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/net/mdio/Makefile | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) create mode 100644 drivers/net/mdio/Makefile (limited to 'drivers/net/mdio/Makefile') diff --git a/drivers/net/mdio/Makefile b/drivers/net/mdio/Makefile new file mode 100644 index 000000000..048586746 --- /dev/null +++ b/drivers/net/mdio/Makefile @@ -0,0 +1,37 @@ +# SPDX-License-Identifier: GPL-2.0 +# Makefile for Linux MDIO bus drivers + +obj-$(CONFIG_ACPI_MDIO) += acpi_mdio.o +obj-$(CONFIG_FWNODE_MDIO) += fwnode_mdio.o +obj-$(CONFIG_OF_MDIO) += of_mdio.o + +obj-$(CONFIG_MDIO_AIROHA) += mdio-airoha.o +obj-$(CONFIG_MDIO_ASPEED) += mdio-aspeed.o +obj-$(CONFIG_MDIO_BCM_IPROC) += mdio-bcm-iproc.o +obj-$(CONFIG_MDIO_BCM_UNIMAC) += mdio-bcm-unimac.o +obj-$(CONFIG_MDIO_BITBANG) += mdio-bitbang.o +obj-$(CONFIG_MDIO_CAVIUM) += mdio-cavium.o +obj-$(CONFIG_MDIO_GPIO) += mdio-gpio.o +obj-$(CONFIG_MDIO_HISI_FEMAC) += mdio-hisi-femac.o +obj-$(CONFIG_MDIO_I2C) += mdio-i2c.o +obj-$(CONFIG_MDIO_IPQ4019) += mdio-ipq4019.o +obj-$(CONFIG_MDIO_IPQ8064) += mdio-ipq8064.o +obj-$(CONFIG_MDIO_MOXART) += mdio-moxart.o +obj-$(CONFIG_MDIO_MSCC_MIIM) += mdio-mscc-miim.o +obj-$(CONFIG_MDIO_MVUSB) += mdio-mvusb.o +obj-$(CONFIG_MDIO_OCTEON) += mdio-octeon.o +obj-$(CONFIG_MDIO_PIC64HPSC) += mdio-pic64hpsc.o +obj-$(CONFIG_MDIO_REALTEK_RTL9300) += mdio-realtek-rtl9300.o +obj-$(CONFIG_MDIO_REGMAP) += mdio-regmap.o +obj-$(CONFIG_MDIO_SUN4I) += mdio-sun4i.o +obj-$(CONFIG_MDIO_THUNDER) += mdio-thunder.o +obj-$(CONFIG_MDIO_XGENE) += mdio-xgene.o + +obj-$(CONFIG_MDIO_BUS_MUX) += mdio-mux.o +obj-$(CONFIG_MDIO_BUS_MUX_BCM6368) += mdio-mux-bcm6368.o +obj-$(CONFIG_MDIO_BUS_MUX_BCM_IPROC) += mdio-mux-bcm-iproc.o +obj-$(CONFIG_MDIO_BUS_MUX_GPIO) += mdio-mux-gpio.o +obj-$(CONFIG_MDIO_BUS_MUX_MESON_G12A) += mdio-mux-meson-g12a.o +obj-$(CONFIG_MDIO_BUS_MUX_MESON_GXL) += mdio-mux-meson-gxl.o +obj-$(CONFIG_MDIO_BUS_MUX_MMIOREG) += mdio-mux-mmioreg.o +obj-$(CONFIG_MDIO_BUS_MUX_MULTIPLEXER) += mdio-mux-multiplexer.o -- cgit v1.3.1