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, 56 insertions, 0 deletions

diff --git a/drivers/phy/Makefile b/drivers/phy/Makefile
new file mode 100644
index 000000000..d7aa516bc
--- /dev/null
+++ b/drivers/phy/Makefile
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the phy drivers.
+#
+
+obj-$(CONFIG_PHY_COMMON_PROPS)		+= phy-common-props.o
+obj-$(CONFIG_PHY_COMMON_PROPS_TEST)	+= phy-common-props-test.o
+obj-$(CONFIG_GENERIC_PHY)		+= phy-core.o
+obj-$(CONFIG_GENERIC_PHY_MIPI_DPHY)	+= phy-core-mipi-dphy.o
+obj-$(CONFIG_PHY_AIROHA_PCIE)		+= phy-airoha-pcie.o
+obj-$(CONFIG_PHY_CAN_TRANSCEIVER)	+= phy-can-transceiver.o
+obj-$(CONFIG_PHY_ECONET_PCIE)		+= phy-econet-pcie.o
+obj-$(CONFIG_PHY_EYEQ5_ETH)		+= phy-eyeq5-eth.o
+obj-$(CONFIG_PHY_GOOGLE_USB)		+= phy-google-usb.o
+obj-$(CONFIG_USB_LGM_PHY)		+= phy-lgm-usb.o
+obj-$(CONFIG_PHY_LPC18XX_USB_OTG)	+= phy-lpc18xx-usb-otg.o
+obj-$(CONFIG_PHY_NXP_PTN3222)		+= phy-nxp-ptn3222.o
+obj-$(CONFIG_PHY_NXP_TJA1145)		+= phy-nxp-tja1145.o
+obj-$(CONFIG_PHY_PISTACHIO_USB)		+= phy-pistachio-usb.o
+obj-$(CONFIG_PHY_SNPS_EUSB2)		+= phy-snps-eusb2.o
+obj-$(CONFIG_PHY_XGENE)			+= phy-xgene.o
+
+obj-$(CONFIG_GENERIC_PHY)		+= allwinner/	\
+					   amlogic/	\
+					   apple/	\
+					   axiado/	\
+					   broadcom/	\
+					   cadence/	\
+					   canaan/	\
+					   eswin/	\
+					   freescale/	\
+					   hisilicon/	\
+					   ingenic/	\
+					   intel/	\
+					   lantiq/	\
+					   marvell/	\
+					   mediatek/	\
+					   microchip/	\
+					   motorola/	\
+					   mscc/	\
+					   nuvoton/	\
+					   qualcomm/	\
+					   ralink/	\
+					   realtek/	\
+					   renesas/	\
+					   rockchip/	\
+					   samsung/	\
+					   socionext/	\
+					   sophgo/	\
+					   spacemit/	\
+					   st/		\
+					   starfive/	\
+					   sunplus/	\
+					   tegra/	\
+					   ti/		\
+					   xilinx/