From 0d6526f82c3cdefcca47f73f5fc08dc6f335eac6 Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Mon, 21 Sep 2026 17:37:22 -0700 Subject: sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling bug 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 Suggested-by: Chen Yu Signed-off-by: Tim Chen Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Kayra Cizmeci Cc: # v7.2.x Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com --- drivers/clk/qcom/common.h | 92 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 drivers/clk/qcom/common.h (limited to 'drivers/clk/qcom/common.h') diff --git a/drivers/clk/qcom/common.h b/drivers/clk/qcom/common.h new file mode 100644 index 000000000..6f2406f88 --- /dev/null +++ b/drivers/clk/qcom/common.h @@ -0,0 +1,92 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* Copyright (c) 2014, The Linux Foundation. All rights reserved. */ + +#ifndef __QCOM_CLK_COMMON_H__ +#define __QCOM_CLK_COMMON_H__ + +struct platform_device; +struct regmap_config; +struct clk_regmap; +struct qcom_reset_map; +struct regmap; +struct freq_tbl; +struct clk_hw; + +#define PLL_LOCK_COUNT_SHIFT 8 +#define PLL_LOCK_COUNT_MASK 0x3f +#define PLL_BIAS_COUNT_SHIFT 14 +#define PLL_BIAS_COUNT_MASK 0x3f +#define PLL_VOTE_FSM_ENA BIT(20) +#define PLL_VOTE_FSM_RESET BIT(21) + +struct qcom_icc_hws_data { + int master_id; + int slave_id; + int clk_id; +}; + +struct qcom_cc_driver_data { + struct clk_alpha_pll **alpha_plls; + size_t num_alpha_plls; + const u32 *clk_cbcrs; + size_t num_clk_cbcrs; + const struct clk_rcg_dfs_data *dfs_rcgs; + size_t num_dfs_rcgs; + void (*clk_regs_configure)(struct device *dev, struct regmap *regmap); +}; + +struct qcom_cc_desc { + const struct regmap_config *config; + struct clk_regmap **clks; + size_t num_clks; + const struct qcom_reset_map *resets; + size_t num_resets; + struct gdsc **gdscs; + size_t num_gdscs; + struct clk_hw **clk_hws; + size_t num_clk_hws; + const struct qcom_icc_hws_data *icc_hws; + size_t num_icc_hws; + unsigned int icc_first_node_id; + bool use_rpm; + const struct qcom_cc_driver_data *driver_data; +}; + +/** + * struct parent_map - map table for source select configuration values + * @src: source + * @cfg: configuration value + */ +struct parent_map { + u8 src; + u8 cfg; +}; + +extern const struct freq_tbl *qcom_find_freq(const struct freq_tbl *f, + unsigned long rate); +extern const struct freq_tbl *qcom_find_freq_floor(const struct freq_tbl *f, + unsigned long rate); +extern const struct freq_multi_tbl *qcom_find_freq_multi(const struct freq_multi_tbl *f, + unsigned long rate); +extern void +qcom_pll_set_fsm_mode(struct regmap *m, u32 reg, u8 bias_count, u8 lock_count); +extern int qcom_find_src_index(struct clk_hw *hw, const struct parent_map *map, + u8 src); +extern int qcom_find_cfg_index(struct clk_hw *hw, const struct parent_map *map, + u8 cfg); + +extern int qcom_cc_register_board_clk(struct device *dev, const char *path, + const char *name, unsigned long rate); +extern int qcom_cc_register_sleep_clk(struct device *dev); + +extern struct regmap *qcom_cc_map(struct platform_device *pdev, + const struct qcom_cc_desc *desc); +extern int qcom_cc_really_probe(struct device *dev, + const struct qcom_cc_desc *desc, + struct regmap *regmap); +extern int qcom_cc_probe(struct platform_device *pdev, + const struct qcom_cc_desc *desc); +extern int qcom_cc_probe_by_index(struct platform_device *pdev, int index, + const struct qcom_cc_desc *desc); + +#endif -- cgit v1.3.1