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, 49 insertions, 0 deletions

diff --git a/drivers/char/tpm/Makefile b/drivers/char/tpm/Makefile
new file mode 100644
index 000000000..5b5cdc0d3
--- /dev/null
+++ b/drivers/char/tpm/Makefile
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Makefile for the kernel tpm device drivers.
+#
+obj-$(CONFIG_TCG_TPM) += tpm.o
+tpm-y := tpm-chip.o
+tpm-y += tpm-dev-common.o
+tpm-y += tpm-dev.o
+tpm-y += tpm-interface.o
+tpm-y += tpm1-cmd.o
+tpm-y += tpm2-cmd.o
+tpm-y += tpmrm-dev.o
+tpm-y += tpm2-space.o
+tpm-y += tpm-sysfs.o
+tpm-y += eventlog/common.o
+tpm-y += eventlog/tpm1.o
+tpm-y += eventlog/tpm2.o
+tpm-y += tpm-buf.o
+tpm-y += tpm2-sessions.o
+
+tpm-$(CONFIG_ACPI) += tpm_ppi.o eventlog/acpi.o
+tpm-$(CONFIG_EFI) += eventlog/efi.o
+tpm-$(CONFIG_OF) += eventlog/of.o
+obj-$(CONFIG_TCG_TIS_CORE) += tpm_tis_core.o
+obj-$(CONFIG_TCG_TIS) += tpm_tis.o
+obj-$(CONFIG_TCG_TIS_SYNQUACER) += tpm_tis_synquacer.o
+
+obj-$(CONFIG_TCG_TIS_SPI) += tpm_tis_spi.o
+tpm_tis_spi-y := tpm_tis_spi_main.o
+tpm_tis_spi-$(CONFIG_TCG_TIS_SPI_CR50) += tpm_tis_spi_cr50.o
+
+obj-$(CONFIG_TCG_TIS_I2C_CR50) += tpm_tis_i2c_cr50.o
+
+obj-$(CONFIG_TCG_TIS_I2C) += tpm_tis_i2c.o
+obj-$(CONFIG_TCG_TIS_I2C_ATMEL) += tpm_i2c_atmel.o
+obj-$(CONFIG_TCG_TIS_I2C_INFINEON) += tpm_i2c_infineon.o
+obj-$(CONFIG_TCG_TIS_I2C_NUVOTON) += tpm_i2c_nuvoton.o
+obj-$(CONFIG_TCG_NSC) += tpm_nsc.o
+obj-$(CONFIG_TCG_ATMEL) += tpm_atmel.o
+obj-$(CONFIG_TCG_INFINEON) += tpm_infineon.o
+obj-$(CONFIG_TCG_IBMVTPM) += tpm_ibmvtpm.o
+obj-$(CONFIG_TCG_TIS_ST33ZP24) += st33zp24/
+obj-$(CONFIG_TCG_XEN) += xen-tpmfront.o
+obj-$(CONFIG_TCG_CRB) += tpm_crb.o
+obj-$(CONFIG_TCG_ARM_CRB_FFA) += tpm_crb_ffa.o
+obj-$(CONFIG_TCG_VTPM_PROXY) += tpm_vtpm_proxy.o
+obj-$(CONFIG_TCG_FTPM_TEE) += tpm_ftpm_tee.o
+obj-$(CONFIG_TCG_SVSM) += tpm_svsm.o
+obj-$(CONFIG_TCG_LOONGSON) += tpm_loongson.o