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, 99 insertions, 0 deletions

diff --git a/drivers/mfd/mt6370.h b/drivers/mfd/mt6370.h
new file mode 100644
index 000000000..dd9ccc0a5
--- /dev/null
+++ b/drivers/mfd/mt6370.h
@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2022 Richtek Technology Corp.
+ *
+ * Author: ChiYuan Huang <cy_huang@richtek.com>
+ */
+
+#ifndef __MFD_MT6370_H__
+#define __MFD_MT6370_H__
+
+/* IRQ definitions */
+#define MT6370_IRQ_DIRCHGON		0
+#define MT6370_IRQ_CHG_TREG		4
+#define MT6370_IRQ_CHG_AICR		5
+#define MT6370_IRQ_CHG_MIVR		6
+#define MT6370_IRQ_PWR_RDY		7
+#define MT6370_IRQ_FL_CHG_VINOVP	11
+#define MT6370_IRQ_CHG_VSYSUV		12
+#define MT6370_IRQ_CHG_VSYSOV		13
+#define MT6370_IRQ_CHG_VBATOV		14
+#define MT6370_IRQ_CHG_VINOVPCHG	15
+#define MT6370_IRQ_TS_BAT_COLD		20
+#define MT6370_IRQ_TS_BAT_COOL		21
+#define MT6370_IRQ_TS_BAT_WARM		22
+#define MT6370_IRQ_TS_BAT_HOT		23
+#define MT6370_IRQ_TS_STATC		24
+#define MT6370_IRQ_CHG_FAULT		25
+#define MT6370_IRQ_CHG_STATC		26
+#define MT6370_IRQ_CHG_TMR		27
+#define MT6370_IRQ_CHG_BATABS		28
+#define MT6370_IRQ_CHG_ADPBAD		29
+#define MT6370_IRQ_CHG_RVP		30
+#define MT6370_IRQ_TSHUTDOWN		31
+#define MT6370_IRQ_CHG_IINMEAS		32
+#define MT6370_IRQ_CHG_ICCMEAS		33
+#define MT6370_IRQ_CHGDET_DONE		34
+#define MT6370_IRQ_WDTMR		35
+#define MT6370_IRQ_SSFINISH		36
+#define MT6370_IRQ_CHG_RECHG		37
+#define MT6370_IRQ_CHG_TERM		38
+#define MT6370_IRQ_CHG_IEOC		39
+#define MT6370_IRQ_ADC_DONE		40
+#define MT6370_IRQ_PUMPX_DONE		41
+#define MT6370_IRQ_BST_BATUV		45
+#define MT6370_IRQ_BST_MIDOV		46
+#define MT6370_IRQ_BST_OLP		47
+#define MT6370_IRQ_ATTACH		48
+#define MT6370_IRQ_DETACH		49
+#define MT6370_IRQ_HVDCP_STPDONE	51
+#define MT6370_IRQ_HVDCP_VBUSDET_DONE	52
+#define MT6370_IRQ_HVDCP_DET		53
+#define MT6370_IRQ_CHGDET		54
+#define MT6370_IRQ_DCDT			55
+#define MT6370_IRQ_DIRCHG_VGOK		59
+#define MT6370_IRQ_DIRCHG_WDTMR		60
+#define MT6370_IRQ_DIRCHG_UC		61
+#define MT6370_IRQ_DIRCHG_OC		62
+#define MT6370_IRQ_DIRCHG_OV		63
+#define MT6370_IRQ_OVPCTRL_SWON		67
+#define MT6370_IRQ_OVPCTRL_UVP_D	68
+#define MT6370_IRQ_OVPCTRL_UVP		69
+#define MT6370_IRQ_OVPCTRL_OVP_D	70
+#define MT6370_IRQ_OVPCTRL_OVP		71
+#define MT6370_IRQ_FLED_STRBPIN		72
+#define MT6370_IRQ_FLED_TORPIN		73
+#define MT6370_IRQ_FLED_TX		74
+#define MT6370_IRQ_FLED_LVF		75
+#define MT6370_IRQ_FLED2_SHORT		78
+#define MT6370_IRQ_FLED1_SHORT		79
+#define MT6370_IRQ_FLED2_STRB		80
+#define MT6370_IRQ_FLED1_STRB		81
+#define MT6370_IRQ_FLED2_STRB_TO	82
+#define MT6370_IRQ_FLED1_STRB_TO	83
+#define MT6370_IRQ_FLED2_TOR		84
+#define MT6370_IRQ_FLED1_TOR		85
+#define MT6370_IRQ_OTP			93
+#define MT6370_IRQ_VDDA_OVP		94
+#define MT6370_IRQ_VDDA_UV		95
+#define MT6370_IRQ_LDO_OC		103
+#define MT6370_IRQ_BLED_OCP		118
+#define MT6370_IRQ_BLED_OVP		119
+#define MT6370_IRQ_DSV_VNEG_OCP		123
+#define MT6370_IRQ_DSV_VPOS_OCP		124
+#define MT6370_IRQ_DSV_BST_OCP		125
+#define MT6370_IRQ_DSV_VNEG_SCP		126
+#define MT6370_IRQ_DSV_VPOS_SCP		127
+
+enum {
+	MT6370_USBC_I2C = 0,
+	MT6370_PMU_I2C,
+	MT6370_MAX_I2C
+};
+
+struct mt6370_info {
+	struct i2c_client *i2c[MT6370_MAX_I2C];
+	struct regmap_irq_chip_data *irq_data;
+};
+
+#endif /* __MFD_MT6375_H__ */