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, 45 insertions, 0 deletions

diff --git a/drivers/misc/cardreader/rts5260.h b/drivers/misc/cardreader/rts5260.h
new file mode 100644
index 000000000..53a1411c8
--- /dev/null
+++ b/drivers/misc/cardreader/rts5260.h
@@ -0,0 +1,45 @@
+#ifndef __RTS5260_H__
+#define __RTS5260_H__
+
+#define RTS5260_DVCC_CTRL		0xFF73
+#define RTS5260_DVCC_OCP_EN		(0x01 << 7)
+#define RTS5260_DVCC_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DVCC_POWERON		(0x01 << 3)
+#define RTS5260_DVCC_OCP_CL_EN		(0x01 << 2)
+
+#define RTS5260_DVIO_CTRL		0xFF75
+#define RTS5260_DVIO_OCP_EN		(0x01 << 7)
+#define RTS5260_DVIO_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DVIO_POWERON		(0x01 << 3)
+#define RTS5260_DVIO_OCP_CL_EN		(0x01 << 2)
+
+#define RTS5260_DV331812_CFG		0xFF71
+#define RTS5260_DV331812_OCP_EN		(0x01 << 7)
+#define RTS5260_DV331812_OCP_THD_MASK	(0x07 << 4)
+#define RTS5260_DV331812_POWERON	(0x01 << 3)
+#define RTS5260_DV331812_SEL		(0x01 << 2)
+#define RTS5260_DV331812_VDD1		(0x01 << 2)
+#define RTS5260_DV331812_VDD2		(0x00 << 2)
+
+#define RTS5260_DV331812_OCP_THD_120	(0x00 << 4)
+#define RTS5260_DV331812_OCP_THD_140	(0x01 << 4)
+#define RTS5260_DV331812_OCP_THD_160	(0x02 << 4)
+#define RTS5260_DV331812_OCP_THD_180	(0x03 << 4)
+#define RTS5260_DV331812_OCP_THD_210	(0x04 << 4)
+#define RTS5260_DV331812_OCP_THD_240	(0x05 << 4)
+#define RTS5260_DV331812_OCP_THD_270	(0x06 << 4)
+#define RTS5260_DV331812_OCP_THD_300	(0x07 << 4)
+
+#define RTS5260_DVIO_OCP_THD_250	(0x00 << 4)
+#define RTS5260_DVIO_OCP_THD_300	(0x01 << 4)
+#define RTS5260_DVIO_OCP_THD_350	(0x02 << 4)
+#define RTS5260_DVIO_OCP_THD_400	(0x03 << 4)
+#define RTS5260_DVIO_OCP_THD_450	(0x04 << 4)
+#define RTS5260_DVIO_OCP_THD_500	(0x05 << 4)
+#define RTS5260_DVIO_OCP_THD_550	(0x06 << 4)
+#define RTS5260_DVIO_OCP_THD_600	(0x07 << 4)
+
+#define RTS5260_DVCC_OCP_THD_550	(0x00 << 4)
+#define RTS5260_DVCC_OCP_THD_970	(0x05 << 4)
+
+#endif