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/openvswitch/openvswitch_trace.h | 158 ++++++++++++++++++++++++++++++++++++ 1 file changed, 158 insertions(+) create mode 100644 net/openvswitch/openvswitch_trace.h (limited to 'net/openvswitch/openvswitch_trace.h') diff --git a/net/openvswitch/openvswitch_trace.h b/net/openvswitch/openvswitch_trace.h new file mode 100644 index 000000000..74d75aaeb --- /dev/null +++ b/net/openvswitch/openvswitch_trace.h @@ -0,0 +1,158 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM openvswitch + +#if !defined(_TRACE_OPENVSWITCH_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_OPENVSWITCH_H + +#include + +#include "datapath.h" + +TRACE_EVENT(ovs_do_execute_action, + + TP_PROTO(struct datapath *dp, struct sk_buff *skb, + struct sw_flow_key *key, const struct nlattr *a, int rem), + + TP_ARGS(dp, skb, key, a, rem), + + TP_STRUCT__entry( + __field( void *, dpaddr ) + __string( dp_name, ovs_dp_name(dp) ) + __string( dev_name, skb->dev->name ) + __field( void *, skbaddr ) + __field( unsigned int, len ) + __field( unsigned int, data_len ) + __field( unsigned int, truesize ) + __field( u8, nr_frags ) + __field( u16, gso_size ) + __field( u16, gso_type ) + __field( u32, ovs_flow_hash ) + __field( u32, recirc_id ) + __field( void *, keyaddr ) + __field( u16, key_eth_type ) + __field( u8, key_ct_state ) + __field( u8, key_ct_orig_proto ) + __field( u16, key_ct_zone ) + __field( unsigned int, flow_key_valid ) + __field( u8, action_type ) + __field( unsigned int, action_len ) + __field( void *, action_data ) + __field( u8, is_last ) + ), + + TP_fast_assign( + __entry->dpaddr = dp; + __assign_str(dp_name); + __assign_str(dev_name); + __entry->skbaddr = skb; + __entry->len = skb->len; + __entry->data_len = skb->data_len; + __entry->truesize = skb->truesize; + __entry->nr_frags = skb_shinfo(skb)->nr_frags; + __entry->gso_size = skb_shinfo(skb)->gso_size; + __entry->gso_type = skb_shinfo(skb)->gso_type; + __entry->ovs_flow_hash = key->ovs_flow_hash; + __entry->recirc_id = key->recirc_id; + __entry->keyaddr = key; + __entry->key_eth_type = key->eth.type; + __entry->key_ct_state = key->ct_state; + __entry->key_ct_orig_proto = key->ct_orig_proto; + __entry->key_ct_zone = key->ct_zone; + __entry->flow_key_valid = !(key->mac_proto & SW_FLOW_KEY_INVALID); + __entry->action_type = nla_type(a); + __entry->action_len = nla_len(a); + __entry->action_data = nla_data(a); + __entry->is_last = nla_is_last(a, rem); + ), + + TP_printk("dpaddr=%p dp_name=%s dev=%s skbaddr=%p len=%u data_len=%u truesize=%u nr_frags=%d gso_size=%d gso_type=%#x ovs_flow_hash=0x%08x recirc_id=0x%08x keyaddr=%p eth_type=0x%04x ct_state=%02x ct_orig_proto=%02x ct_Zone=%04x flow_key_valid=%d action_type=%u action_len=%u action_data=%p is_last=%d", + __entry->dpaddr, __get_str(dp_name), __get_str(dev_name), + __entry->skbaddr, __entry->len, __entry->data_len, + __entry->truesize, __entry->nr_frags, __entry->gso_size, + __entry->gso_type, __entry->ovs_flow_hash, + __entry->recirc_id, __entry->keyaddr, __entry->key_eth_type, + __entry->key_ct_state, __entry->key_ct_orig_proto, + __entry->key_ct_zone, + __entry->flow_key_valid, + __entry->action_type, __entry->action_len, + __entry->action_data, __entry->is_last) +); + +TRACE_EVENT(ovs_dp_upcall, + + TP_PROTO(struct datapath *dp, struct sk_buff *skb, + const struct sw_flow_key *key, + const struct dp_upcall_info *upcall_info), + + TP_ARGS(dp, skb, key, upcall_info), + + TP_STRUCT__entry( + __field( void *, dpaddr ) + __string( dp_name, ovs_dp_name(dp) ) + __string( dev_name, skb->dev->name ) + __field( void *, skbaddr ) + __field( unsigned int, len ) + __field( unsigned int, data_len ) + __field( unsigned int, truesize ) + __field( u8, nr_frags ) + __field( u16, gso_size ) + __field( u16, gso_type ) + __field( u32, ovs_flow_hash ) + __field( u32, recirc_id ) + __field( const void *, keyaddr ) + __field( u16, key_eth_type ) + __field( u8, key_ct_state ) + __field( u8, key_ct_orig_proto ) + __field( u16, key_ct_zone ) + __field( unsigned int, flow_key_valid ) + __field( u8, upcall_cmd ) + __field( u32, upcall_port ) + __field( u16, upcall_mru ) + ), + + TP_fast_assign( + __entry->dpaddr = dp; + __assign_str(dp_name); + __assign_str(dev_name); + __entry->skbaddr = skb; + __entry->len = skb->len; + __entry->data_len = skb->data_len; + __entry->truesize = skb->truesize; + __entry->nr_frags = skb_shinfo(skb)->nr_frags; + __entry->gso_size = skb_shinfo(skb)->gso_size; + __entry->gso_type = skb_shinfo(skb)->gso_type; + __entry->ovs_flow_hash = key->ovs_flow_hash; + __entry->recirc_id = key->recirc_id; + __entry->keyaddr = key; + __entry->key_eth_type = key->eth.type; + __entry->key_ct_state = key->ct_state; + __entry->key_ct_orig_proto = key->ct_orig_proto; + __entry->key_ct_zone = key->ct_zone; + __entry->flow_key_valid = !(key->mac_proto & SW_FLOW_KEY_INVALID); + __entry->upcall_cmd = upcall_info->cmd; + __entry->upcall_port = upcall_info->portid; + __entry->upcall_mru = upcall_info->mru; + ), + + TP_printk("dpaddr=%p dp_name=%s dev=%s skbaddr=%p len=%u data_len=%u truesize=%u nr_frags=%d gso_size=%d gso_type=%#x ovs_flow_hash=0x%08x recirc_id=0x%08x keyaddr=%p eth_type=0x%04x ct_state=%02x ct_orig_proto=%02x ct_zone=%04x flow_key_valid=%d upcall_cmd=%u upcall_port=%u upcall_mru=%u", + __entry->dpaddr, __get_str(dp_name), __get_str(dev_name), + __entry->skbaddr, __entry->len, __entry->data_len, + __entry->truesize, __entry->nr_frags, __entry->gso_size, + __entry->gso_type, __entry->ovs_flow_hash, + __entry->recirc_id, __entry->keyaddr, __entry->key_eth_type, + __entry->key_ct_state, __entry->key_ct_orig_proto, + __entry->key_ct_zone, + __entry->flow_key_valid, + __entry->upcall_cmd, __entry->upcall_port, + __entry->upcall_mru) +); + +#endif /* _TRACE_OPENVSWITCH_H */ + +/* This part must be outside protection */ +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE openvswitch_trace +#include -- cgit v1.3.1