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 --- arch/alpha/boot/Makefile | 120 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 120 insertions(+) create mode 100644 arch/alpha/boot/Makefile (limited to 'arch/alpha/boot/Makefile') diff --git a/arch/alpha/boot/Makefile b/arch/alpha/boot/Makefile new file mode 100644 index 000000000..d8dba85e6 --- /dev/null +++ b/arch/alpha/boot/Makefile @@ -0,0 +1,120 @@ +# +# arch/alpha/boot/Makefile +# +# 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. +# +# Copyright (C) 1994 by Linus Torvalds +# + +hostprogs := tools/mkbb tools/objstrip +targets := vmlinux.gz vmlinux \ + vmlinux.nh tools/lxboot tools/bootlx tools/bootph \ + tools/bootpzh bootloader bootpheader bootpzheader +OBJSTRIP := $(obj)/tools/objstrip + +KBUILD_HOSTCFLAGS := -Wall -I$(objtree)/usr/include +BOOTCFLAGS += -I$(objtree)/$(obj) -I$(srctree)/$(obj) + +# SRM bootable image. Copy to offset 512 of a partition. +$(obj)/bootimage: $(addprefix $(obj)/tools/,mkbb lxboot bootlx) $(obj)/vmlinux.nh + ( cat $(obj)/tools/lxboot $(obj)/tools/bootlx $(obj)/vmlinux.nh ) > $@ + $(obj)/tools/mkbb $@ $(obj)/tools/lxboot + @echo ' Bootimage $@ is ready' + +# BOOTP bootable image. Define INITRD during make to append initrd image. +$(obj)/bootpfile: $(obj)/tools/bootph $(obj)/vmlinux.nh + cat $(obj)/tools/bootph $(obj)/vmlinux.nh > $@ +ifdef INITRD + cat $(INITRD) >> $@ +endif + +# Compressed kernel BOOTP bootable image. +# Define INITRD during make to append initrd image. +$(obj)/bootpzfile: $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz + cat $(obj)/tools/bootpzh $(obj)/vmlinux.nh.gz > $@ +ifdef INITRD + cat $(INITRD) >> $@ +endif + +# Compressed kernel image +$(obj)/vmlinux.gz: $(obj)/vmlinux FORCE + $(call if_changed,gzip) + @echo ' Kernel $@ is ready' + +$(obj)/main.o: $(obj)/ksize.h +$(obj)/bootp.o: $(obj)/ksize.h +$(obj)/bootpz.o: $(obj)/kzsize.h + +$(obj)/ksize.h: $(obj)/vmlinux.nh FORCE + echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T +ifdef INITRD + [ -f $(INITRD) ] || exit 1 + echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T +endif + cmp -s $@T $@ || mv -f $@T $@ + rm -f $@T + +$(obj)/kzsize.h: $(obj)/vmlinux.nh.gz FORCE + echo "#define KERNEL_SIZE `ls -l $(obj)/vmlinux.nh | awk '{print $$5}'`" > $@T + echo "#define KERNEL_Z_SIZE `ls -l $(obj)/vmlinux.nh.gz | awk '{print $$5}'`" >> $@T +ifdef INITRD + [ -f $(INITRD) ] || exit 1 + echo "#define INITRD_IMAGE_SIZE `ls -l $(INITRD) | awk '{print $$5}'`" >> $@T +endif + cmp -s $@T $@ || mv -f $@T $@ + rm -f $@T + +quiet_cmd_strip = STRIP $@ + cmd_strip = $(STRIP) -o $@ $< + +$(obj)/vmlinux: vmlinux FORCE + $(call if_changed,strip) + +quiet_cmd_objstrip = OBJSTRIP $@ + cmd_objstrip = $(OBJSTRIP) $(OSFLAGS_$(@F)) $< $@ + +OSFLAGS_vmlinux.nh := -v +OSFLAGS_lxboot := -p +OSFLAGS_bootlx := -vb +OSFLAGS_bootph := -vb +OSFLAGS_bootpzh := -vb + +$(obj)/vmlinux.nh: vmlinux $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/vmlinux.nh.gz: $(obj)/vmlinux.nh FORCE + $(call if_changed,gzip) + +$(obj)/tools/lxboot: $(obj)/bootloader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootlx: $(obj)/bootloader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootph: $(obj)/bootpheader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +$(obj)/tools/bootpzh: $(obj)/bootpzheader $(OBJSTRIP) FORCE + $(call if_changed,objstrip) + +LDFLAGS_bootloader := -static -T # -N -relax +LDFLAGS_bootloader := -static -T # -N -relax +LDFLAGS_bootpheader := -static -T # -N -relax +LDFLAGS_bootpzheader := -static -T # -N -relax + +OBJ_bootlx := $(obj)/head.o $(obj)/stdio.o $(obj)/main.o +OBJ_bootph := $(obj)/head.o $(obj)/stdio.o $(obj)/bootp.o +OBJ_bootpzh := $(obj)/head.o $(obj)/stdio.o $(obj)/bootpz.o $(obj)/misc.o + +$(obj)/bootloader: $(obj)/bootloader.lds $(OBJ_bootlx) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/bootpheader: $(obj)/bootloader.lds $(OBJ_bootph) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/bootpzheader: $(obj)/bootloader.lds $(OBJ_bootpzh) $(LIBS_Y) FORCE + $(call if_changed,ld) + +$(obj)/misc.o: lib/inflate.c -- cgit v1.3.1