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, 63 insertions, 0 deletions

diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
new file mode 100644
index 000000000..f37971197
--- /dev/null
+++ b/drivers/usb/dwc3/Makefile
@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: GPL-2.0
+# define_trace.h needs to know how to find our header
+CFLAGS_trace.o				:= -I$(src)
+
+obj-$(CONFIG_USB_DWC3)			+= dwc3.o
+
+dwc3-y					:= core.o
+
+ifneq ($(CONFIG_TRACING),)
+	dwc3-y				+= trace.o
+endif
+
+ifneq ($(filter y,$(CONFIG_USB_DWC3_HOST) $(CONFIG_USB_DWC3_DUAL_ROLE)),)
+	dwc3-y				+= host.o
+endif
+
+ifneq ($(filter y,$(CONFIG_USB_DWC3_GADGET) $(CONFIG_USB_DWC3_DUAL_ROLE)),)
+	dwc3-y				+= gadget.o ep0.o
+endif
+
+ifneq ($(CONFIG_USB_DWC3_DUAL_ROLE),)
+	dwc3-y				+= drd.o
+endif
+
+ifneq ($(CONFIG_USB_DWC3_ULPI),)
+	dwc3-y				+= ulpi.o
+endif
+
+ifneq ($(CONFIG_DEBUG_FS),)
+	dwc3-y				+= debugfs.o
+endif
+
+##
+# Platform-specific glue layers go here
+#
+# NOTICE: Make sure your glue layer doesn't depend on anything
+# which is arch-specific and that it compiles on all situations.
+#
+# We want to keep this requirement in order to be able to compile
+# the entire driver (with all its glue layers) on several architectures
+# and make sure it compiles fine. This will also help with allmodconfig
+# and allyesconfig builds.
+##
+
+obj-$(CONFIG_USB_DWC3_AM62)		+= dwc3-am62.o
+obj-$(CONFIG_USB_DWC3_APPLE)		+= dwc3-apple.o
+obj-$(CONFIG_USB_DWC3_OMAP)		+= dwc3-omap.o
+obj-$(CONFIG_USB_DWC3_EXYNOS)		+= dwc3-exynos.o
+obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
+obj-$(CONFIG_USB_DWC3_HAPS)		+= dwc3-haps.o
+obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
+obj-$(CONFIG_USB_DWC3_MESON_G12A)	+= dwc3-meson-g12a.o
+obj-$(CONFIG_USB_DWC3_OF_SIMPLE)	+= dwc3-of-simple.o
+obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
+obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom.o
+obj-$(CONFIG_USB_DWC3_QCOM)		+= dwc3-qcom-legacy.o
+obj-$(CONFIG_USB_DWC3_IMX8MP)		+= dwc3-imx8mp.o
+obj-$(CONFIG_USB_DWC3_IMX)		+= dwc3-imx.o
+obj-$(CONFIG_USB_DWC3_XILINX)		+= dwc3-xilinx.o
+obj-$(CONFIG_USB_DWC3_OCTEON)		+= dwc3-octeon.o
+obj-$(CONFIG_USB_DWC3_RTK)		+= dwc3-rtk.o
+obj-$(CONFIG_USB_DWC3_GENERIC_PLAT)	+= dwc3-generic-plat.o
+obj-$(CONFIG_USB_DWC3_GOOGLE)		+= dwc3-google.o