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
