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/atarimouse.c | 153 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 153 insertions(+) create mode 100644 drivers/input/mouse/atarimouse.c (limited to 'drivers/input/mouse/atarimouse.c') diff --git a/drivers/input/mouse/atarimouse.c b/drivers/input/mouse/atarimouse.c new file mode 100644 index 000000000..b1219cc4d --- /dev/null +++ b/drivers/input/mouse/atarimouse.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Atari mouse driver for Linux/m68k + * + * Copyright (c) 2005 Michael Schmitz + * + * Based on: + * Amiga mouse driver for Linux/m68k + * + * Copyright (c) 2000-2002 Vojtech Pavlik + */ +/* + * The low level init and interrupt stuff is handled in arch/mm68k/atari/atakeyb.c + * (the keyboard ACIA also handles the mouse and joystick data, and the keyboard + * interrupt is shared with the MIDI ACIA so MIDI data also get handled there). + * This driver only deals with handing key events off to the input layer. + * + * Largely based on the old: + * + * Atari Mouse Driver for Linux + * by Robert de Vries (robert@and.nl) 19Jul93 + * + * 16 Nov 1994 Andreas Schwab + * Compatibility with busmouse + * Support for three button mouse (shamelessly stolen from MiNT) + * third button wired to one of the joystick directions on joystick 1 + * + * 1996/02/11 Andreas Schwab + * Module support + * Allow multiple open's + * + * Converted to use new generic busmouse code. 5 Apr 1998 + * Russell King + */ + + + +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include + +MODULE_AUTHOR("Michael Schmitz "); +MODULE_DESCRIPTION("Atari mouse driver"); +MODULE_LICENSE("GPL"); + +static int mouse_threshold[2] = {2, 2}; +module_param_array(mouse_threshold, int, NULL, 0); + +#ifdef FIXED_ATARI_JOYSTICK +extern int atari_mouse_buttons; +#endif + +static struct input_dev *atamouse_dev; + +static void atamouse_interrupt(char *buf) +{ + int buttons, dx, dy; + + buttons = (buf[0] & 1) | ((buf[0] & 2) << 1); +#ifdef FIXED_ATARI_JOYSTICK + buttons |= atari_mouse_buttons & 2; + atari_mouse_buttons = buttons; +#endif + + /* only relative events get here */ + dx = buf[1]; + dy = buf[2]; + + input_report_rel(atamouse_dev, REL_X, dx); + input_report_rel(atamouse_dev, REL_Y, dy); + + input_report_key(atamouse_dev, BTN_LEFT, buttons & 0x4); + input_report_key(atamouse_dev, BTN_MIDDLE, buttons & 0x2); + input_report_key(atamouse_dev, BTN_RIGHT, buttons & 0x1); + + input_sync(atamouse_dev); + + return; +} + +static int atamouse_open(struct input_dev *dev) +{ +#ifdef FIXED_ATARI_JOYSTICK + atari_mouse_buttons = 0; +#endif + ikbd_mouse_y0_top(); + ikbd_mouse_thresh(mouse_threshold[0], mouse_threshold[1]); + ikbd_mouse_rel_pos(); + atari_input_mouse_interrupt_hook = atamouse_interrupt; + + return 0; +} + +static void atamouse_close(struct input_dev *dev) +{ + ikbd_mouse_disable(); + atari_input_mouse_interrupt_hook = NULL; +} + +static int __init atamouse_init(void) +{ + int error; + + if (!MACH_IS_ATARI || !ATARIHW_PRESENT(ST_MFP)) + return -ENODEV; + + error = atari_keyb_init(); + if (error) + return error; + + atamouse_dev = input_allocate_device(); + if (!atamouse_dev) + return -ENOMEM; + + atamouse_dev->name = "Atari mouse"; + atamouse_dev->phys = "atamouse/input0"; + atamouse_dev->id.bustype = BUS_HOST; + atamouse_dev->id.vendor = 0x0001; + atamouse_dev->id.product = 0x0002; + atamouse_dev->id.version = 0x0100; + + atamouse_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REL); + atamouse_dev->relbit[0] = BIT_MASK(REL_X) | BIT_MASK(REL_Y); + atamouse_dev->keybit[BIT_WORD(BTN_LEFT)] = BIT_MASK(BTN_LEFT) | + BIT_MASK(BTN_MIDDLE) | BIT_MASK(BTN_RIGHT); + + atamouse_dev->open = atamouse_open; + atamouse_dev->close = atamouse_close; + + error = input_register_device(atamouse_dev); + if (error) { + input_free_device(atamouse_dev); + return error; + } + + return 0; +} + +static void __exit atamouse_exit(void) +{ + input_unregister_device(atamouse_dev); +} + +module_init(atamouse_init); +module_exit(atamouse_exit); -- cgit v1.3.1