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 --- sound/soc/sof/sof-client-probes.h | 72 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) create mode 100644 sound/soc/sof/sof-client-probes.h (limited to 'sound/soc/sof/sof-client-probes.h') diff --git a/sound/soc/sof/sof-client-probes.h b/sound/soc/sof/sof-client-probes.h new file mode 100644 index 000000000..47d0582b8 --- /dev/null +++ b/sound/soc/sof/sof-client-probes.h @@ -0,0 +1,72 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#ifndef __SOF_CLIENT_PROBES_H +#define __SOF_CLIENT_PROBES_H + +struct snd_compr_stream; +struct snd_compr_tstamp64; +struct snd_compr_params; +struct sof_client_dev; +struct snd_soc_dai; + +/* + * Callbacks used on platforms where the control for audio is split between + * DSP and host, like HDA. + */ +struct sof_probes_host_ops { + int (*startup)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream, + struct snd_soc_dai *dai, u32 *stream_id); + int (*shutdown)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream, + struct snd_soc_dai *dai); + int (*set_params)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream, + struct snd_compr_params *params, + struct snd_soc_dai *dai); + int (*trigger)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream, + int cmd, struct snd_soc_dai *dai); + int (*pointer)(struct sof_client_dev *cdev, struct snd_compr_stream *cstream, + struct snd_compr_tstamp64 *tstamp, + struct snd_soc_dai *dai); +}; + +struct sof_probe_point_desc { + unsigned int buffer_id; + unsigned int purpose; + unsigned int stream_tag; +} __packed; + +enum sof_probe_info_type { + PROBES_INFO_ACTIVE_PROBES, + PROBES_INFO_AVAILABE_PROBES, +}; + +struct sof_probes_ipc_ops { + int (*init)(struct sof_client_dev *cdev, u32 stream_tag, + size_t buffer_size); + int (*deinit)(struct sof_client_dev *cdev); + int (*points_info)(struct sof_client_dev *cdev, + struct sof_probe_point_desc **desc, + size_t *num_desc, enum sof_probe_info_type type); + int (*point_print)(struct sof_client_dev *cdev, char *buf, size_t size, + struct sof_probe_point_desc *desc); + int (*points_add)(struct sof_client_dev *cdev, + struct sof_probe_point_desc *desc, + size_t num_desc); + int (*points_remove)(struct sof_client_dev *cdev, + unsigned int *buffer_id, size_t num_buffer_id); +}; + +extern const struct sof_probes_ipc_ops ipc3_probe_ops; +extern const struct sof_probes_ipc_ops ipc4_probe_ops; + +struct sof_probes_priv { + struct dentry *dfs_points; + struct dentry *dfs_points_remove; + u32 extractor_stream_tag; + struct snd_soc_card card; + void *ipc_priv; + + const struct sof_probes_host_ops *host_ops; + const struct sof_probes_ipc_ops *ipc_ops; +}; + +#endif -- cgit v1.3.1