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/misc/eeprom/Kconfig | 48 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) create mode 100644 drivers/misc/eeprom/Kconfig (limited to 'drivers/misc/eeprom/Kconfig') diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig new file mode 100644 index 000000000..d6af02588 --- /dev/null +++ b/drivers/misc/eeprom/Kconfig @@ -0,0 +1,48 @@ +# SPDX-License-Identifier: GPL-2.0-only +menu "EEPROM support" + +config EEPROM_MAX6875 + tristate "Maxim MAX6874/5 power supply supervisor" + depends on I2C + help + If you say yes here you get read-only support for the user EEPROM of + the Maxim MAX6874/5 EEPROM-programmable, quad power-supply + sequencer/supervisor. + + All other features of this chip should be accessed via i2c-dev. + + This driver can also be built as a module. If so, the module + will be called max6875. + + +config EEPROM_93CX6 + tristate "EEPROM 93CX6 support" + help + This is a driver for the EEPROM chipsets 93c46 and 93c66. + The driver supports both read as well as write commands. + + If unsure, say N. + +config EEPROM_DIGSY_MTC_CFG + bool "DigsyMTC display configuration EEPROMs device" + depends on GPIO_MPC5200 && SPI_GPIO + help + This option enables access to display configuration EEPROMs + on digsy_mtc board. You have to additionally select Microwire + EEPROM 93XX46 driver. sysfs entries will be created for that + EEPROM allowing to read/write the configuration data or to + erase the whole EEPROM. + + If unsure, say N. + +config EEPROM_IDT_89HPESX + tristate "IDT 89HPESx PCIe-switches EEPROM / CSR support" + depends on I2C && SYSFS + help + Enable this driver to get read/write access to EEPROM / CSRs + over IDT PCIe-switch i2c-slave interface. + + This driver can also be built as a module. If so, the module + will be called idt_89hpesx. + +endmenu -- cgit v1.3.1