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/sprd/gate.h | 168 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 drivers/clk/sprd/gate.h (limited to 'drivers/clk/sprd/gate.h') diff --git a/drivers/clk/sprd/gate.h b/drivers/clk/sprd/gate.h new file mode 100644 index 000000000..775519eb1 --- /dev/null +++ b/drivers/clk/sprd/gate.h @@ -0,0 +1,168 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +// +// Spreadtrum gate clock driver +// +// Copyright (C) 2017 Spreadtrum, Inc. +// Author: Chunyan Zhang + +#ifndef _SPRD_GATE_H_ +#define _SPRD_GATE_H_ + +#include "common.h" + +struct sprd_gate { + u32 enable_mask; + u16 flags; + u16 sc_offset; + u16 udelay; + + struct sprd_clk_common common; +}; + +/* + * sprd_gate->flags is used for: + * CLK_GATE_SET_TO_DISABLE BIT(0) + * CLK_GATE_HIWORD_MASK BIT(1) + * CLK_GATE_BIG_ENDIAN BIT(2) + * so we define new flags from BIT(3) + */ +#define SPRD_GATE_NON_AON BIT(3) /* not always powered on, check before read */ + +#define SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, _ops, _fn) \ + struct sprd_gate _struct = { \ + .enable_mask = _enable_mask, \ + .sc_offset = _sc_offset, \ + .flags = _gate_flags, \ + .udelay = _udelay, \ + .common = { \ + .regmap = NULL, \ + .reg = _reg, \ + .hw.init = _fn(_name, _parent, \ + _ops, _flags), \ + } \ + } + +#define SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, _ops) \ + SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, _ops, CLK_HW_INIT) + +#define SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset, \ + _enable_mask, _flags, _gate_flags, _ops) \ + SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, 0, _ops) + +#define SPRD_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset, \ + _enable_mask, _flags, _gate_flags) \ + SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, _sc_offset, \ + _enable_mask, _flags, _gate_flags, \ + &sprd_sc_gate_ops) + +#define SPRD_GATE_CLK(_struct, _name, _parent, _reg, \ + _enable_mask, _flags, _gate_flags) \ + SPRD_SC_GATE_CLK_OPS(_struct, _name, _parent, _reg, 0, \ + _enable_mask, _flags, _gate_flags, \ + &sprd_gate_ops) + +#define SPRD_PLL_SC_GATE_CLK(_struct, _name, _parent, _reg, _sc_offset, \ + _enable_mask, _flags, _gate_flags, \ + _udelay) \ + SPRD_SC_GATE_CLK_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, \ + &sprd_pll_sc_gate_ops) + + +#define SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, \ + _flags, _gate_flags, \ + _udelay, _ops) \ + SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, _ops, \ + CLK_HW_INIT_HW) + +#define SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _ops) \ + SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, \ + _flags, _gate_flags, 0, _ops) + +#define SPRD_SC_GATE_CLK_HW(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags) \ + SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, &sprd_sc_gate_ops) + +#define SPRD_GATE_CLK_HW(_struct, _name, _parent, _reg, \ + _enable_mask, _flags, _gate_flags) \ + SPRD_SC_GATE_CLK_HW_OPS(_struct, _name, _parent, _reg, 0, \ + _enable_mask, _flags, _gate_flags, \ + &sprd_gate_ops) + +#define SPRD_PLL_SC_GATE_CLK_HW(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay) \ + SPRD_SC_GATE_CLK_HW_OPS_UDELAY(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, \ + _flags, _gate_flags, _udelay, \ + &sprd_pll_sc_gate_ops) + +#define SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent, \ + _reg, _sc_offset, \ + _enable_mask, _flags, \ + _gate_flags, _udelay, _ops) \ + SPRD_SC_GATE_CLK_HW_INIT_FN(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay, _ops, \ + CLK_HW_INIT_FW_NAME) + +#define SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _ops) \ + SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent, \ + _reg, _sc_offset, \ + _enable_mask, _flags, \ + _gate_flags, 0, _ops) + +#define SPRD_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags) \ + SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, &sprd_sc_gate_ops) + +#define SPRD_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg, \ + _enable_mask, _flags, _gate_flags) \ + SPRD_SC_GATE_CLK_FW_NAME_OPS(_struct, _name, _parent, _reg, 0, \ + _enable_mask, _flags, _gate_flags, \ + &sprd_gate_ops) + +#define SPRD_PLL_SC_GATE_CLK_FW_NAME(_struct, _name, _parent, _reg, \ + _sc_offset, _enable_mask, _flags, \ + _gate_flags, _udelay) \ + SPRD_SC_GATE_CLK_FW_NAME_OPS_UDELAY(_struct, _name, _parent, \ + _reg, _sc_offset, \ + _enable_mask, _flags, \ + _gate_flags, _udelay, \ + &sprd_pll_sc_gate_ops) + +static inline struct sprd_gate *hw_to_sprd_gate(const struct clk_hw *hw) +{ + struct sprd_clk_common *common = hw_to_sprd_clk_common(hw); + + return container_of(common, struct sprd_gate, common); +} + +extern const struct clk_ops sprd_gate_ops; +extern const struct clk_ops sprd_sc_gate_ops; +extern const struct clk_ops sprd_pll_sc_gate_ops; + +#endif /* _SPRD_GATE_H_ */ -- cgit v1.3.1