM_QMP_PCIE_8996)	+= phy-qcom-qmp-pcie-msm8996.o
+obj-$(CONFIG_PHY_QCOM_QMP_UFS)		+= phy-qcom-qmp-ufs.o
+obj-$(CONFIG_PHY_QCOM_QMP_USB)		+= phy-qcom-qmp-usb.o
+obj-$(CONFIG_PHY_QCOM_QMP_USB_LEGACY)	+= phy-qcom-qmp-usb-legacy.o
+
+obj-$(CONFIG_PHY_QCOM_QUSB2)		+= phy-qcom-qusb2.o
+obj-$(CONFIG_PHY_QCOM_EUSB2_REPEATER)	+= phy-qcom-eusb2-repeater.o
+obj-$(CONFIG_PHY_QCOM_UNIPHY_PCIE_28LP)	+= phy-qcom-uniphy-pcie-28lp.o
+obj-$(CONFIG_PHY_QCOM_USB_HS) 		+= phy-qcom-usb-hs.o
+obj-$(CONFIG_PHY_QCOM_USB_HSIC) 	+= phy-qcom-usb-hsic.o
+obj-$(CONFIG_PHY_QCOM_USB_HS_28NM)	+= phy-qcom-usb-hs-28nm.o
+obj-$(CONFIG_PHY_QCOM_USB_SS)		+= phy-qcom-usb-ss.o
+obj-$(CONFIG_PHY_QCOM_USB_SNPS_FEMTO_V2)+= phy-qcom-snps-femto-v2.o
+obj-$(CONFIG_PHY_QCOM_IPQ806X_USB)	+= phy-qcom-ipq806x-usb.o
+obj-$(CONFIG_PHY_QCOM_SGMII_ETH)	+= phy-qcom-sgmii-eth.o