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 --- net/tls/tls_proc.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) create mode 100644 net/tls/tls_proc.c (limited to 'net/tls/tls_proc.c') diff --git a/net/tls/tls_proc.c b/net/tls/tls_proc.c new file mode 100644 index 000000000..4012c4372 --- /dev/null +++ b/net/tls/tls_proc.c @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +/* Copyright (C) 2019 Netronome Systems, Inc. */ + +#include +#include +#include +#include + +#include "tls.h" + +#ifdef CONFIG_PROC_FS +static const struct snmp_mib tls_mib_list[] = { + SNMP_MIB_ITEM("TlsCurrTxSw", LINUX_MIB_TLSCURRTXSW), + SNMP_MIB_ITEM("TlsCurrRxSw", LINUX_MIB_TLSCURRRXSW), + SNMP_MIB_ITEM("TlsCurrTxDevice", LINUX_MIB_TLSCURRTXDEVICE), + SNMP_MIB_ITEM("TlsCurrRxDevice", LINUX_MIB_TLSCURRRXDEVICE), + SNMP_MIB_ITEM("TlsTxSw", LINUX_MIB_TLSTXSW), + SNMP_MIB_ITEM("TlsRxSw", LINUX_MIB_TLSRXSW), + SNMP_MIB_ITEM("TlsTxDevice", LINUX_MIB_TLSTXDEVICE), + SNMP_MIB_ITEM("TlsRxDevice", LINUX_MIB_TLSRXDEVICE), + SNMP_MIB_ITEM("TlsDecryptError", LINUX_MIB_TLSDECRYPTERROR), + SNMP_MIB_ITEM("TlsRxDeviceResync", LINUX_MIB_TLSRXDEVICERESYNC), + SNMP_MIB_ITEM("TlsDecryptRetry", LINUX_MIB_TLSDECRYPTRETRY), + SNMP_MIB_ITEM("TlsRxNoPadViolation", LINUX_MIB_TLSRXNOPADVIOL), + SNMP_MIB_ITEM("TlsRxRekeyOk", LINUX_MIB_TLSRXREKEYOK), + SNMP_MIB_ITEM("TlsRxRekeyError", LINUX_MIB_TLSRXREKEYERROR), + SNMP_MIB_ITEM("TlsTxRekeyOk", LINUX_MIB_TLSTXREKEYOK), + SNMP_MIB_ITEM("TlsTxRekeyError", LINUX_MIB_TLSTXREKEYERROR), + SNMP_MIB_ITEM("TlsRxRekeyReceived", LINUX_MIB_TLSRXREKEYRECEIVED), +}; + +static int tls_statistics_seq_show(struct seq_file *seq, void *v) +{ + unsigned long buf[ARRAY_SIZE(tls_mib_list)]; + const int cnt = ARRAY_SIZE(tls_mib_list); + struct net *net = seq->private; + int i; + + memset(buf, 0, sizeof(buf)); + snmp_get_cpu_field_batch_cnt(buf, tls_mib_list, cnt, + net->mib.tls_statistics); + for (i = 0; i < cnt; i++) + seq_printf(seq, "%-32s\t%lu\n", tls_mib_list[i].name, buf[i]); + + return 0; +} +#endif + +int __net_init tls_proc_init(struct net *net) +{ +#ifdef CONFIG_PROC_FS + if (!proc_create_net_single("tls_stat", 0444, net->proc_net, + tls_statistics_seq_show, NULL)) + return -ENOMEM; +#endif /* CONFIG_PROC_FS */ + + return 0; +} + +void __net_exit tls_proc_fini(struct net *net) +{ + remove_proc_entry("tls_stat", net->proc_net); +} -- cgit v1.3.1