From: Josh Don <joshdon@google.com>
Date: Tue, 4 Aug 2020 19:34:13 +0000 (-0700)
Subject: sched/fair: Ignore cache hotness for SMT migration
X-Git-Tag: v5.10-rc1~203^2~25
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ec73240b1627cddfd7cef018c7fa1c32e64a721e;p=thirdparty%2Fkernel%2Flinux.git

sched/fair: Ignore cache hotness for SMT migration

SMT siblings share caches, so cache hotness should be irrelevant for
cross-sibling migration.

Signed-off-by: Josh Don <joshdon@google.com>
Proposed-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200804193413.510651-1-joshdon@google.com
---

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 1a68a0536adda..abdb54e2339f4 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7402,6 +7402,10 @@ static int task_hot(struct task_struct *p, struct lb_env *env)
 	if (unlikely(task_has_idle_policy(p)))
 		return 0;
 
+	/* SMT siblings share cache */
+	if (env->sd->flags & SD_SHARE_CPUCAPACITY)
+		return 0;
+
 	/*
 	 * Buddy candidates are cache hot:
 	 */