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 --- tools/testing/nvdimm/Kbuild | 87 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 87 insertions(+) create mode 100644 tools/testing/nvdimm/Kbuild (limited to 'tools/testing/nvdimm/Kbuild') diff --git a/tools/testing/nvdimm/Kbuild b/tools/testing/nvdimm/Kbuild new file mode 100644 index 000000000..91a3627f3 --- /dev/null +++ b/tools/testing/nvdimm/Kbuild @@ -0,0 +1,87 @@ +# SPDX-License-Identifier: GPL-2.0 +ldflags-y += --wrap=ioremap_wc +ldflags-y += --wrap=memremap +ldflags-y += --wrap=devm_ioremap +ldflags-y += --wrap=devm_memremap +ldflags-y += --wrap=devm_memunmap +ldflags-y += --wrap=ioremap +ldflags-y += --wrap=iounmap +ldflags-y += --wrap=memunmap +ldflags-y += --wrap=__devm_request_region +ldflags-y += --wrap=__devm_release_region +ldflags-y += --wrap=__request_region +ldflags-y += --wrap=__release_region +ldflags-y += --wrap=devm_memremap_pages +ldflags-y += --wrap=insert_resource +ldflags-y += --wrap=remove_resource +ldflags-y += --wrap=acpi_evaluate_object +ldflags-y += --wrap=acpi_evaluate_dsm + +DRIVERS := ../../../drivers +NVDIMM_SRC := $(DRIVERS)/nvdimm +ACPI_SRC := $(DRIVERS)/acpi/nfit +DAX_SRC := $(DRIVERS)/dax +ccflags-y := -I$(srctree)/drivers/nvdimm/ +ccflags-y += -I$(srctree)/drivers/acpi/nfit/ + +obj-$(CONFIG_LIBNVDIMM) += libnvdimm.o +obj-$(CONFIG_BLK_DEV_PMEM) += nd_pmem.o +obj-$(CONFIG_ND_BTT) += nd_btt.o +obj-$(CONFIG_X86_PMEM_LEGACY) += nd_e820.o +obj-$(CONFIG_ACPI_NFIT) += nfit.o +ifeq ($(CONFIG_DAX),m) +obj-$(CONFIG_DAX) += dax.o +endif +obj-$(CONFIG_DEV_DAX) += device_dax.o +obj-$(CONFIG_DEV_DAX_PMEM) += dax_pmem.o + +nfit-y := $(ACPI_SRC)/core.o +nfit-y += $(ACPI_SRC)/intel.o +nfit-$(CONFIG_X86_MCE) += $(ACPI_SRC)/mce.o +nfit-y += acpi_nfit_test.o +nfit-y += config_check.o + +nd_pmem-y := $(NVDIMM_SRC)/pmem.o +nd_pmem-y += pmem-dax.o +nd_pmem-y += pmem_test.o +nd_pmem-y += config_check.o + +nd_btt-y := $(NVDIMM_SRC)/btt.o +nd_btt-y += config_check.o + +nd_e820-y := $(NVDIMM_SRC)/e820.o +nd_e820-y += config_check.o + +dax-y := $(DAX_SRC)/super.o +dax-y += $(DAX_SRC)/bus.o +dax-y += config_check.o + +device_dax-y := $(DAX_SRC)/device.o +device_dax-y += dax-dev.o +device_dax-y += device_dax_test.o +device_dax-y += config_check.o + +dax_pmem-y := $(DAX_SRC)/pmem.o +dax_pmem-y += dax_pmem_test.o +dax_pmem-y += config_check.o + +libnvdimm-y := $(NVDIMM_SRC)/core.o +libnvdimm-y += $(NVDIMM_SRC)/bus.o +libnvdimm-y += $(NVDIMM_SRC)/dimm_devs.o +libnvdimm-y += $(NVDIMM_SRC)/dimm.o +libnvdimm-y += $(NVDIMM_SRC)/region_devs.o +libnvdimm-y += $(NVDIMM_SRC)/region.o +libnvdimm-y += $(NVDIMM_SRC)/namespace_devs.o +libnvdimm-y += $(NVDIMM_SRC)/label.o +libnvdimm-y += $(NVDIMM_SRC)/badrange.o +libnvdimm-$(CONFIG_ND_CLAIM) += $(NVDIMM_SRC)/claim.o +libnvdimm-$(CONFIG_BTT) += $(NVDIMM_SRC)/btt_devs.o +libnvdimm-$(CONFIG_NVDIMM_PFN) += $(NVDIMM_SRC)/pfn_devs.o +libnvdimm-$(CONFIG_NVDIMM_DAX) += $(NVDIMM_SRC)/dax_devs.o +libnvdimm-$(CONFIG_NVDIMM_KEYS) += $(NVDIMM_SRC)/security.o +libnvdimm-y += libnvdimm_test.o +libnvdimm-y += config_check.o + +KBUILD_CFLAGS := $(filter-out -Wmissing-prototypes -Wmissing-declarations, $(KBUILD_CFLAGS)) + +obj-m += test/ -- cgit v1.3.1