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

46 files changed, 190 insertions, 0 deletions

diff --git a/tools/bootconfig/samples/bad-array-after-comment.bconf b/tools/bootconfig/samples/bad-array-after-comment.bconf
new file mode 100644
index 000000000..fdb6d4e04
--- /dev/null
+++ b/tools/bootconfig/samples/bad-array-after-comment.bconf
@@ -0,0 +1,4 @@
+# the first array value must be on the same line as the key
+key = # comment
+ value1,
+ value2
diff --git a/tools/bootconfig/samples/bad-array-in-next-line.bconf b/tools/bootconfig/samples/bad-array-in-next-line.bconf
new file mode 100644
index 000000000..95a99a3bd
--- /dev/null
+++ b/tools/bootconfig/samples/bad-array-in-next-line.bconf
@@ -0,0 +1,4 @@
+# the first array value must be on the same line as the key
+key =
+  value1,
+  value2
diff --git a/tools/bootconfig/samples/bad-array-space-comment.bconf b/tools/bootconfig/samples/bad-array-space-comment.bconf
new file mode 100644
index 000000000..fda19e47d
--- /dev/null
+++ b/tools/bootconfig/samples/bad-array-space-comment.bconf
@@ -0,0 +1,5 @@
+key =	# comment
+	"value1",	  # comment1
+	"value2" 	  # comment2
+,
+	"value3"
diff --git a/tools/bootconfig/samples/bad-array.bconf b/tools/bootconfig/samples/bad-array.bconf
new file mode 100644
index 000000000..0174af019
--- /dev/null
+++ b/tools/bootconfig/samples/bad-array.bconf
@@ -0,0 +1,2 @@
+# Array must be comma separated.
+key = "value1" "value2"
diff --git a/tools/bootconfig/samples/bad-dotword.bconf b/tools/bootconfig/samples/bad-dotword.bconf
new file mode 100644
index 000000000..ba5557b2b
--- /dev/null
+++ b/tools/bootconfig/samples/bad-dotword.bconf
@@ -0,0 +1,4 @@
+# do not start keyword with .
+key {
+  .word = 1
+}
diff --git a/tools/bootconfig/samples/bad-empty.bconf b/tools/bootconfig/samples/bad-empty.bconf
new file mode 100644
index 000000000..2ba3f6cc6
--- /dev/null
+++ b/tools/bootconfig/samples/bad-empty.bconf
@@ -0,0 +1 @@
+# Wrong boot config: comment only
diff --git a/tools/bootconfig/samples/bad-keyerror.bconf b/tools/bootconfig/samples/bad-keyerror.bconf
new file mode 100644
index 000000000..b6e247a09
--- /dev/null
+++ b/tools/bootconfig/samples/bad-keyerror.bconf
@@ -0,0 +1,2 @@
+# key word can not contain ","
+key,word
diff --git a/tools/bootconfig/samples/bad-longkey.bconf b/tools/bootconfig/samples/bad-longkey.bconf
new file mode 100644
index 000000000..eb97369f9
--- /dev/null
+++ b/tools/bootconfig/samples/bad-longkey.bconf
@@ -0,0 +1 @@
+key_word_is_too_long01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345
diff --git a/tools/bootconfig/samples/bad-manywords.bconf b/tools/bootconfig/samples/bad-manywords.bconf
new file mode 100644
index 000000000..8db81967c
--- /dev/null
+++ b/tools/bootconfig/samples/bad-manywords.bconf
@@ -0,0 +1 @@
+key1.is2.too3.long4.5.6.7.8.9.10.11.12.13.14.15.16.17
diff --git a/tools/bootconfig/samples/bad-no-keyword.bconf b/tools/bootconfig/samples/bad-no-keyword.bconf
new file mode 100644
index 000000000..eff268085
--- /dev/null
+++ b/tools/bootconfig/samples/bad-no-keyword.bconf
@@ -0,0 +1,2 @@
+# No keyword
+{}
diff --git a/tools/bootconfig/samples/bad-non-closed-brace.bconf b/tools/bootconfig/samples/bad-non-closed-brace.bconf
new file mode 100644
index 000000000..6ed9f3363
--- /dev/null
+++ b/tools/bootconfig/samples/bad-non-closed-brace.bconf
@@ -0,0 +1,4 @@
+foo {
+ bar {
+   buz
+ }
diff --git a/tools/bootconfig/samples/bad-nonprintable.bconf b/tools/bootconfig/samples/bad-nonprintable.bconf
new file mode 100644
index 000000000..3bb1a2864
--- /dev/null
+++ b/tools/bootconfig/samples/bad-nonprintable.bconf
@@ -0,0 +1,2 @@
+# Non printable
+key = ""
diff --git a/tools/bootconfig/samples/bad-over-max-brace.bconf b/tools/bootconfig/samples/bad-over-max-brace.bconf
new file mode 100644
index 000000000..74b5dc9e2
--- /dev/null
+++ b/tools/bootconfig/samples/bad-over-max-brace.bconf
@@ -0,0 +1,19 @@
+key1 {
+key2 {
+key3 {
+key4 {
+key5 {
+key6 {
+key7 {
+key8 {
+key9 {
+key10 {
+key11 {
+key12 {
+key13 {
+key14 {
+key15 {
+key16 {
+key17 {
+}}}}}}}}}}}}}}}}}
+
diff --git a/tools/bootconfig/samples/bad-samekey.bconf b/tools/bootconfig/samples/bad-samekey.bconf
new file mode 100644
index 000000000..e8d983a45
--- /dev/null
+++ b/tools/bootconfig/samples/bad-samekey.bconf
@@ -0,0 +1,6 @@
+# Same key value is not allowed
+key {
+	foo = value
+	bar = value2
+}
+key.foo = value
diff --git a/tools/bootconfig/samples/bad-spaceword.bconf b/tools/bootconfig/samples/bad-spaceword.bconf
new file mode 100644
index 000000000..90c703d32
--- /dev/null
+++ b/tools/bootconfig/samples/bad-spaceword.bconf
@@ -0,0 +1,2 @@
+# No space between words
+key . word
diff --git a/tools/bootconfig/samples/bad-tree.bconf b/tools/bootconfig/samples/bad-tree.bconf
new file mode 100644
index 000000000..5a6038edc
--- /dev/null
+++ b/tools/bootconfig/samples/bad-tree.bconf
@@ -0,0 +1,5 @@
+# brace is not closing
+tree {
+  node {
+    value = 1
+}
diff --git a/tools/bootconfig/samples/bad-value.bconf b/tools/bootconfig/samples/bad-value.bconf
new file mode 100644
index 000000000..a1217fed8
--- /dev/null
+++ b/tools/bootconfig/samples/bad-value.bconf
@@ -0,0 +1,3 @@
+# Quotes error
+value = "data
+
diff --git a/tools/bootconfig/samples/escaped.bconf b/tools/bootconfig/samples/escaped.bconf
new file mode 100644
index 000000000..9f72043b3
--- /dev/null
+++ b/tools/bootconfig/samples/escaped.bconf
@@ -0,0 +1,3 @@
+key1 = "A\B\C"
+key2 = '\'\''
+key3 = "\\"
diff --git a/tools/bootconfig/samples/exp-good-array-space-comment.bconf b/tools/bootconfig/samples/exp-good-array-space-comment.bconf
new file mode 100644
index 000000000..8d3278fa6
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-array-space-comment.bconf
@@ -0,0 +1 @@
+key = "value1", "value2", "value3";
diff --git a/tools/bootconfig/samples/exp-good-comment-after-value.bconf b/tools/bootconfig/samples/exp-good-comment-after-value.bconf
new file mode 100644
index 000000000..a8e8450db
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-comment-after-value.bconf
@@ -0,0 +1 @@
+key = "value";
diff --git a/tools/bootconfig/samples/exp-good-mixed-append.bconf b/tools/bootconfig/samples/exp-good-mixed-append.bconf
new file mode 100644
index 000000000..c2b407901
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-mixed-append.bconf
@@ -0,0 +1,2 @@
+key = "foo", "bar";
+keyx.subkey = "value";
diff --git a/tools/bootconfig/samples/exp-good-mixed-kv1.bconf b/tools/bootconfig/samples/exp-good-mixed-kv1.bconf
new file mode 100644
index 000000000..8346287d9
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-mixed-kv1.bconf
@@ -0,0 +1,2 @@
+key = "value";
+key.subkey = "another-value";
diff --git a/tools/bootconfig/samples/exp-good-mixed-kv2.bconf b/tools/bootconfig/samples/exp-good-mixed-kv2.bconf
new file mode 100644
index 000000000..40c6232c7
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-mixed-kv2.bconf
@@ -0,0 +1,2 @@
+key = "another-value";
+key.subkey = "value";
diff --git a/tools/bootconfig/samples/exp-good-mixed-kv3.bconf b/tools/bootconfig/samples/exp-good-mixed-kv3.bconf
new file mode 100644
index 000000000..8368a7bef
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-mixed-kv3.bconf
@@ -0,0 +1,5 @@
+key = "value";
+key {
+	subkey1;
+	subkey2 = "foo";
+}
diff --git a/tools/bootconfig/samples/exp-good-mixed-override.bconf b/tools/bootconfig/samples/exp-good-mixed-override.bconf
new file mode 100644
index 000000000..58757712c
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-mixed-override.bconf
@@ -0,0 +1,2 @@
+key = "value2";
+key.foo = "bar";
diff --git a/tools/bootconfig/samples/exp-good-nested-brace.bconf b/tools/bootconfig/samples/exp-good-nested-brace.bconf
new file mode 100644
index 000000000..19e0f51b4
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-nested-brace.bconf
@@ -0,0 +1 @@
+key1.key2.key3.key4.key5.key6.key7.key8.key9.key10.key11.key12.key13.key14.key15.key16;
diff --git a/tools/bootconfig/samples/exp-good-override.bconf b/tools/bootconfig/samples/exp-good-override.bconf
new file mode 100644
index 000000000..00bbd30e9
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-override.bconf
@@ -0,0 +1,4 @@
+key {
+	word = "2", "3";
+	new.word = "new";
+}
diff --git a/tools/bootconfig/samples/exp-good-printables.bconf b/tools/bootconfig/samples/exp-good-printables.bconf
new file mode 100644
index 000000000..5981d304e
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-printables.bconf
@@ -0,0 +1,2 @@
+key = "	
+ !#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~";
diff --git a/tools/bootconfig/samples/exp-good-simple.bconf b/tools/bootconfig/samples/exp-good-simple.bconf
new file mode 100644
index 000000000..d17f39421
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-simple.bconf
@@ -0,0 +1,8 @@
+key {
+	word1 = "1";
+	word2 = "2";
+	word3 = "3";
+	word4 = "4";
+	word5 = "5";
+	word6 = "6";
+}
diff --git a/tools/bootconfig/samples/exp-good-single.bconf b/tools/bootconfig/samples/exp-good-single.bconf
new file mode 100644
index 000000000..01196910d
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-single.bconf
@@ -0,0 +1,3 @@
+key = "1";
+key2 = "2";
+key3 = "alpha", "beta";
diff --git a/tools/bootconfig/samples/exp-good-space-after-value.bconf b/tools/bootconfig/samples/exp-good-space-after-value.bconf
new file mode 100644
index 000000000..a8e8450db
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-space-after-value.bconf
@@ -0,0 +1 @@
+key = "value";
diff --git a/tools/bootconfig/samples/exp-good-tree.bconf b/tools/bootconfig/samples/exp-good-tree.bconf
new file mode 100644
index 000000000..b711d38d8
--- /dev/null
+++ b/tools/bootconfig/samples/exp-good-tree.bconf
@@ -0,0 +1,8 @@
+key {
+	word.tree.value = "0";
+	word2.tree.value = "1", "2";
+}
+other.tree {
+	value = "2";
+	value2 = "3";
+}
diff --git a/tools/bootconfig/samples/good-array-space-comment.bconf b/tools/bootconfig/samples/good-array-space-comment.bconf
new file mode 100644
index 000000000..416fa2ed4
--- /dev/null
+++ b/tools/bootconfig/samples/good-array-space-comment.bconf
@@ -0,0 +1,3 @@
+key = "value1",	  # comment1
+	"value2"	 , # comment2
+	"value3"
diff --git a/tools/bootconfig/samples/good-comment-after-value.bconf b/tools/bootconfig/samples/good-comment-after-value.bconf
new file mode 100644
index 000000000..0d92a853d
--- /dev/null
+++ b/tools/bootconfig/samples/good-comment-after-value.bconf
@@ -0,0 +1 @@
+key = "value"  # comment
diff --git a/tools/bootconfig/samples/good-mixed-append.bconf b/tools/bootconfig/samples/good-mixed-append.bconf
new file mode 100644
index 000000000..b99a089a0
--- /dev/null
+++ b/tools/bootconfig/samples/good-mixed-append.bconf
@@ -0,0 +1,4 @@
+key = foo
+keyx.subkey = value
+key += bar
+
diff --git a/tools/bootconfig/samples/good-mixed-kv1.bconf b/tools/bootconfig/samples/good-mixed-kv1.bconf
new file mode 100644
index 000000000..1761547dd
--- /dev/null
+++ b/tools/bootconfig/samples/good-mixed-kv1.bconf
@@ -0,0 +1,3 @@
+# value -> subkey pattern
+key = value
+key.subkey = another-value
diff --git a/tools/bootconfig/samples/good-mixed-kv2.bconf b/tools/bootconfig/samples/good-mixed-kv2.bconf
new file mode 100644
index 000000000..6b32e0c38
--- /dev/null
+++ b/tools/bootconfig/samples/good-mixed-kv2.bconf
@@ -0,0 +1,3 @@
+# subkey -> value pattern
+key.subkey = value
+key = another-value
diff --git a/tools/bootconfig/samples/good-mixed-kv3.bconf b/tools/bootconfig/samples/good-mixed-kv3.bconf
new file mode 100644
index 000000000..2ce2b0222
--- /dev/null
+++ b/tools/bootconfig/samples/good-mixed-kv3.bconf
@@ -0,0 +1,6 @@
+# mixed key and subkeys with braces
+key = value
+key {
+	subkey1
+	subkey2 = foo
+}
diff --git a/tools/bootconfig/samples/good-mixed-override.bconf b/tools/bootconfig/samples/good-mixed-override.bconf
new file mode 100644
index 000000000..18195b287
--- /dev/null
+++ b/tools/bootconfig/samples/good-mixed-override.bconf
@@ -0,0 +1,4 @@
+key.foo = bar
+key = value
+# mixed key value can be overridden
+key := value2
diff --git a/tools/bootconfig/samples/good-nested-brace.bconf b/tools/bootconfig/samples/good-nested-brace.bconf
new file mode 100644
index 000000000..980d094f2
--- /dev/null
+++ b/tools/bootconfig/samples/good-nested-brace.bconf
@@ -0,0 +1,18 @@
+key1 {
+key2 {
+key3 {
+key4 {
+key5 {
+key6 {
+key7 {
+key8 {
+key9 {
+key10 {
+key11 {
+key12 {
+key13 {
+key14 {
+key15 {
+key16 {
+}}}}}}}}}}}}}}}}
+
diff --git a/tools/bootconfig/samples/good-override.bconf b/tools/bootconfig/samples/good-override.bconf
new file mode 100644
index 000000000..7d31d5f8f
--- /dev/null
+++ b/tools/bootconfig/samples/good-override.bconf
@@ -0,0 +1,6 @@
+# Override the value
+key.word = 1,2,4
+key.word := 2,3
+
+# No pre-defined key
+key.new.word := "new"
diff --git a/tools/bootconfig/samples/good-printables.bconf b/tools/bootconfig/samples/good-printables.bconf
new file mode 100644
index 000000000..ebb985a66
--- /dev/null
+++ b/tools/bootconfig/samples/good-printables.bconf
@@ -0,0 +1,2 @@
+key = "	
+ !#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~"
diff --git a/tools/bootconfig/samples/good-simple.bconf b/tools/bootconfig/samples/good-simple.bconf
new file mode 100644
index 000000000..37dd6d21c
--- /dev/null
+++ b/tools/bootconfig/samples/good-simple.bconf
@@ -0,0 +1,11 @@
+# A good simple bootconfig
+
+key.word1 = 1
+key.word2=2
+key.word3 = 3;
+
+key {
+word4 = 4 }
+
+key { word5 = 5; word6 = 6 }
+
diff --git a/tools/bootconfig/samples/good-single.bconf b/tools/bootconfig/samples/good-single.bconf
new file mode 100644
index 000000000..98e55ad8b
--- /dev/null
+++ b/tools/bootconfig/samples/good-single.bconf
@@ -0,0 +1,4 @@
+# single key style
+key = 1
+key2 = 2
+key3 = "alpha", "beta"
diff --git a/tools/bootconfig/samples/good-space-after-value.bconf b/tools/bootconfig/samples/good-space-after-value.bconf
new file mode 100644
index 000000000..56c15cbc5
--- /dev/null
+++ b/tools/bootconfig/samples/good-space-after-value.bconf
@@ -0,0 +1 @@
+key = "value"   
diff --git a/tools/bootconfig/samples/good-tree.bconf b/tools/bootconfig/samples/good-tree.bconf
new file mode 100644
index 000000000..f2ddefc8b
--- /dev/null
+++ b/tools/bootconfig/samples/good-tree.bconf
@@ -0,0 +1,12 @@
+key {
+  word {
+    tree {
+      value = "0"}
+  }
+  word2 {
+    tree {
+      value = 1,2 }
+  }
+}
+other.tree {
+  value = 2; value2 = 3;}