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/mouse/amimouse.c | 150 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 drivers/input/mouse/amimouse.c (limited to 'drivers/input/mouse/amimouse.c') diff --git a/drivers/input/mouse/amimouse.c b/drivers/input/mouse/amimouse.c new file mode 100644 index 000000000..d203c2a6c --- /dev/null +++ b/drivers/input/mouse/amimouse.c @@ -0,0 +1,150 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Amiga mouse driver for Linux/m68k + * + * Copyright (c) 2000-2002 Vojtech Pavlik + * + * Based on the work of: + * Michael Rausch James Banks + * Matther Dillon David Giller + * Nathan Laredo Linus Torvalds + * Johan Myreen Jes Sorensen + * Russell King + */ + + +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Vojtech Pavlik "); +MODULE_DESCRIPTION("Amiga mouse driver"); +MODULE_LICENSE("GPL"); + +static int amimouse_lastx, amimouse_lasty; + +static irqreturn_t amimouse_interrupt(int irq, void *data) +{ + struct input_dev *dev = data; + unsigned short joy0dat, potgor; + int nx, ny, dx, dy; + + joy0dat = amiga_custom.joy0dat; + + nx = joy0dat & 0xff; + ny = joy0dat >> 8; + + dx = nx - amimouse_lastx; + dy = ny - amimouse_lasty; + + if (dx < -127) dx = (256 + nx) - amimouse_lastx; + if (dx > 127) dx = (nx - 256) - amimouse_lastx; + if (dy < -127) dy = (256 + ny) - amimouse_lasty; + if (dy > 127) dy = (ny - 256) - amimouse_lasty; + + amimouse_lastx = nx; + amimouse_lasty = ny; + + potgor = amiga_custom.potgor; + + input_report_rel(dev, REL_X, dx); + input_report_rel(dev, REL_Y, dy); + + input_report_key(dev, BTN_LEFT, ciaa.pra & 0x40); + input_report_key(dev, BTN_MIDDLE, potgor & 0x0100); + input_report_key(dev, BTN_RIGHT, potgor & 0x0400); + + input_sync(dev); + + return IRQ_HANDLED; +} + +static int amimouse_open(struct input_dev *dev) +{ + unsigned short joy0dat; + int error; + + joy0dat = amiga_custom.joy0dat; + + amimouse_lastx = joy0dat & 0xff; + amimouse_lasty = joy0dat >> 8; + + error = request_irq(IRQ_AMIGA_VERTB, amimouse_interrupt, 0, "amimouse", + dev); + if (error) + dev_err(&dev->dev, "Can't allocate irq %d\n", IRQ_AMIGA_VERTB); + + return error; +} + +static void amimouse_close(struct input_dev *dev) +{ + free_irq(IRQ_AMIGA_VERTB, dev); +} + +static int __init amimouse_probe(struct platform_device *pdev) +{ + int err; + struct input_dev *dev; + + dev = input_allocate_device(); + if (!dev) + return -ENOMEM; + + dev->name = pdev->name; + dev->phys = "amimouse/input0"; + dev->id.bustype = BUS_AMIGA; + dev->id.vendor = 0x0001; + dev->id.product = 0x0002; + dev->id.version = 0x0100; + + dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL); + dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y); + dev->keybit[BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) | + BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT); + dev->open = amimouse_open; + dev->close = amimouse_close; + dev->dev.parent = &pdev->dev; + + err = input_register_device(dev); + if (err) { + input_free_device(dev); + return err; + } + + platform_set_drvdata(pdev, dev); + + return 0; +} + +static void __exit amimouse_remove(struct platform_device *pdev) +{ + struct input_dev *dev = platform_get_drvdata(pdev); + + input_unregister_device(dev); +} + +/* + * amimouse_remove() lives in .exit.text. For drivers registered via + * module_platform_driver_probe() this is ok because they cannot get unbound at + * runtime. So mark the driver struct with __refdata to prevent modpost + * triggering a section mismatch warning. + */ +static struct platform_driver amimouse_driver __refdata = { + .remove = __exit_p(amimouse_remove), + .driver = { + .name = "amiga-mouse", + }, +}; + +module_platform_driver_probe(amimouse_driver, amimouse_probe); + +MODULE_ALIAS("platform:amiga-mouse"); -- cgit v1.3.1