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/hfpll.c | 167 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 drivers/clk/qcom/hfpll.c (limited to 'drivers/clk/qcom/hfpll.c') diff --git a/drivers/clk/qcom/hfpll.c b/drivers/clk/qcom/hfpll.c new file mode 100644 index 000000000..385964196 --- /dev/null +++ b/drivers/clk/qcom/hfpll.c @@ -0,0 +1,167 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2018, The Linux Foundation. All rights reserved. + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "clk-regmap.h" +#include "clk-hfpll.h" + +static const struct hfpll_data qcs404 = { + .mode_reg = 0x00, + .l_reg = 0x04, + .m_reg = 0x08, + .n_reg = 0x0c, + .user_reg = 0x10, + .config_reg = 0x14, + .config_val = 0x430405d, + .status_reg = 0x1c, + .lock_bit = 16, + + .user_val = 0x8, + .user_vco_mask = 0x100000, + .low_vco_max_rate = 1248000000, + .min_rate = 537600000UL, + .max_rate = 2900000000UL, +}; + +static const struct hfpll_data msm8976_a53 = { + .mode_reg = 0x00, + .l_reg = 0x04, + .m_reg = 0x08, + .n_reg = 0x0c, + .user_reg = 0x10, + .config_reg = 0x14, + .config_val = 0x341600, + .status_reg = 0x1c, + .lock_bit = 16, + + .l_val = 0x35, + .user_val = 0x109, + .min_rate = 902400000UL, + .max_rate = 1478400000UL, +}; + +static const struct hfpll_data msm8976_a72 = { + .mode_reg = 0x00, + .l_reg = 0x04, + .m_reg = 0x08, + .n_reg = 0x0c, + .user_reg = 0x10, + .config_reg = 0x14, + .config_val = 0x4e0405d, + .status_reg = 0x1c, + .lock_bit = 16, + + .l_val = 0x3e, + .user_val = 0x100109, + .min_rate = 940800000UL, + .max_rate = 2016000000UL, +}; + +static const struct hfpll_data msm8976_cci = { + .mode_reg = 0x00, + .l_reg = 0x04, + .m_reg = 0x08, + .n_reg = 0x0c, + .user_reg = 0x10, + .config_reg = 0x14, + .config_val = 0x141400, + .status_reg = 0x1c, + .lock_bit = 16, + + .l_val = 0x20, + .user_val = 0x100109, + .min_rate = 556800000UL, + .max_rate = 902400000UL, +}; + +static const struct of_device_id qcom_hfpll_match_table[] = { + { .compatible = "qcom,msm8976-hfpll-a53", .data = &msm8976_a53 }, + { .compatible = "qcom,msm8976-hfpll-a72", .data = &msm8976_a72 }, + { .compatible = "qcom,msm8976-hfpll-cci", .data = &msm8976_cci }, + { .compatible = "qcom,qcs404-hfpll", .data = &qcs404 }, + /* Deprecated in bindings */ + { .compatible = "qcom,hfpll", .data = &qcs404 }, + { } +}; +MODULE_DEVICE_TABLE(of, qcom_hfpll_match_table); + +static const struct regmap_config hfpll_regmap_config = { + .reg_bits = 32, + .reg_stride = 4, + .val_bits = 32, + .max_register = 0x30, +}; + +static int qcom_hfpll_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + void __iomem *base; + struct regmap *regmap; + struct clk_hfpll *h; + struct clk_init_data init = { + .num_parents = 1, + .ops = &clk_ops_hfpll, + /* + * rather than marking the clock critical and forcing the clock + * to be always enabled, we make sure that the clock is not + * disabled: the firmware remains responsible of enabling this + * clock (for more info check the commit log) + */ + .flags = CLK_IGNORE_UNUSED, + }; + int ret; + struct clk_parent_data pdata = { .index = 0 }; + + h = devm_kzalloc(dev, sizeof(*h), GFP_KERNEL); + if (!h) + return -ENOMEM; + + base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); + if (IS_ERR(base)) + return PTR_ERR(base); + + regmap = devm_regmap_init_mmio(&pdev->dev, base, &hfpll_regmap_config); + if (IS_ERR(regmap)) + return PTR_ERR(regmap); + + if (of_property_read_string_index(dev->of_node, "clock-output-names", + 0, &init.name)) + return -ENODEV; + + init.parent_data = &pdata; + + h->d = of_device_get_match_data(&pdev->dev); + h->clkr.hw.init = &init; + spin_lock_init(&h->lock); + + ret = devm_clk_register_regmap(dev, &h->clkr); + if (ret) { + dev_err(dev, "failed to register regmap clock: %d\n", ret); + return ret; + } + + return devm_of_clk_add_hw_provider(dev, of_clk_hw_simple_get, + &h->clkr.hw); +} + +static struct platform_driver qcom_hfpll_driver = { + .probe = qcom_hfpll_probe, + .driver = { + .name = "qcom-hfpll", + .of_match_table = qcom_hfpll_match_table, + }, +}; +module_platform_driver(qcom_hfpll_driver); + +MODULE_DESCRIPTION("QCOM HFPLL Clock Driver"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:qcom-hfpll"); -- cgit v1.3.1