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/reset/reset-qcom-aoss.c | 132 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 insertions(+) create mode 100644 drivers/reset/reset-qcom-aoss.c (limited to 'drivers/reset/reset-qcom-aoss.c') diff --git a/drivers/reset/reset-qcom-aoss.c b/drivers/reset/reset-qcom-aoss.c new file mode 100644 index 000000000..93c84d70e --- /dev/null +++ b/drivers/reset/reset-qcom-aoss.c @@ -0,0 +1,132 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2018 The Linux Foundation. All rights reserved. + */ + +#include +#include +#include +#include +#include +#include +#include + +struct qcom_aoss_reset_map { + unsigned int reg; +}; + +struct qcom_aoss_desc { + const struct qcom_aoss_reset_map *resets; + size_t num_resets; +}; + +struct qcom_aoss_reset_data { + struct reset_controller_dev rcdev; + void __iomem *base; + const struct qcom_aoss_desc *desc; +}; + +static const struct qcom_aoss_reset_map sdm845_aoss_resets[] = { + [AOSS_CC_MSS_RESTART] = {0x10000}, + [AOSS_CC_CAMSS_RESTART] = {0x11000}, + [AOSS_CC_VENUS_RESTART] = {0x12000}, + [AOSS_CC_GPU_RESTART] = {0x13000}, + [AOSS_CC_DISPSS_RESTART] = {0x14000}, + [AOSS_CC_WCSS_RESTART] = {0x20000}, + [AOSS_CC_LPASS_RESTART] = {0x30000}, +}; + +static const struct qcom_aoss_desc sdm845_aoss_desc = { + .resets = sdm845_aoss_resets, + .num_resets = ARRAY_SIZE(sdm845_aoss_resets), +}; + +static inline struct qcom_aoss_reset_data *to_qcom_aoss_reset_data( + struct reset_controller_dev *rcdev) +{ + return container_of(rcdev, struct qcom_aoss_reset_data, rcdev); +} + +static int qcom_aoss_control_assert(struct reset_controller_dev *rcdev, + unsigned long idx) +{ + struct qcom_aoss_reset_data *data = to_qcom_aoss_reset_data(rcdev); + const struct qcom_aoss_reset_map *map = &data->desc->resets[idx]; + + writel(1, data->base + map->reg); + /* Wait 6 32kHz sleep cycles for reset */ + usleep_range(200, 300); + return 0; +} + +static int qcom_aoss_control_deassert(struct reset_controller_dev *rcdev, + unsigned long idx) +{ + struct qcom_aoss_reset_data *data = to_qcom_aoss_reset_data(rcdev); + const struct qcom_aoss_reset_map *map = &data->desc->resets[idx]; + + writel(0, data->base + map->reg); + /* Wait 6 32kHz sleep cycles for reset */ + usleep_range(200, 300); + return 0; +} + +static int qcom_aoss_control_reset(struct reset_controller_dev *rcdev, + unsigned long idx) +{ + qcom_aoss_control_assert(rcdev, idx); + + return qcom_aoss_control_deassert(rcdev, idx); +} + +static const struct reset_control_ops qcom_aoss_reset_ops = { + .reset = qcom_aoss_control_reset, + .assert = qcom_aoss_control_assert, + .deassert = qcom_aoss_control_deassert, +}; + +static int qcom_aoss_reset_probe(struct platform_device *pdev) +{ + struct qcom_aoss_reset_data *data; + struct device *dev = &pdev->dev; + const struct qcom_aoss_desc *desc; + + desc = of_device_get_match_data(dev); + if (!desc) + return -EINVAL; + + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); + if (!data) + return -ENOMEM; + + data->desc = desc; + data->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(data->base)) + return PTR_ERR(data->base); + + data->rcdev.owner = THIS_MODULE; + data->rcdev.ops = &qcom_aoss_reset_ops; + data->rcdev.nr_resets = desc->num_resets; + data->rcdev.of_node = dev->of_node; + + return devm_reset_controller_register(dev, &data->rcdev); +} + +static const struct of_device_id qcom_aoss_reset_of_match[] = { + { .compatible = "qcom,sdm845-aoss-cc", .data = &sdm845_aoss_desc }, + {} +}; +MODULE_DEVICE_TABLE(of, qcom_aoss_reset_of_match); + +static struct platform_driver qcom_aoss_reset_driver = { + .probe = qcom_aoss_reset_probe, + .driver = { + .name = "qcom_aoss_reset", + .of_match_table = qcom_aoss_reset_of_match, + }, +}; + +module_platform_driver(qcom_aoss_reset_driver); + +MODULE_DESCRIPTION("Qualcomm AOSS Reset Driver"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1