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/wireguard/generated/netlink.c | 73 +++++++++++++++++++++++++++++++ drivers/net/wireguard/generated/netlink.h | 30 +++++++++++++ 2 files changed, 103 insertions(+) create mode 100644 drivers/net/wireguard/generated/netlink.c create mode 100644 drivers/net/wireguard/generated/netlink.h (limited to 'drivers/net/wireguard/generated') diff --git a/drivers/net/wireguard/generated/netlink.c b/drivers/net/wireguard/generated/netlink.c new file mode 100644 index 000000000..3ef8c2990 --- /dev/null +++ b/drivers/net/wireguard/generated/netlink.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/wireguard.yaml */ +/* YNL-GEN kernel source */ +/* YNL-ARG --function-prefix wg */ +/* To regenerate run: tools/net/ynl/ynl-regen.sh */ + +#include +#include + +#include "netlink.h" + +#include +#include + +/* Common nested types */ +const struct nla_policy wireguard_wgallowedip_nl_policy[WGALLOWEDIP_A_FLAGS + 1] = { + [WGALLOWEDIP_A_FAMILY] = { .type = NLA_U16, }, + [WGALLOWEDIP_A_IPADDR] = NLA_POLICY_MIN_LEN(4), + [WGALLOWEDIP_A_CIDR_MASK] = { .type = NLA_U8, }, + [WGALLOWEDIP_A_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0x1), +}; + +const struct nla_policy wireguard_wgpeer_nl_policy[WGPEER_A_PROTOCOL_VERSION + 1] = { + [WGPEER_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(WG_KEY_LEN), + [WGPEER_A_PRESHARED_KEY] = NLA_POLICY_EXACT_LEN(WG_KEY_LEN), + [WGPEER_A_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0x7), + [WGPEER_A_ENDPOINT] = NLA_POLICY_MIN_LEN(16), + [WGPEER_A_PERSISTENT_KEEPALIVE_INTERVAL] = { .type = NLA_U16, }, + [WGPEER_A_LAST_HANDSHAKE_TIME] = NLA_POLICY_EXACT_LEN(16), + [WGPEER_A_RX_BYTES] = { .type = NLA_U64, }, + [WGPEER_A_TX_BYTES] = { .type = NLA_U64, }, + [WGPEER_A_ALLOWEDIPS] = NLA_POLICY_NESTED_ARRAY(wireguard_wgallowedip_nl_policy), + [WGPEER_A_PROTOCOL_VERSION] = { .type = NLA_U32, }, +}; + +/* WG_CMD_GET_DEVICE - dump */ +static const struct nla_policy wireguard_get_device_nl_policy[WGDEVICE_A_IFNAME + 1] = { + [WGDEVICE_A_IFINDEX] = { .type = NLA_U32, }, + [WGDEVICE_A_IFNAME] = { .type = NLA_NUL_STRING, .len = 15, }, +}; + +/* WG_CMD_SET_DEVICE - do */ +static const struct nla_policy wireguard_set_device_nl_policy[WGDEVICE_A_PEERS + 1] = { + [WGDEVICE_A_IFINDEX] = { .type = NLA_U32, }, + [WGDEVICE_A_IFNAME] = { .type = NLA_NUL_STRING, .len = 15, }, + [WGDEVICE_A_PRIVATE_KEY] = NLA_POLICY_EXACT_LEN(WG_KEY_LEN), + [WGDEVICE_A_PUBLIC_KEY] = NLA_POLICY_EXACT_LEN(WG_KEY_LEN), + [WGDEVICE_A_FLAGS] = NLA_POLICY_MASK(NLA_U32, 0x1), + [WGDEVICE_A_LISTEN_PORT] = { .type = NLA_U16, }, + [WGDEVICE_A_FWMARK] = { .type = NLA_U32, }, + [WGDEVICE_A_PEERS] = NLA_POLICY_NESTED_ARRAY(wireguard_wgpeer_nl_policy), +}; + +/* Ops table for wireguard */ +const struct genl_split_ops wireguard_nl_ops[2] = { + { + .cmd = WG_CMD_GET_DEVICE, + .start = wg_get_device_start, + .dumpit = wg_get_device_dumpit, + .done = wg_get_device_done, + .policy = wireguard_get_device_nl_policy, + .maxattr = WGDEVICE_A_IFNAME, + .flags = GENL_UNS_ADMIN_PERM | GENL_CMD_CAP_DUMP, + }, + { + .cmd = WG_CMD_SET_DEVICE, + .doit = wg_set_device_doit, + .policy = wireguard_set_device_nl_policy, + .maxattr = WGDEVICE_A_PEERS, + .flags = GENL_UNS_ADMIN_PERM | GENL_CMD_CAP_DO, + }, +}; diff --git a/drivers/net/wireguard/generated/netlink.h b/drivers/net/wireguard/generated/netlink.h new file mode 100644 index 000000000..5dc977ee9 --- /dev/null +++ b/drivers/net/wireguard/generated/netlink.h @@ -0,0 +1,30 @@ +/* SPDX-License-Identifier: ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) */ +/* Do not edit directly, auto-generated from: */ +/* Documentation/netlink/specs/wireguard.yaml */ +/* YNL-GEN kernel header */ +/* YNL-ARG --function-prefix wg */ +/* To regenerate run: tools/net/ynl/ynl-regen.sh */ + +#ifndef _LINUX_WIREGUARD_GEN_H +#define _LINUX_WIREGUARD_GEN_H + +#include +#include + +#include +#include + +/* Common nested types */ +extern const struct nla_policy wireguard_wgallowedip_nl_policy[WGALLOWEDIP_A_FLAGS + 1]; +extern const struct nla_policy wireguard_wgpeer_nl_policy[WGPEER_A_PROTOCOL_VERSION + 1]; + +/* Ops table for wireguard */ +extern const struct genl_split_ops wireguard_nl_ops[2]; + +int wg_get_device_start(struct netlink_callback *cb); +int wg_get_device_done(struct netlink_callback *cb); + +int wg_get_device_dumpit(struct sk_buff *skb, struct netlink_callback *cb); +int wg_set_device_doit(struct sk_buff *skb, struct genl_info *info); + +#endif /* _LINUX_WIREGUARD_GEN_H */ -- cgit v1.3.1