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, 45 insertions, 0 deletions

diff --git a/drivers/pinctrl/mediatek/Makefile b/drivers/pinctrl/mediatek/Makefile
new file mode 100644
index 000000000..6ee3833dc
--- /dev/null
+++ b/drivers/pinctrl/mediatek/Makefile
@@ -0,0 +1,45 @@
+# SPDX-License-Identifier: GPL-2.0
+# Core
+obj-$(CONFIG_EINT_MTK)			+= mtk-eint.o
+obj-$(CONFIG_PINCTRL_MTK)		+= pinctrl-mtk-common.o
+obj-$(CONFIG_PINCTRL_MTK_V2)		+= pinctrl-mtk-common-v2.o
+obj-$(CONFIG_PINCTRL_MTK_MTMIPS)	+= pinctrl-mtmips.o
+obj-$(CONFIG_PINCTRL_MTK_MOORE)		+= pinctrl-moore.o
+obj-$(CONFIG_PINCTRL_MTK_PARIS)		+= pinctrl-paris.o
+
+# SoC Drivers
+obj-$(CONFIG_PINCTRL_MT7620)		+= pinctrl-mt7620.o
+obj-$(CONFIG_PINCTRL_MT7621)		+= pinctrl-mt7621.o
+obj-$(CONFIG_PINCTRL_MT76X8)		+= pinctrl-mt76x8.o
+obj-$(CONFIG_PINCTRL_RT2880)		+= pinctrl-rt2880.o
+obj-$(CONFIG_PINCTRL_RT305X)		+= pinctrl-rt305x.o
+obj-$(CONFIG_PINCTRL_RT3883)		+= pinctrl-rt3883.o
+obj-$(CONFIG_PINCTRL_MT2701)		+= pinctrl-mt2701.o
+obj-$(CONFIG_PINCTRL_MT2712)		+= pinctrl-mt2712.o
+obj-$(CONFIG_PINCTRL_MT8135)		+= pinctrl-mt8135.o
+obj-$(CONFIG_PINCTRL_MT8127)		+= pinctrl-mt8127.o
+obj-$(CONFIG_PINCTRL_MT6765)		+= pinctrl-mt6765.o
+obj-$(CONFIG_PINCTRL_MT6779)		+= pinctrl-mt6779.o
+obj-$(CONFIG_PINCTRL_MT6795)		+= pinctrl-mt6795.o
+obj-$(CONFIG_PINCTRL_MT6797)		+= pinctrl-mt6797.o
+obj-$(CONFIG_PINCTRL_MT6858)		+= pinctrl-mt6858.o
+obj-$(CONFIG_PINCTRL_MT6878)		+= pinctrl-mt6878.o
+obj-$(CONFIG_PINCTRL_MT6893)		+= pinctrl-mt6893.o
+obj-$(CONFIG_PINCTRL_MT7622)		+= pinctrl-mt7622.o
+obj-$(CONFIG_PINCTRL_MT7623)		+= pinctrl-mt7623.o
+obj-$(CONFIG_PINCTRL_MT7629)		+= pinctrl-mt7629.o
+obj-$(CONFIG_PINCTRL_MT7981)		+= pinctrl-mt7981.o
+obj-$(CONFIG_PINCTRL_MT7986)		+= pinctrl-mt7986.o
+obj-$(CONFIG_PINCTRL_MT7988)		+= pinctrl-mt7988.o
+obj-$(CONFIG_PINCTRL_MT8167)		+= pinctrl-mt8167.o
+obj-$(CONFIG_PINCTRL_MT8173)		+= pinctrl-mt8173.o
+obj-$(CONFIG_PINCTRL_MT8183)		+= pinctrl-mt8183.o
+obj-$(CONFIG_PINCTRL_MT8186)		+= pinctrl-mt8186.o
+obj-$(CONFIG_PINCTRL_MT8188)		+= pinctrl-mt8188.o
+obj-$(CONFIG_PINCTRL_MT8189)            += pinctrl-mt8189.o
+obj-$(CONFIG_PINCTRL_MT8192)		+= pinctrl-mt8192.o
+obj-$(CONFIG_PINCTRL_MT8195)		+= pinctrl-mt8195.o
+obj-$(CONFIG_PINCTRL_MT8196)		+= pinctrl-mt8196.o
+obj-$(CONFIG_PINCTRL_MT8365)		+= pinctrl-mt8365.o
+obj-$(CONFIG_PINCTRL_MT8516)		+= pinctrl-mt8516.o
+obj-$(CONFIG_PINCTRL_MT6397)		+= pinctrl-mt6397.o