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, 119 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/goodix.h b/drivers/input/touchscreen/goodix.h
new file mode 100644
index 000000000..0d1e8a8d2
--- /dev/null
+++ b/drivers/input/touchscreen/goodix.h
@@ -0,0 +1,119 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __GOODIX_H__
+#define __GOODIX_H__
+
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
+#include <linux/regulator/consumer.h>
+
+/* Register defines */
+#define GOODIX_REG_MISCTL_DSP_CTL		0x4010
+#define GOODIX_REG_MISCTL_SRAM_BANK		0x4048
+#define GOODIX_REG_MISCTL_MEM_CD_EN		0x4049
+#define GOODIX_REG_MISCTL_CACHE_EN		0x404B
+#define GOODIX_REG_MISCTL_TMR0_EN		0x40B0
+#define GOODIX_REG_MISCTL_SWRST			0x4180
+#define GOODIX_REG_MISCTL_CPU_SWRST_PULSE	0x4184
+#define GOODIX_REG_MISCTL_BOOTCTL		0x4190
+#define GOODIX_REG_MISCTL_BOOT_OPT		0x4218
+#define GOODIX_REG_MISCTL_BOOT_CTL		0x5094
+
+#define GOODIX_REG_FW_SIG			0x8000
+#define GOODIX_FW_SIG_LEN			10
+
+#define GOODIX_REG_MAIN_CLK			0x8020
+#define GOODIX_MAIN_CLK_LEN			6
+
+#define GOODIX_REG_COMMAND			0x8040
+#define GOODIX_CMD_SCREEN_OFF			0x05
+
+#define GOODIX_REG_SW_WDT			0x8041
+
+#define GOODIX_REG_REQUEST			0x8043
+#define GOODIX_RQST_RESPONDED			0x00
+#define GOODIX_RQST_CONFIG			0x01
+#define GOODIX_RQST_BAK_REF			0x02
+#define GOODIX_RQST_RESET			0x03
+#define GOODIX_RQST_MAIN_CLOCK			0x04
+/*
+ * Unknown request which gets send by the controller aprox.
+ * every 34 seconds once it is up and running.
+ */
+#define GOODIX_RQST_UNKNOWN			0x06
+#define GOODIX_RQST_IDLE			0xFF
+
+#define GOODIX_REG_STATUS			0x8044
+
+#define GOODIX_GT1X_REG_CONFIG_DATA		0x8050
+#define GOODIX_GT9X_REG_CONFIG_DATA		0x8047
+#define GOODIX_REG_ID				0x8140
+#define GOODIX_READ_COOR_ADDR			0x814E
+#define GOODIX_REG_BAK_REF			0x99D0
+
+#define GOODIX_ID_MAX_LEN			4
+#define GOODIX_CONFIG_MAX_LENGTH		240
+#define GOODIX_MAX_KEYS				7
+
+enum goodix_irq_pin_access_method {
+	IRQ_PIN_ACCESS_NONE,
+	IRQ_PIN_ACCESS_GPIO,
+	IRQ_PIN_ACCESS_ACPI_GPIO,
+	IRQ_PIN_ACCESS_ACPI_METHOD,
+};
+
+struct goodix_ts_data;
+
+struct goodix_chip_data {
+	u16 config_addr;
+	int config_len;
+	int (*check_config)(struct goodix_ts_data *ts, const u8 *cfg, int len);
+	void (*calc_config_checksum)(struct goodix_ts_data *ts);
+};
+
+struct goodix_ts_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct input_dev *input_pen;
+	const struct goodix_chip_data *chip;
+	const char *firmware_name;
+	struct touchscreen_properties prop;
+	unsigned int max_touch_num;
+	unsigned int int_trigger_type;
+	struct regulator *avdd28;
+	struct regulator *vddio;
+	struct gpio_desc *gpiod_int;
+	struct gpio_desc *gpiod_rst;
+	int gpio_count;
+	int gpio_int_idx;
+	char id[GOODIX_ID_MAX_LEN + 1];
+	char cfg_name[64];
+	u16 version;
+	bool reset_controller_at_probe;
+	bool load_cfg_from_disk;
+	int pen_input_registered;
+	struct completion firmware_loading_complete;
+	unsigned long irq_flags;
+	enum goodix_irq_pin_access_method irq_pin_access_method;
+	unsigned int contact_size;
+	u8 config[GOODIX_CONFIG_MAX_LENGTH];
+	unsigned short keymap[GOODIX_MAX_KEYS];
+	u8 main_clk[GOODIX_MAIN_CLK_LEN];
+	int bak_ref_len;
+	u8 *bak_ref;
+};
+
+int goodix_i2c_read(struct i2c_client *client, u16 reg, u8 *buf, int len);
+int goodix_i2c_write(struct i2c_client *client, u16 reg, const u8 *buf, int len);
+int goodix_i2c_write_u8(struct i2c_client *client, u16 reg, u8 value);
+int goodix_send_cfg(struct goodix_ts_data *ts, const u8 *cfg, int len);
+int goodix_int_sync(struct goodix_ts_data *ts);
+int goodix_reset_no_int_sync(struct goodix_ts_data *ts);
+
+int goodix_firmware_check(struct goodix_ts_data *ts);
+bool goodix_handle_fw_request(struct goodix_ts_data *ts);
+void goodix_save_bak_ref(struct goodix_ts_data *ts);
+
+#endif