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/input/touchscreen/tsc2005.c | 89 +++++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) create mode 100644 drivers/input/touchscreen/tsc2005.c (limited to 'drivers/input/touchscreen/tsc2005.c') diff --git a/drivers/input/touchscreen/tsc2005.c b/drivers/input/touchscreen/tsc2005.c new file mode 100644 index 000000000..6fe8b41b3 --- /dev/null +++ b/drivers/input/touchscreen/tsc2005.c @@ -0,0 +1,89 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * TSC2005 touchscreen driver + * + * Copyright (C) 2006-2010 Nokia Corporation + * Copyright (C) 2015 QWERTY Embedded Design + * Copyright (C) 2015 EMAC Inc. + * + * Based on original tsc2005.c by Lauri Leukkunen + */ + +#include +#include +#include +#include +#include +#include "tsc200x-core.h" + +static const struct input_id tsc2005_input_id = { + .bustype = BUS_SPI, + .product = 2005, +}; + +static int tsc2005_cmd(struct device *dev, u8 cmd) +{ + u8 tx = TSC200X_CMD | TSC200X_CMD_12BIT | cmd; + struct spi_transfer xfer = { + .tx_buf = &tx, + .len = 1, + .bits_per_word = 8, + }; + struct spi_message msg; + struct spi_device *spi = to_spi_device(dev); + int error; + + spi_message_init(&msg); + spi_message_add_tail(&xfer, &msg); + + error = spi_sync(spi, &msg); + if (error) { + dev_err(dev, "%s: failed, command: %x, spi error: %d\n", + __func__, cmd, error); + return error; + } + + return 0; +} + +static int tsc2005_probe(struct spi_device *spi) +{ + int error; + + spi->mode = SPI_MODE_0; + spi->bits_per_word = 8; + if (!spi->max_speed_hz) + spi->max_speed_hz = TSC2005_SPI_MAX_SPEED_HZ; + + error = spi_setup(spi); + if (error) + return error; + + return tsc200x_probe(&spi->dev, spi->irq, &tsc2005_input_id, + devm_regmap_init_spi(spi, &tsc200x_regmap_config), + tsc2005_cmd); +} + +#ifdef CONFIG_OF +static const struct of_device_id tsc2005_of_match[] = { + { .compatible = "ti,tsc2005" }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, tsc2005_of_match); +#endif + +static struct spi_driver tsc2005_driver = { + .driver = { + .name = "tsc2005", + .dev_groups = tsc200x_groups, + .of_match_table = of_match_ptr(tsc2005_of_match), + .pm = pm_sleep_ptr(&tsc200x_pm_ops), + }, + .probe = tsc2005_probe, +}; +module_spi_driver(tsc2005_driver); + +MODULE_AUTHOR("Michael Welling "); +MODULE_DESCRIPTION("TSC2005 Touchscreen Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("spi:tsc2005"); -- cgit v1.3.1