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/controlfb.h | 143 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 143 insertions(+) create mode 100644 drivers/video/fbdev/controlfb.h (limited to 'drivers/video/fbdev/controlfb.h') diff --git a/drivers/video/fbdev/controlfb.h b/drivers/video/fbdev/controlfb.h new file mode 100644 index 000000000..e779cca51 --- /dev/null +++ b/drivers/video/fbdev/controlfb.h @@ -0,0 +1,143 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * controlfb_hw.h: Constants of all sorts for controlfb + * + * Copyright (C) 1998 Daniel Jacobowitz + * + * Based on an awful lot of code, including: + * + * control.c: Console support for PowerMac "control" display adaptor. + * Copyright (C) 1996 Paul Mackerras. + * + * The so far unpublished platinumfb.c + * Copyright (C) 1998 Jon Howell + */ + +/* + * Structure of the registers for the RADACAL colormap device. + */ +struct cmap_regs { + unsigned char addr; /* index for both cmap and misc registers */ + char pad1[15]; + unsigned char crsr; /* cursor palette */ + char pad2[15]; + unsigned char dat; /* RADACAL misc register data */ + char pad3[15]; + unsigned char lut; /* cmap data */ + char pad4[15]; +}; + +/* + * Structure of the registers for the "control" display adaptor. + */ +#define PAD(x) char x[12] + +struct preg { /* padded register */ + unsigned r; + char pad[12]; +}; + +struct control_regs { + struct preg vcount; /* vertical counter */ + /* Vertical parameters are in units of 1/2 scan line */ + struct preg vswin; /* between vsblank and vssync */ + struct preg vsblank; /* vert start blank */ + struct preg veblank; /* vert end blank (display start) */ + struct preg vewin; /* between vesync and veblank */ + struct preg vesync; /* vert end sync */ + struct preg vssync; /* vert start sync */ + struct preg vperiod; /* vert period */ + struct preg piped; /* pipe delay hardware cursor */ + /* Horizontal params are in units of 2 pixels */ + struct preg hperiod; /* horiz period - 2 */ + struct preg hsblank; /* horiz start blank */ + struct preg heblank; /* horiz end blank */ + struct preg hesync; /* horiz end sync */ + struct preg hssync; /* horiz start sync */ + struct preg heq; /* half horiz sync len */ + struct preg hlfln; /* half horiz period */ + struct preg hserr; /* horiz period - horiz sync len */ + struct preg cnttst; + struct preg ctrl; /* display control */ + struct preg start_addr; /* start address: 5 lsbs zero */ + struct preg pitch; /* addrs diff between scan lines */ + struct preg mon_sense; /* monitor sense bits */ + struct preg vram_attr; /* enable vram banks */ + struct preg mode; + struct preg rfrcnt; /* refresh count */ + struct preg intr_ena; /* interrupt enable */ + struct preg intr_stat; /* interrupt status */ + struct preg res[5]; +}; + +struct control_regints { + /* Vertical parameters are in units of 1/2 scan line */ + unsigned vswin; /* between vsblank and vssync */ + unsigned vsblank; /* vert start blank */ + unsigned veblank; /* vert end blank (display start) */ + unsigned vewin; /* between vesync and veblank */ + unsigned vesync; /* vert end sync */ + unsigned vssync; /* vert start sync */ + unsigned vperiod; /* vert period */ + unsigned piped; /* pipe delay hardware cursor */ + /* Horizontal params are in units of 2 pixels */ + /* Except, apparently, for hres > 1024 (or == 1280?) */ + unsigned hperiod; /* horiz period - 2 */ + unsigned hsblank; /* horiz start blank */ + unsigned heblank; /* horiz end blank */ + unsigned hesync; /* horiz end sync */ + unsigned hssync; /* horiz start sync */ + unsigned heq; /* half horiz sync len */ + unsigned hlfln; /* half horiz period */ + unsigned hserr; /* horiz period - horiz sync len */ +}; + +/* + * Dot clock rate is + * 3.9064MHz * 2**clock_params[2] * clock_params[1] / clock_params[0]. + */ +struct control_regvals { + unsigned regs[16]; /* for vswin .. hserr */ + unsigned char mode; + unsigned char radacal_ctrl; + unsigned char clock_params[3]; +}; + +#define CTRLFB_OFF 16 /* position of pixel 0 in frame buffer */ + + +/* + * Best cmode supported by control + */ +struct max_cmodes { + int m[2]; /* 0: 2MB vram, 1: 4MB vram */ +}; + +/* + * Video modes supported by macmodes.c + */ +static struct max_cmodes control_mac_modes[] = { + {{-1,-1}}, /* 512x384, 60Hz interlaced (NTSC) */ + {{-1,-1}}, /* 512x384, 60Hz */ + {{-1,-1}}, /* 640x480, 50Hz interlaced (PAL) */ + {{-1,-1}}, /* 640x480, 60Hz interlaced (NTSC) */ + {{ 2, 2}}, /* 640x480, 60Hz (VGA) */ + {{ 2, 2}}, /* 640x480, 67Hz */ + {{-1,-1}}, /* 640x870, 75Hz (portrait) */ + {{-1,-1}}, /* 768x576, 50Hz (PAL full frame) */ + {{ 2, 2}}, /* 800x600, 56Hz */ + {{ 2, 2}}, /* 800x600, 60Hz */ + {{ 2, 2}}, /* 800x600, 72Hz */ + {{ 2, 2}}, /* 800x600, 75Hz */ + {{ 1, 2}}, /* 832x624, 75Hz */ + {{ 1, 2}}, /* 1024x768, 60Hz */ + {{ 1, 2}}, /* 1024x768, 70Hz (or 72Hz?) */ + {{ 1, 2}}, /* 1024x768, 75Hz (VESA) */ + {{ 1, 2}}, /* 1024x768, 75Hz */ + {{ 1, 2}}, /* 1152x870, 75Hz */ + {{ 0, 1}}, /* 1280x960, 75Hz */ + {{ 0, 1}}, /* 1280x1024, 75Hz */ + {{ 1, 2}}, /* 1152x768, 60Hz */ + {{ 0, 1}}, /* 1600x1024, 60Hz */ +}; + -- cgit v1.3.1