From a5b702a9e5161eb9f11b322ae8b9460916cdda11 Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 26 Feb 2021 17:26:04 +0100
Subject: [PATCH 201/327] mm: slub: Don't resize the location tracking cache on
 PREEMPT_RT

The location tracking cache has a size of a page and is resized if its
current size is too small.
This allocation happens with disabled interrupts and can't happen on
PREEMPT_RT.
Should one page be too small, then we have to allocate more at the
beginning. The only downside is that less callers will be visible.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 mm/slub.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index cb414c1f9ef6..57c598dd7454 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4682,6 +4682,9 @@ static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
 	struct location *l;
 	int order;
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && flags == GFP_ATOMIC)
+		return 0;
+
 	order = get_order(sizeof(struct location) * max);
 
 	l = (void *)__get_free_pages(flags, order);
-- 
2.49.0

