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/stream-ipc.c | 131 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 sound/soc/sof/stream-ipc.c (limited to 'sound/soc/sof/stream-ipc.c') diff --git a/sound/soc/sof/stream-ipc.c b/sound/soc/sof/stream-ipc.c new file mode 100644 index 000000000..78758cf58 --- /dev/null +++ b/sound/soc/sof/stream-ipc.c @@ -0,0 +1,131 @@ +// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) +// +// This file is provided under a dual BSD/GPLv2 license. When using or +// redistributing this file, you may do so under either license. +// +// Copyright(c) 2019 Intel Corporation +// +// Authors: Guennadi Liakhovetski + +/* Generic SOF IPC code */ + +#include +#include +#include +#include + +#include +#include + +#include "ops.h" +#include "sof-priv.h" +#include "sof-audio.h" + +struct sof_stream { + size_t posn_offset; +}; + +/* Mailbox-based Generic IPC implementation */ +int sof_ipc_msg_data(struct snd_sof_dev *sdev, + struct snd_sof_pcm_stream *sps, + void *p, size_t sz) +{ + if (!sps || !sdev->stream_box.size) { + snd_sof_dsp_mailbox_read(sdev, sdev->dsp_box.offset, p, sz); + } else { + size_t posn_offset; + + if (sps->substream) { + struct sof_stream *stream = sps->substream->runtime->private_data; + + /* The stream might already be closed */ + if (!stream) + return -ESTRPIPE; + + posn_offset = stream->posn_offset; + } else if (sps->cstream) { + + struct sof_compr_stream *sstream = sps->cstream->runtime->private_data; + + if (!sstream) + return -ESTRPIPE; + + posn_offset = sstream->posn_offset; + + } else { + dev_err(sdev->dev, "%s: No stream opened\n", __func__); + return -EINVAL; + } + + snd_sof_dsp_mailbox_read(sdev, posn_offset, p, sz); + } + + return 0; +} +EXPORT_SYMBOL(sof_ipc_msg_data); + +int sof_set_stream_data_offset(struct snd_sof_dev *sdev, + struct snd_sof_pcm_stream *sps, + size_t posn_offset) +{ + /* check if offset is overflow or it is not aligned */ + if (posn_offset > sdev->stream_box.size || + posn_offset % sizeof(struct sof_ipc_stream_posn) != 0) + return -EINVAL; + + posn_offset += sdev->stream_box.offset; + + if (sps->substream) { + struct sof_stream *stream = sps->substream->runtime->private_data; + + stream->posn_offset = posn_offset; + dev_dbg(sdev->dev, "pcm: stream dir %d, posn mailbox offset is %zu", + sps->substream->stream, posn_offset); + } else if (sps->cstream) { + struct sof_compr_stream *sstream = sps->cstream->runtime->private_data; + + sstream->posn_offset = posn_offset; + dev_dbg(sdev->dev, "compr: stream dir %d, posn mailbox offset is %zu", + sps->cstream->direction, posn_offset); + } else { + dev_err(sdev->dev, "No stream opened"); + return -EINVAL; + } + + return 0; +} +EXPORT_SYMBOL(sof_set_stream_data_offset); + +int sof_stream_pcm_open(struct snd_sof_dev *sdev, + struct snd_pcm_substream *substream) +{ + struct sof_stream *stream = kmalloc_obj(*stream); + + if (!stream) + return -ENOMEM; + + /* binding pcm substream to hda stream */ + substream->runtime->private_data = stream; + + /* align to DMA minimum transfer size */ + snd_pcm_hw_constraint_step(substream->runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 4); + + /* avoid circular buffer wrap in middle of period */ + snd_pcm_hw_constraint_integer(substream->runtime, + SNDRV_PCM_HW_PARAM_PERIODS); + + return 0; +} +EXPORT_SYMBOL(sof_stream_pcm_open); + +int sof_stream_pcm_close(struct snd_sof_dev *sdev, + struct snd_pcm_substream *substream) +{ + struct sof_stream *stream = substream->runtime->private_data; + + substream->runtime->private_data = NULL; + kfree(stream); + + return 0; +} +EXPORT_SYMBOL(sof_stream_pcm_close); -- cgit v1.3.1