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, 149 insertions, 0 deletions

diff --git a/include/dt-bindings/clock/r9a06g032-sysctrl.h b/include/dt-bindings/clock/r9a06g032-sysctrl.h
new file mode 100644
index 000000000..d9d7b8b4f
--- /dev/null
+++ b/include/dt-bindings/clock/r9a06g032-sysctrl.h
@@ -0,0 +1,149 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * R9A06G032 sysctrl IDs
+ *
+ * Copyright (C) 2018 Renesas Electronics Europe Limited
+ *
+ * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
+ */
+
+#ifndef __DT_BINDINGS_R9A06G032_SYSCTRL_H__
+#define __DT_BINDINGS_R9A06G032_SYSCTRL_H__
+
+#define R9A06G032_CLK_PLL_USB		1
+#define R9A06G032_CLK_48		1	/* AKA CLK_PLL_USB */
+#define R9A06G032_MSEBIS_CLK		3	/* AKA CLKOUT_D16 */
+#define R9A06G032_MSEBIM_CLK		3	/* AKA CLKOUT_D16 */
+#define R9A06G032_CLK_DDRPHY_PLLCLK	5	/* AKA CLKOUT_D1OR2 */
+#define R9A06G032_CLK50			6	/* AKA CLKOUT_D20 */
+#define R9A06G032_CLK25			7	/* AKA CLKOUT_D40 */
+#define R9A06G032_CLK125		9	/* AKA CLKOUT_D8 */
+#define R9A06G032_CLK_P5_PG1		17	/* AKA DIV_P5_PG */
+#define R9A06G032_CLK_REF_SYNC		21	/* AKA DIV_REF_SYNC */
+#define R9A06G032_CLK_25_PG4		26
+#define R9A06G032_CLK_25_PG5		27
+#define R9A06G032_CLK_25_PG6		28
+#define R9A06G032_CLK_25_PG7		29
+#define R9A06G032_CLK_25_PG8		30
+#define R9A06G032_CLK_ADC		31
+#define R9A06G032_CLK_ECAT100		32
+#define R9A06G032_CLK_HSR100		33
+#define R9A06G032_CLK_I2C0		34
+#define R9A06G032_CLK_I2C1		35
+#define R9A06G032_CLK_MII_REF		36
+#define R9A06G032_CLK_NAND		37
+#define R9A06G032_CLK_NOUSBP2_PG6	38
+#define R9A06G032_CLK_P1_PG2		39
+#define R9A06G032_CLK_P1_PG3		40
+#define R9A06G032_CLK_P1_PG4		41
+#define R9A06G032_CLK_P4_PG3		42
+#define R9A06G032_CLK_P4_PG4		43
+#define R9A06G032_CLK_P6_PG1		44
+#define R9A06G032_CLK_P6_PG2		45
+#define R9A06G032_CLK_P6_PG3		46
+#define R9A06G032_CLK_P6_PG4		47
+#define R9A06G032_CLK_PCI_USB		48
+#define R9A06G032_CLK_QSPI0		49
+#define R9A06G032_CLK_QSPI1		50
+#define R9A06G032_CLK_RGMII_REF		51
+#define R9A06G032_CLK_RMII_REF		52
+#define R9A06G032_CLK_SDIO0		53
+#define R9A06G032_CLK_SDIO1		54
+#define R9A06G032_CLK_SERCOS100		55
+#define R9A06G032_CLK_SLCD		56
+#define R9A06G032_CLK_SPI0		57
+#define R9A06G032_CLK_SPI1		58
+#define R9A06G032_CLK_SPI2		59
+#define R9A06G032_CLK_SPI3		60
+#define R9A06G032_CLK_SPI4		61
+#define R9A06G032_CLK_SPI5		62
+#define R9A06G032_CLK_SWITCH		63
+#define R9A06G032_HCLK_ECAT125		65
+#define R9A06G032_HCLK_PINCONFIG	66
+#define R9A06G032_HCLK_SERCOS		67
+#define R9A06G032_HCLK_SGPIO2		68
+#define R9A06G032_HCLK_SGPIO3		69
+#define R9A06G032_HCLK_SGPIO4		70
+#define R9A06G032_HCLK_TIMER0		71
+#define R9A06G032_HCLK_TIMER1		72
+#define R9A06G032_HCLK_USBF		73
+#define R9A06G032_HCLK_USBH		74
+#define R9A06G032_HCLK_USBPM		75
+#define R9A06G032_CLK_48_PG_F		76
+#define R9A06G032_CLK_48_PG4		77
+#define R9A06G032_CLK_DDRPHY_PCLK	81	/* AKA CLK_REF_SYNC_D4 */
+#define R9A06G032_CLK_FW		81	/* AKA CLK_REF_SYNC_D4 */
+#define R9A06G032_CLK_CRYPTO		81	/* AKA CLK_REF_SYNC_D4 */
+#define R9A06G032_CLK_WATCHDOG		82	/* AKA CLK_REF_SYNC_D8 */
+#define R9A06G032_CLK_A7MP		84	/* AKA DIV_CA7 */
+#define R9A06G032_HCLK_CAN0		85
+#define R9A06G032_HCLK_CAN1		86
+#define R9A06G032_HCLK_DELTASIGMA	87
+#define R9A06G032_HCLK_PWMPTO		88
+#define R9A06G032_HCLK_RSV		89
+#define R9A06G032_HCLK_SGPIO0		90
+#define R9A06G032_HCLK_SGPIO1		91
+#define R9A06G032_RTOS_MDC		92
+#define R9A06G032_CLK_CM3		93
+#define R9A06G032_CLK_DDRC		94
+#define R9A06G032_CLK_ECAT25		95
+#define R9A06G032_CLK_HSR50		96
+#define R9A06G032_CLK_HW_RTOS		97
+#define R9A06G032_CLK_SERCOS50		98
+#define R9A06G032_HCLK_ADC		99
+#define R9A06G032_HCLK_CM3		100
+#define R9A06G032_HCLK_CRYPTO_EIP150	101
+#define R9A06G032_HCLK_CRYPTO_EIP93	102
+#define R9A06G032_HCLK_DDRC		103
+#define R9A06G032_HCLK_DMA0		104
+#define R9A06G032_HCLK_DMA1		105
+#define R9A06G032_HCLK_GMAC0		106
+#define R9A06G032_HCLK_GMAC1		107
+#define R9A06G032_HCLK_GPIO0		108
+#define R9A06G032_HCLK_GPIO1		109
+#define R9A06G032_HCLK_GPIO2		110
+#define R9A06G032_HCLK_HSR		111
+#define R9A06G032_HCLK_I2C0		112
+#define R9A06G032_HCLK_I2C1		113
+#define R9A06G032_HCLK_LCD		114
+#define R9A06G032_HCLK_MSEBI_M		115
+#define R9A06G032_HCLK_MSEBI_S		116
+#define R9A06G032_HCLK_NAND		117
+#define R9A06G032_HCLK_PG_I		118
+#define R9A06G032_HCLK_PG19		119
+#define R9A06G032_HCLK_PG20		120
+#define R9A06G032_HCLK_PG3		121
+#define R9A06G032_HCLK_PG4		122
+#define R9A06G032_HCLK_QSPI0		123
+#define R9A06G032_HCLK_QSPI1		124
+#define R9A06G032_HCLK_ROM		125
+#define R9A06G032_HCLK_RTC		126
+#define R9A06G032_HCLK_SDIO0		127
+#define R9A06G032_HCLK_SDIO1		128
+#define R9A06G032_HCLK_SEMAP		129
+#define R9A06G032_HCLK_SPI0		130
+#define R9A06G032_HCLK_SPI1		131
+#define R9A06G032_HCLK_SPI2		132
+#define R9A06G032_HCLK_SPI3		133
+#define R9A06G032_HCLK_SPI4		134
+#define R9A06G032_HCLK_SPI5		135
+#define R9A06G032_HCLK_SWITCH		136
+#define R9A06G032_HCLK_SWITCH_RG	137
+#define R9A06G032_HCLK_UART0		138
+#define R9A06G032_HCLK_UART1		139
+#define R9A06G032_HCLK_UART2		140
+#define R9A06G032_HCLK_UART3		141
+#define R9A06G032_HCLK_UART4		142
+#define R9A06G032_HCLK_UART5		143
+#define R9A06G032_HCLK_UART6		144
+#define R9A06G032_HCLK_UART7		145
+#define R9A06G032_CLK_UART0		146
+#define R9A06G032_CLK_UART1		147
+#define R9A06G032_CLK_UART2		148
+#define R9A06G032_CLK_UART3		149
+#define R9A06G032_CLK_UART4		150
+#define R9A06G032_CLK_UART5		151
+#define R9A06G032_CLK_UART6		152
+#define R9A06G032_CLK_UART7		153
+
+#endif /* __DT_BINDINGS_R9A06G032_SYSCTRL_H__ */