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/ti/interface.c | 142 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 142 insertions(+) create mode 100644 drivers/clk/ti/interface.c (limited to 'drivers/clk/ti/interface.c') diff --git a/drivers/clk/ti/interface.c b/drivers/clk/ti/interface.c new file mode 100644 index 000000000..039c8075e --- /dev/null +++ b/drivers/clk/ti/interface.c @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * OMAP interface clock support + * + * Copyright (C) 2013 Texas Instruments, Inc. + * + * Tero Kristo + */ + +#include +#include +#include +#include +#include +#include "clock.h" + +#undef pr_fmt +#define pr_fmt(fmt) "%s: " fmt, __func__ + +static const struct clk_ops ti_interface_clk_ops = { + .init = &omap2_init_clk_clkdm, + .enable = &omap2_dflt_clk_enable, + .disable = &omap2_dflt_clk_disable, + .is_enabled = &omap2_dflt_clk_is_enabled, +}; + +static struct clk *_register_interface(struct device_node *node, + const char *name, + const char *parent_name, + struct clk_omap_reg *reg, u8 bit_idx, + const struct clk_hw_omap_ops *ops) +{ + struct clk_init_data init = { NULL }; + struct clk_hw_omap *clk_hw; + struct clk *clk; + + clk_hw = kzalloc_obj(*clk_hw); + if (!clk_hw) + return ERR_PTR(-ENOMEM); + + clk_hw->hw.init = &init; + clk_hw->ops = ops; + memcpy(&clk_hw->enable_reg, reg, sizeof(*reg)); + clk_hw->enable_bit = bit_idx; + + init.name = name; + init.ops = &ti_interface_clk_ops; + init.flags = 0; + + init.num_parents = 1; + init.parent_names = &parent_name; + + clk = of_ti_clk_register_omap_hw(node, &clk_hw->hw, name); + + if (IS_ERR(clk)) + kfree(clk_hw); + + return clk; +} + +static void __init _of_ti_interface_clk_setup(struct device_node *node, + const struct clk_hw_omap_ops *ops) +{ + struct clk *clk; + const char *parent_name; + struct clk_omap_reg reg; + u8 enable_bit = 0; + const char *name; + + if (ti_clk_get_reg_addr(node, 0, ®)) + return; + + enable_bit = reg.bit; + + parent_name = of_clk_get_parent_name(node, 0); + if (!parent_name) { + pr_err("%pOFn must have a parent\n", node); + return; + } + + name = ti_dt_clk_name(node); + clk = _register_interface(node, name, parent_name, ®, + enable_bit, ops); + + if (!IS_ERR(clk)) + of_clk_add_provider(node, of_clk_src_simple_get, clk); +} + +static void __init of_ti_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, &clkhwops_iclk_wait); +} +CLK_OF_DECLARE(ti_interface_clk, "ti,omap3-interface-clock", + of_ti_interface_clk_setup); + +static void __init of_ti_no_wait_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, &clkhwops_iclk); +} +CLK_OF_DECLARE(ti_no_wait_interface_clk, "ti,omap3-no-wait-interface-clock", + of_ti_no_wait_interface_clk_setup); + +#ifdef CONFIG_ARCH_OMAP3 +static void __init of_ti_hsotgusb_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, + &clkhwops_omap3430es2_iclk_hsotgusb_wait); +} +CLK_OF_DECLARE(ti_hsotgusb_interface_clk, "ti,omap3-hsotgusb-interface-clock", + of_ti_hsotgusb_interface_clk_setup); + +static void __init of_ti_dss_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, + &clkhwops_omap3430es2_iclk_dss_usbhost_wait); +} +CLK_OF_DECLARE(ti_dss_interface_clk, "ti,omap3-dss-interface-clock", + of_ti_dss_interface_clk_setup); + +static void __init of_ti_ssi_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, &clkhwops_omap3430es2_iclk_ssi_wait); +} +CLK_OF_DECLARE(ti_ssi_interface_clk, "ti,omap3-ssi-interface-clock", + of_ti_ssi_interface_clk_setup); + +static void __init of_ti_am35xx_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, &clkhwops_am35xx_ipss_wait); +} +CLK_OF_DECLARE(ti_am35xx_interface_clk, "ti,am35xx-interface-clock", + of_ti_am35xx_interface_clk_setup); +#endif + +#ifdef CONFIG_SOC_OMAP2430 +static void __init of_ti_omap2430_interface_clk_setup(struct device_node *node) +{ + _of_ti_interface_clk_setup(node, &clkhwops_omap2430_i2chs_wait); +} +CLK_OF_DECLARE(ti_omap2430_interface_clk, "ti,omap2430-interface-clock", + of_ti_omap2430_interface_clk_setup); +#endif -- cgit v1.3.1