sched/cache: Keep nr_pref_llc_running in the runnable domain, to fix LLC mis-scheduling buggrafted

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 <zhanxusheng@xiaomi.com>
Suggested-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Kayra Cizmeci <kayracizmeci@gmail.com>
Cc: <stable@kernel.org> # v7.2.x
Link: https://patch.msgid.link/06af61afedac32e6477f57feb4d658f6c411c3af.1790035273.git.tim.c.chen@linux.intel.com

1 files changed, 135 insertions, 0 deletions

diff --git a/include/sound/sof/dai.h b/include/sound/sof/dai.h
new file mode 100644
index 000000000..e3fe492e7
--- /dev/null
+++ b/include/sound/sof/dai.h
@@ -0,0 +1,135 @@
+/* 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) 2018 Intel Corporation
+ */
+
+#ifndef __INCLUDE_SOUND_SOF_DAI_H__
+#define __INCLUDE_SOUND_SOF_DAI_H__
+
+#include <sound/sof/header.h>
+#include <sound/sof/dai-intel.h>
+#include <sound/sof/dai-imx.h>
+#include <sound/sof/dai-amd.h>
+#include <sound/sof/dai-mediatek.h>
+
+/*
+ * DAI Configuration.
+ *
+ * Each different DAI type will have it's own structure and IPC cmd.
+ */
+
+#define SOF_DAI_FMT_I2S		1 /**< I2S mode */
+#define SOF_DAI_FMT_RIGHT_J	2 /**< Right Justified mode */
+#define SOF_DAI_FMT_LEFT_J	3 /**< Left Justified mode */
+#define SOF_DAI_FMT_DSP_A	4 /**< L data MSB after FRM LRC */
+#define SOF_DAI_FMT_DSP_B	5 /**< L data MSB during FRM LRC */
+#define SOF_DAI_FMT_PDM		6 /**< Pulse density modulation */
+
+#define SOF_DAI_FMT_CONT	(1 << 4) /**< continuous clock */
+#define SOF_DAI_FMT_GATED	(0 << 4) /**< clock is gated */
+
+#define SOF_DAI_FMT_NB_NF	(0 << 8) /**< normal bit clock + frame */
+#define SOF_DAI_FMT_NB_IF	(2 << 8) /**< normal BCLK + inv FRM */
+#define SOF_DAI_FMT_IB_NF	(3 << 8) /**< invert BCLK + nor FRM */
+#define SOF_DAI_FMT_IB_IF	(4 << 8) /**< invert BCLK + FRM */
+
+#define SOF_DAI_FMT_CBP_CFP	(0 << 12) /**< codec bclk provider & frame provider */
+#define SOF_DAI_FMT_CBC_CFP	(2 << 12) /**< codec bclk consumer & frame provider */
+#define SOF_DAI_FMT_CBP_CFC	(3 << 12) /**< codec bclk provider & frame consumer */
+#define SOF_DAI_FMT_CBC_CFC	(4 << 12) /**< codec bclk consumer & frame consumer */
+
+/* keep old definitions for backwards compatibility */
+#define SOF_DAI_FMT_CBM_CFM	SOF_DAI_FMT_CBP_CFP
+#define SOF_DAI_FMT_CBS_CFM	SOF_DAI_FMT_CBC_CFP
+#define SOF_DAI_FMT_CBM_CFS	SOF_DAI_FMT_CBP_CFC
+#define SOF_DAI_FMT_CBS_CFS	SOF_DAI_FMT_CBC_CFC
+
+#define SOF_DAI_FMT_FORMAT_MASK		0x000f
+#define SOF_DAI_FMT_CLOCK_MASK		0x00f0
+#define SOF_DAI_FMT_INV_MASK		0x0f00
+#define SOF_DAI_FMT_CLOCK_PROVIDER_MASK	0xf000
+
+/*
+ * DAI_CONFIG flags. The 4 LSB bits are used for the commands, HW_PARAMS, HW_FREE and PAUSE
+ * representing when the IPC is sent. The 4 MSB bits are used to add quirks along with the above
+ * commands.
+ */
+#define SOF_DAI_CONFIG_FLAGS_CMD_MASK	0xF
+#define SOF_DAI_CONFIG_FLAGS_NONE	0 /**< DAI_CONFIG sent without stage information */
+#define SOF_DAI_CONFIG_FLAGS_HW_PARAMS	BIT(0) /**< DAI_CONFIG sent during hw_params stage */
+#define SOF_DAI_CONFIG_FLAGS_HW_FREE	BIT(1) /**< DAI_CONFIG sent during hw_free stage */
+/**< DAI_CONFIG sent during pause trigger. Only available ABI 3.20 onwards */
+#define SOF_DAI_CONFIG_FLAGS_PAUSE	BIT(2)
+#define SOF_DAI_CONFIG_FLAGS_QUIRK_SHIFT 4
+#define SOF_DAI_CONFIG_FLAGS_QUIRK_MASK  (0xF << SOF_DAI_CONFIG_FLAGS_QUIRK_SHIFT)
+/*
+ * This should be used along with the SOF_DAI_CONFIG_FLAGS_HW_PARAMS to indicate that pipeline
+ * stop/pause and DAI DMA stop/pause should happen in two steps. This change is only available
+ * ABI 3.20 onwards.
+ */
+#define SOF_DAI_CONFIG_FLAGS_2_STEP_STOP BIT(0)
+
+/** \brief Types of DAI */
+enum sof_ipc_dai_type {
+	SOF_DAI_INTEL_NONE = 0,		/**< None */
+	SOF_DAI_INTEL_SSP,		/**< Intel SSP */
+	SOF_DAI_INTEL_DMIC,		/**< Intel DMIC */
+	SOF_DAI_INTEL_HDA,		/**< Intel HD/A */
+	SOF_DAI_INTEL_ALH,		/**< Intel ALH  */
+	SOF_DAI_IMX_SAI,		/**< i.MX SAI */
+	SOF_DAI_IMX_ESAI,		/**< i.MX ESAI */
+	SOF_DAI_AMD_BT,			/**< AMD ACP BT*/
+	SOF_DAI_AMD_SP,			/**< AMD ACP SP */
+	SOF_DAI_AMD_DMIC,		/**< AMD ACP DMIC */
+	SOF_DAI_MEDIATEK_AFE,		/**< Mediatek AFE */
+	SOF_DAI_AMD_HS,			/**< Amd HS */
+	SOF_DAI_AMD_SP_VIRTUAL,		/**< AMD ACP SP VIRTUAL */
+	SOF_DAI_AMD_HS_VIRTUAL,		/**< AMD ACP HS VIRTUAL */
+	SOF_DAI_IMX_MICFIL,		/** < i.MX MICFIL PDM */
+	SOF_DAI_AMD_SDW,		/**< AMD ACP SDW */
+	SOF_DAI_INTEL_UAOL,		/**< Intel UAOL */
+	SOF_DAI_AMD_I2S,		/**< AMD ACP I2S */
+};
+
+/* general purpose DAI configuration */
+struct sof_ipc_dai_config {
+	struct sof_ipc_cmd_hdr hdr;
+	uint32_t type;		/**< DAI type - enum sof_ipc_dai_type */
+	uint32_t dai_index;	/**< index of this type dai */
+
+	/* physical protocol and clocking */
+	uint16_t format;	/**< SOF_DAI_FMT_ */
+	uint8_t group_id;	/**< group ID, 0 means no group (ABI 3.17) */
+	uint8_t flags;		/**< SOF_DAI_CONFIG_FLAGS_ (ABI 3.19) */
+
+	/* reserved for future use */
+	uint32_t reserved[8];
+
+	/* HW specific data */
+	union {
+		struct sof_ipc_dai_ssp_params ssp;
+		struct sof_ipc_dai_dmic_params dmic;
+		struct sof_ipc_dai_hda_params hda;
+		struct sof_ipc_dai_alh_params alh;
+		struct sof_ipc_dai_esai_params esai;
+		struct sof_ipc_dai_sai_params sai;
+		struct sof_ipc_dai_acp_params acpbt;
+		struct sof_ipc_dai_acp_params acpsp;
+		struct sof_ipc_dai_acpdmic_params acpdmic;
+		struct sof_ipc_dai_acp_params acphs;
+		struct sof_ipc_dai_mtk_afe_params afe;
+		struct sof_ipc_dai_micfil_params micfil;
+		struct sof_ipc_dai_acp_sdw_params acp_sdw;
+		struct sof_ipc_dai_acp_params acp_i2s;
+	};
+} __packed;
+
+struct sof_dai_private_data {
+	struct sof_ipc_comp_dai *comp_dai;
+	struct sof_ipc_dai_config *dai_config;
+};
+
+#endif