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/mm/hugetlbpage.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) (limited to 'arch/s390/mm/hugetlbpage.c') diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c index d261c62e40a6..0727a55d87d9 100644 --- a/arch/s390/mm/hugetlbpage.c +++ b/arch/s390/mm/hugetlbpage.c @@ -123,10 +123,7 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm, pmd_t *pmdp = (pmd_t *) ptep; pte_t pte = huge_ptep_get(ptep); - if (MACHINE_HAS_IDTE) - __pmd_idte(addr, pmdp); - else - __pmd_csp(pmdp); + pmdp_flush_direct(mm, addr, pmdp); pmd_val(*pmdp) = _SEGMENT_ENTRY_EMPTY; return pte; } -- cgit v1.2.3-59-g8ed1b