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/video/fbdev/macmodes.h | 71 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 drivers/video/fbdev/macmodes.h (limited to 'drivers/video/fbdev/macmodes.h') diff --git a/drivers/video/fbdev/macmodes.h b/drivers/video/fbdev/macmodes.h new file mode 100644 index 000000000..b86ba08aa --- /dev/null +++ b/drivers/video/fbdev/macmodes.h @@ -0,0 +1,71 @@ +/* + * linux/drivers/video/macmodes.h -- Standard MacOS video modes + * + * Copyright (C) 1998 Geert Uytterhoeven + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file COPYING in the main directory of this archive for + * more details. + */ + +#ifndef _VIDEO_MACMODES_H +#define _VIDEO_MACMODES_H + + /* + * Video mode values. + * These are supposed to be the same as the values that Apple uses in + * MacOS. + */ + +#define VMODE_NVRAM 0 +#define VMODE_512_384_60I 1 /* 512x384, 60Hz interlaced (NTSC) */ +#define VMODE_512_384_60 2 /* 512x384, 60Hz */ +#define VMODE_640_480_50I 3 /* 640x480, 50Hz interlaced (PAL) */ +#define VMODE_640_480_60I 4 /* 640x480, 60Hz interlaced (NTSC) */ +#define VMODE_640_480_60 5 /* 640x480, 60Hz (VGA) */ +#define VMODE_640_480_67 6 /* 640x480, 67Hz */ +#define VMODE_640_870_75P 7 /* 640x870, 75Hz (portrait) */ +#define VMODE_768_576_50I 8 /* 768x576, 50Hz (PAL full frame) */ +#define VMODE_800_600_56 9 /* 800x600, 56Hz */ +#define VMODE_800_600_60 10 /* 800x600, 60Hz */ +#define VMODE_800_600_72 11 /* 800x600, 72Hz */ +#define VMODE_800_600_75 12 /* 800x600, 75Hz */ +#define VMODE_832_624_75 13 /* 832x624, 75Hz */ +#define VMODE_1024_768_60 14 /* 1024x768, 60Hz */ +#define VMODE_1024_768_70 15 /* 1024x768, 70Hz (or 72Hz?) */ +#define VMODE_1024_768_75V 16 /* 1024x768, 75Hz (VESA) */ +#define VMODE_1024_768_75 17 /* 1024x768, 75Hz */ +#define VMODE_1152_870_75 18 /* 1152x870, 75Hz */ +#define VMODE_1280_960_75 19 /* 1280x960, 75Hz */ +#define VMODE_1280_1024_75 20 /* 1280x1024, 75Hz */ +#define VMODE_1152_768_60 21 /* 1152x768, 60Hz Titanium PowerBook */ +#define VMODE_1600_1024_60 22 /* 1600x1024, 60Hz 22" Cinema Display */ +#define VMODE_MAX 22 +#define VMODE_CHOOSE 99 + +#define CMODE_NVRAM -1 +#define CMODE_CHOOSE -2 +#define CMODE_8 0 /* 8 bits/pixel */ +#define CMODE_16 1 /* 16 (actually 15) bits/pixel */ +#define CMODE_32 2 /* 32 (actually 24) bits/pixel */ + + +extern int mac_vmode_to_var(int vmode, int cmode, + struct fb_var_screeninfo *var); +extern int mac_var_to_vmode(const struct fb_var_screeninfo *var, int *vmode, + int *cmode); +extern int mac_map_monitor_sense(int sense); +extern int mac_find_mode(struct fb_var_screeninfo *var, + struct fb_info *info, + const char *mode_option, + unsigned int default_bpp); + + + /* + * Addresses in NVRAM where video mode and pixel size are stored. + */ + +#define NV_VMODE 0x140f +#define NV_CMODE 0x1410 + +#endif /* _VIDEO_MACMODES_H */ -- cgit v1.3.1