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 <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
--
v2 -> v3: rewording the commit message (Andy)
v1 -> v2: use __aligned instead of all the mess (Andy)
---
arch/x86/mm/tlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 5bfe61a5e8e3..9690112e3a82 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -576,7 +576,7 @@ 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,
};
--
2.14.1
Commit-ID: 515ab7c41306aad1f80a980e1936ef635c61570c
Gitweb: https://git.kernel.org/tip/515ab7c41306aad1f80a980e1936ef635c61570c
Author: Nadav Amit <[email protected]>
AuthorDate: Wed, 31 Jan 2018 13:19:12 -0800
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 13 Feb 2018 15:05:49 +0100
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 <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/mm/tlb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
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,
};