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/thunderbolt/trace.h | 141 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 drivers/net/thunderbolt/trace.h (limited to 'drivers/net/thunderbolt/trace.h') diff --git a/drivers/net/thunderbolt/trace.h b/drivers/net/thunderbolt/trace.h new file mode 100644 index 000000000..9626eadae --- /dev/null +++ b/drivers/net/thunderbolt/trace.h @@ -0,0 +1,141 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Tracepoints for Thunderbolt/USB4 networking driver + * + * Copyright (C) 2023, Intel Corporation + * Author: Mika Westerberg + */ + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM thunderbolt_net + +#if !defined(__TRACE_THUNDERBOLT_NET_H) || defined(TRACE_HEADER_MULTI_READ) +#define __TRACE_THUNDERBOLT_NET_H + +#include +#include +#include + +#define DMA_DATA_DIRECTION_NAMES \ + { DMA_BIDIRECTIONAL, "DMA_BIDIRECTIONAL" }, \ + { DMA_TO_DEVICE, "DMA_TO_DEVICE" }, \ + { DMA_FROM_DEVICE, "DMA_FROM_DEVICE" }, \ + { DMA_NONE, "DMA_NONE" } + +DECLARE_EVENT_CLASS(tbnet_frame, + TP_PROTO(unsigned int index, const void *page, dma_addr_t phys, + enum dma_data_direction dir), + TP_ARGS(index, page, phys, dir), + TP_STRUCT__entry( + __field(unsigned int, index) + __field(const void *, page) + __field(dma_addr_t, phys) + __field(enum dma_data_direction, dir) + ), + TP_fast_assign( + __entry->index = index; + __entry->page = page; + __entry->phys = phys; + __entry->dir = dir; + ), + TP_printk("index=%u page=%p phys=%pad dir=%s", + __entry->index, __entry->page, &__entry->phys, + __print_symbolic(__entry->dir, DMA_DATA_DIRECTION_NAMES)) +); + +DEFINE_EVENT(tbnet_frame, tbnet_alloc_rx_frame, + TP_PROTO(unsigned int index, const void *page, dma_addr_t phys, + enum dma_data_direction dir), + TP_ARGS(index, page, phys, dir) +); + +DEFINE_EVENT(tbnet_frame, tbnet_alloc_tx_frame, + TP_PROTO(unsigned int index, const void *page, dma_addr_t phys, + enum dma_data_direction dir), + TP_ARGS(index, page, phys, dir) +); + +DEFINE_EVENT(tbnet_frame, tbnet_free_frame, + TP_PROTO(unsigned int index, const void *page, dma_addr_t phys, + enum dma_data_direction dir), + TP_ARGS(index, page, phys, dir) +); + +DECLARE_EVENT_CLASS(tbnet_ip_frame, + TP_PROTO(__le32 size, __le16 id, __le16 index, __le32 count), + TP_ARGS(size, id, index, count), + TP_STRUCT__entry( + __field(u32, size) + __field(u16, id) + __field(u16, index) + __field(u32, count) + ), + TP_fast_assign( + __entry->size = le32_to_cpu(size); + __entry->id = le16_to_cpu(id); + __entry->index = le16_to_cpu(index); + __entry->count = le32_to_cpu(count); + ), + TP_printk("id=%u size=%u index=%u count=%u", + __entry->id, __entry->size, __entry->index, __entry->count) +); + +DEFINE_EVENT(tbnet_ip_frame, tbnet_rx_ip_frame, + TP_PROTO(__le32 size, __le16 id, __le16 index, __le32 count), + TP_ARGS(size, id, index, count) +); + +DEFINE_EVENT(tbnet_ip_frame, tbnet_invalid_rx_ip_frame, + TP_PROTO(__le32 size, __le16 id, __le16 index, __le32 count), + TP_ARGS(size, id, index, count) +); + +DEFINE_EVENT(tbnet_ip_frame, tbnet_tx_ip_frame, + TP_PROTO(__le32 size, __le16 id, __le16 index, __le32 count), + TP_ARGS(size, id, index, count) +); + +DECLARE_EVENT_CLASS(tbnet_skb, + TP_PROTO(const struct sk_buff *skb), + TP_ARGS(skb), + TP_STRUCT__entry( + __field(const void *, addr) + __field(unsigned int, len) + __field(unsigned int, data_len) + __field(unsigned int, nr_frags) + ), + TP_fast_assign( + __entry->addr = skb; + __entry->len = skb->len; + __entry->data_len = skb->data_len; + __entry->nr_frags = skb_shinfo(skb)->nr_frags; + ), + TP_printk("skb=%p len=%u data_len=%u nr_frags=%u", + __entry->addr, __entry->len, __entry->data_len, + __entry->nr_frags) +); + +DEFINE_EVENT(tbnet_skb, tbnet_rx_skb, + TP_PROTO(const struct sk_buff *skb), + TP_ARGS(skb) +); + +DEFINE_EVENT(tbnet_skb, tbnet_tx_skb, + TP_PROTO(const struct sk_buff *skb), + TP_ARGS(skb) +); + +DEFINE_EVENT(tbnet_skb, tbnet_consume_skb, + TP_PROTO(const struct sk_buff *skb), + TP_ARGS(skb) +); + +#endif /* _TRACE_THUNDERBOLT_NET_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . + +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE trace + +#include -- cgit v1.3.1