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/pinctrl/intel/Makefile | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) create mode 100644 drivers/pinctrl/intel/Makefile (limited to 'drivers/pinctrl/intel/Makefile') diff --git a/drivers/pinctrl/intel/Makefile b/drivers/pinctrl/intel/Makefile new file mode 100644 index 000000000..d0d868c9a --- /dev/null +++ b/drivers/pinctrl/intel/Makefile @@ -0,0 +1,27 @@ +# SPDX-License-Identifier: GPL-2.0 +# Intel pin control drivers + +obj-$(CONFIG_PINCTRL_BAYTRAIL) += pinctrl-baytrail.o +obj-$(CONFIG_PINCTRL_CHERRYVIEW) += pinctrl-cherryview.o +obj-$(CONFIG_PINCTRL_LYNXPOINT) += pinctrl-lynxpoint.o +obj-$(CONFIG_PINCTRL_TANGIER) += pinctrl-tangier.o +obj-$(CONFIG_PINCTRL_MERRIFIELD) += pinctrl-merrifield.o +obj-$(CONFIG_PINCTRL_MOOREFIELD) += pinctrl-moorefield.o +obj-$(CONFIG_PINCTRL_INTEL) += pinctrl-intel.o +obj-$(CONFIG_PINCTRL_INTEL_PLATFORM) += pinctrl-intel-platform.o +obj-$(CONFIG_PINCTRL_ALDERLAKE) += pinctrl-alderlake.o +obj-$(CONFIG_PINCTRL_BROXTON) += pinctrl-broxton.o +obj-$(CONFIG_PINCTRL_CANNONLAKE) += pinctrl-cannonlake.o +obj-$(CONFIG_PINCTRL_CEDARFORK) += pinctrl-cedarfork.o +obj-$(CONFIG_PINCTRL_DENVERTON) += pinctrl-denverton.o +obj-$(CONFIG_PINCTRL_ELKHARTLAKE) += pinctrl-elkhartlake.o +obj-$(CONFIG_PINCTRL_EMMITSBURG) += pinctrl-emmitsburg.o +obj-$(CONFIG_PINCTRL_GEMINILAKE) += pinctrl-geminilake.o +obj-$(CONFIG_PINCTRL_ICELAKE) += pinctrl-icelake.o +obj-$(CONFIG_PINCTRL_JASPERLAKE) += pinctrl-jasperlake.o +obj-$(CONFIG_PINCTRL_LAKEFIELD) += pinctrl-lakefield.o +obj-$(CONFIG_PINCTRL_LEWISBURG) += pinctrl-lewisburg.o +obj-$(CONFIG_PINCTRL_METEORLAKE) += pinctrl-meteorlake.o +obj-$(CONFIG_PINCTRL_METEORPOINT) += pinctrl-meteorpoint.o +obj-$(CONFIG_PINCTRL_SUNRISEPOINT) += pinctrl-sunrisepoint.o +obj-$(CONFIG_PINCTRL_TIGERLAKE) += pinctrl-tigerlake.o -- cgit v1.3.1