From 1b948d6caec4f28e3524244ca0f77c6ae8ddceef Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Thu, 3 Apr 2014 13:55:01 +0200 Subject: s390/mm,tlb: optimize TLB flushing for zEC12 The zEC12 machines introduced the local-clearing control for the IDTE and IPTE instruction. If the control is set only the TLB of the local CPU is cleared of entries, either all entries of a single address space for IDTE, or the entry for a single page-table entry for IPTE. Without the local-clearing control the TLB flush is broadcasted to all CPUs in the configuration, which is expensive. The reset of the bit mask of the CPUs that need flushing after a non-local IDTE is tricky. As TLB entries for an address space remain in the TLB even if the address space is detached a new bit field is required to keep track of attached CPUs vs. CPUs in the need of a flush. After a non-local flush with IDTE the bit-field of attached CPUs is copied to the bit-field of CPUs in need of a flush. The ordering of operations on cpu_attach_mask, attach_count and mm_cpumask(mm) is such that an underindication in mm_cpumask(mm) is prevented but an overindication in mm_cpumask(mm) is possible. Signed-off-by: Martin Schwidefsky --- arch/s390/include/asm/mmu.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/s390/include/asm/mmu.h') diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h index ff132ac64ddd..f77695a82f64 100644 --- a/arch/s390/include/asm/mmu.h +++ b/arch/s390/include/asm/mmu.h @@ -1,9 +1,11 @@ #ifndef __MMU_H #define __MMU_H +#include #include typedef struct { + cpumask_t cpu_attach_mask; atomic_t attach_count; unsigned int flush_mm; spinlock_t list_lock; -- cgit v1.2.2