From: Nadav Amit <namit@vmware.com>
Date: Wed, 31 Jan 2018 21:19:12 +0000 (-0800)
Subject: x86/mm: Align TLB invalidation info
X-Git-Tag: v4.19~1349^2~58
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=515ab7c41306aad1f80a980e1936ef635c61570c;p=platform%2Fkernel%2Flinux-rpi.git

x86/mm: Align TLB invalidation info

The TLB invalidation info is allocated on the stack, which might cause
it to be unaligned. Since this information may be transferred to
different cores for TLB shootdown, this may cause an additional cache
line to become shared. While the overhead is likely to be small, the
fix is simple.

We do not use __cacheline_aligned() since it also defines the section,
which is inappropriate for stack variables.

Signed-off-by: Nadav Amit <namit@vmware.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20180131211912.52064-1-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 8dcc060..6550d37 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -613,7 +613,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
 {
 	int cpu;
 
-	struct flush_tlb_info info = {
+	struct flush_tlb_info info __aligned(SMP_CACHE_BYTES) = {
 		.mm = mm,
 	};