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/Makefile | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 88 insertions(+) create mode 100644 drivers/net/Makefile (limited to 'drivers/net/Makefile') diff --git a/drivers/net/Makefile b/drivers/net/Makefile new file mode 100644 index 000000000..88e4c485d --- /dev/null +++ b/drivers/net/Makefile @@ -0,0 +1,88 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the Linux network device drivers. +# + +# +# Networking Core Drivers +# +obj-$(CONFIG_BONDING) += bonding/ +obj-$(CONFIG_IPVLAN) += ipvlan/ +obj-$(CONFIG_IPVTAP) += ipvlan/ +obj-$(CONFIG_DUMMY) += dummy.o +obj-$(CONFIG_WIREGUARD) += wireguard/ +obj-$(CONFIG_OVPN) += ovpn/ +obj-$(CONFIG_EQUALIZER) += eql.o +obj-$(CONFIG_IFB) += ifb.o +obj-$(CONFIG_MACSEC) += macsec.o +obj-$(CONFIG_AMT) += amt.o +obj-$(CONFIG_MACVLAN) += macvlan.o +obj-$(CONFIG_MACVTAP) += macvtap.o +obj-$(CONFIG_MII) += mii.o +obj-$(CONFIG_MDIO) += mdio.o +obj-$(CONFIG_NET) += loopback.o +obj-$(CONFIG_NETCONSOLE) += netconsole.o +obj-$(CONFIG_NETKIT) += netkit.o +obj-y += phy/ +obj-y += pse-pd/ +obj-y += mdio/ +obj-y += pcs/ +obj-$(CONFIG_RIONET) += rionet.o +obj-$(CONFIG_NET_TEAM) += team/ +obj-$(CONFIG_TUN) += tun.o +obj-$(CONFIG_TAP) += tap.o +obj-$(CONFIG_VETH) += veth.o +obj-$(CONFIG_VIRTIO_NET) += virtio_net.o +obj-$(CONFIG_VXLAN) += vxlan/ +obj-$(CONFIG_GENEVE) += geneve.o +obj-$(CONFIG_BAREUDP) += bareudp.o +obj-$(CONFIG_GTP) += gtp.o +obj-$(CONFIG_NLMON) += nlmon.o +obj-$(CONFIG_PFCP) += pfcp.o +obj-$(CONFIG_NET_VRF) += vrf.o +obj-$(CONFIG_VSOCKMON) += vsockmon.o +obj-$(CONFIG_MHI_NET) += mhi_net.o + +# +# Networking Drivers +# +obj-$(CONFIG_ARCNET) += arcnet/ +obj-$(CONFIG_CAN) += can/ +ifdef CONFIG_NET_DSA +obj-y += dsa/ +endif +obj-$(CONFIG_ETHERNET) += ethernet/ +obj-$(CONFIG_FDDI) += fddi/ +obj-$(CONFIG_QCOM_IPA) += ipa/ +obj-$(CONFIG_PLIP) += plip/ +obj-$(CONFIG_PPP) += ppp/ +obj-$(CONFIG_PPP_ASYNC) += ppp/ +obj-$(CONFIG_PPP_BSDCOMP) += ppp/ +obj-$(CONFIG_PPP_DEFLATE) += ppp/ +obj-$(CONFIG_PPP_MPPE) += ppp/ +obj-$(CONFIG_PPP_SYNC_TTY) += ppp/ +obj-$(CONFIG_PPPOE) += ppp/ +obj-$(CONFIG_PPPOL2TP) += ppp/ +obj-$(CONFIG_PPTP) += ppp/ +obj-$(CONFIG_SLIP) += slip/ +obj-$(CONFIG_SLHC) += slip/ +obj-$(CONFIG_SUNGEM_PHY) += sungem_phy.o +obj-$(CONFIG_WAN) += wan/ +obj-$(CONFIG_WLAN) += wireless/ +obj-$(CONFIG_IEEE802154) += ieee802154/ +obj-$(CONFIG_WWAN) += wwan/ +obj-$(CONFIG_MCTP) += mctp/ + +obj-$(CONFIG_VMXNET3) += vmxnet3/ +obj-$(CONFIG_XEN_NETDEV_FRONTEND) += xen-netfront.o +obj-$(CONFIG_XEN_NETDEV_BACKEND) += xen-netback/ + +obj-$(CONFIG_USB_NET_DRIVERS) += usb/ + +obj-$(CONFIG_HYPERV_NET) += hyperv/ +obj-$(CONFIG_NTB_NETDEV) += ntb_netdev.o + +obj-$(CONFIG_FUJITSU_ES) += fjes/ +obj-$(CONFIG_USB4_NET) += thunderbolt/ +obj-$(CONFIG_NETDEVSIM) += netdevsim/ +obj-$(CONFIG_NET_FAILOVER) += net_failover.o -- cgit v1.3.1