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/bluetooth/btmrvl_debugfs.c | 193 +++++++++++++++++++++++++++++++++++++ 1 file changed, 193 insertions(+) create mode 100644 drivers/bluetooth/btmrvl_debugfs.c (limited to 'drivers/bluetooth/btmrvl_debugfs.c') diff --git a/drivers/bluetooth/btmrvl_debugfs.c b/drivers/bluetooth/btmrvl_debugfs.c new file mode 100644 index 000000000..9b3e768c0 --- /dev/null +++ b/drivers/bluetooth/btmrvl_debugfs.c @@ -0,0 +1,193 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Marvell Bluetooth driver: debugfs related functions + * + * Copyright (C) 2009, Marvell International Ltd. + **/ + +#include +#include + +#include +#include + +#include "btmrvl_drv.h" + +struct btmrvl_debugfs_data { + struct dentry *config_dir; + struct dentry *status_dir; +}; + +static ssize_t btmrvl_hscfgcmd_write(struct file *file, + const char __user *ubuf, size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + long result, ret; + + ret = kstrtol_from_user(ubuf, count, 10, &result); + if (ret) + return ret; + + priv->btmrvl_dev.hscfgcmd = result; + + if (priv->btmrvl_dev.hscfgcmd) { + btmrvl_prepare_command(priv); + wake_up_interruptible(&priv->main_thread.wait_q); + } + + return count; +} + +static ssize_t btmrvl_hscfgcmd_read(struct file *file, char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + char buf[16]; + int ret; + + ret = snprintf(buf, sizeof(buf) - 1, "%d\n", + priv->btmrvl_dev.hscfgcmd); + + return simple_read_from_buffer(userbuf, count, ppos, buf, ret); +} + +static const struct file_operations btmrvl_hscfgcmd_fops = { + .read = btmrvl_hscfgcmd_read, + .write = btmrvl_hscfgcmd_write, + .open = simple_open, + .llseek = default_llseek, +}; + +static ssize_t btmrvl_pscmd_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + long result, ret; + + ret = kstrtol_from_user(ubuf, count, 10, &result); + if (ret) + return ret; + + priv->btmrvl_dev.pscmd = result; + + if (priv->btmrvl_dev.pscmd) { + btmrvl_prepare_command(priv); + wake_up_interruptible(&priv->main_thread.wait_q); + } + + return count; + +} + +static ssize_t btmrvl_pscmd_read(struct file *file, char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + char buf[16]; + int ret; + + ret = snprintf(buf, sizeof(buf) - 1, "%d\n", priv->btmrvl_dev.pscmd); + + return simple_read_from_buffer(userbuf, count, ppos, buf, ret); +} + +static const struct file_operations btmrvl_pscmd_fops = { + .read = btmrvl_pscmd_read, + .write = btmrvl_pscmd_write, + .open = simple_open, + .llseek = default_llseek, +}; + +static ssize_t btmrvl_hscmd_write(struct file *file, const char __user *ubuf, + size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + long result, ret; + + ret = kstrtol_from_user(ubuf, count, 10, &result); + if (ret) + return ret; + + priv->btmrvl_dev.hscmd = result; + if (priv->btmrvl_dev.hscmd) { + btmrvl_prepare_command(priv); + wake_up_interruptible(&priv->main_thread.wait_q); + } + + return count; +} + +static ssize_t btmrvl_hscmd_read(struct file *file, char __user *userbuf, + size_t count, loff_t *ppos) +{ + struct btmrvl_private *priv = file->private_data; + char buf[16]; + int ret; + + ret = snprintf(buf, sizeof(buf) - 1, "%d\n", priv->btmrvl_dev.hscmd); + + return simple_read_from_buffer(userbuf, count, ppos, buf, ret); +} + +static const struct file_operations btmrvl_hscmd_fops = { + .read = btmrvl_hscmd_read, + .write = btmrvl_hscmd_write, + .open = simple_open, + .llseek = default_llseek, +}; + +void btmrvl_debugfs_init(struct hci_dev *hdev) +{ + struct btmrvl_private *priv = hci_get_drvdata(hdev); + struct btmrvl_debugfs_data *dbg; + + if (!hdev->debugfs) + return; + + dbg = kzalloc_obj(*dbg); + priv->debugfs_data = dbg; + + if (!dbg) { + BT_ERR("Can not allocate memory for btmrvl_debugfs_data."); + return; + } + + dbg->config_dir = debugfs_create_dir("config", hdev->debugfs); + + debugfs_create_u8("psmode", 0644, dbg->config_dir, + &priv->btmrvl_dev.psmode); + debugfs_create_file("pscmd", 0644, dbg->config_dir, + priv, &btmrvl_pscmd_fops); + debugfs_create_x16("gpiogap", 0644, dbg->config_dir, + &priv->btmrvl_dev.gpio_gap); + debugfs_create_u8("hsmode", 0644, dbg->config_dir, + &priv->btmrvl_dev.hsmode); + debugfs_create_file("hscmd", 0644, dbg->config_dir, + priv, &btmrvl_hscmd_fops); + debugfs_create_file("hscfgcmd", 0644, dbg->config_dir, + priv, &btmrvl_hscfgcmd_fops); + + dbg->status_dir = debugfs_create_dir("status", hdev->debugfs); + debugfs_create_u8("curpsmode", 0444, dbg->status_dir, + &priv->adapter->psmode); + debugfs_create_u8("psstate", 0444, dbg->status_dir, + &priv->adapter->ps_state); + debugfs_create_u8("hsstate", 0444, dbg->status_dir, + &priv->adapter->hs_state); + debugfs_create_u8("txdnldready", 0444, dbg->status_dir, + &priv->btmrvl_dev.tx_dnld_rdy); +} + +void btmrvl_debugfs_remove(struct hci_dev *hdev) +{ + struct btmrvl_private *priv = hci_get_drvdata(hdev); + struct btmrvl_debugfs_data *dbg = priv->debugfs_data; + + if (!dbg) + return; + + debugfs_remove_recursive(dbg->config_dir); + debugfs_remove_recursive(dbg->status_dir); + + kfree(dbg); +} -- cgit v1.3.1