s390: mmu_gather rework

Adapt the stand-alone s390 mmu_gather implementation to the new
preemptible mmu_gather interface.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 37 insertions, 25 deletions

diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
index 9074a54c4d10..77eee5477a52 100644
--- a/arch/s390/include/asm/tlb.h
+++ b/arch/s390/include/asm/tlb.h
@@ -29,65 +29,77 @@
 #include <asm/smp.h>
 #include <asm/tlbflush.h>
 
-#ifndef CONFIG_SMP
-#define TLB_NR_PTRS     1
-#else
-#define TLB_NR_PTRS     508
-#endif
-
 struct mmu_gather {
         struct mm_struct *mm;
         unsigned int fullmm;
         unsigned int nr_ptes;
         unsigned int nr_pxds;
-        void *array[TLB_NR_PTRS];
+        unsigned int max;
+        void **array;
+        void *local[8];
 };
 
-DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
-
-static inline struct mmu_gather *tlb_gather_mmu(struct mm_struct *mm,
-                                                unsigned int full_mm_flush)
+static inline void __tlb_alloc_page(struct mmu_gather *tlb)
 {
-        struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
+        unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
 
+        if (addr) {
+                tlb->array = (void *) addr;
+                tlb->max = PAGE_SIZE / sizeof(void *);
+        }
+}
+
+static inline void tlb_gather_mmu(struct mmu_gather *tlb,
+                                  struct mm_struct *mm,
+                                  unsigned int full_mm_flush)
+{
         tlb->mm = mm;
+        tlb->max = ARRAY_SIZE(tlb->local);
+        tlb->array = tlb->local;
         tlb->fullmm = full_mm_flush;
-        tlb->nr_ptes = 0;
-        tlb->nr_pxds = TLB_NR_PTRS;
         if (tlb->fullmm)
                 __tlb_flush_mm(mm);
-        return tlb;
+        else
+                __tlb_alloc_page(tlb);
+        tlb->nr_ptes = 0;
+        tlb->nr_pxds = tlb->max;
 }
 
-static inline void tlb_flush_mmu(struct mmu_gather *tlb,
-                                 unsigned long start, unsigned long end)
+static inline void tlb_flush_mmu(struct mmu_gather *tlb)
 {
-        if (!tlb->fullmm && (tlb->nr_ptes > 0 || tlb->nr_pxds < TLB_NR_PTRS))
+        if (!tlb->fullmm && (tlb->nr_ptes > 0 || tlb->nr_pxds < tlb->max))
                 __tlb_flush_mm(tlb->mm);
         while (tlb->nr_ptes > 0)
                 page_table_free_rcu(tlb->mm, tlb->array[--tlb->nr_ptes]);
-        while (tlb->nr_pxds < TLB_NR_PTRS)
+        while (tlb->nr_pxds < tlb->max)
                 crst_table_free_rcu(tlb->mm, tlb->array[tlb->nr_pxds++]);
 }
 
 static inline void tlb_finish_mmu(struct mmu_gather *tlb,
                                   unsigned long start, unsigned long end)
 {
-        tlb_flush_mmu(tlb, start, end);
+        tlb_flush_mmu(tlb);
 
         rcu_table_freelist_finish();
 
         /* keep the page table cache within bounds */
         check_pgt_cache();
 
-        put_cpu_var(mmu_gathers);
+        if (tlb->array != tlb->local)
+                free_pages((unsigned long) tlb->array, 0);
 }
 
 /*
  * Release the page cache reference for a pte removed by
- * tlb_ptep_clear_flush. In both flush modes the tlb fo a page cache page
+ * tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
  * has already been freed, so just do free_page_and_swap_cache.
  */
+static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+        free_page_and_swap_cache(page);
+        return 1; /* avoid calling tlb_flush_mmu */
+}
+
 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 {
         free_page_and_swap_cache(page);
@@ -103,7 +115,7 @@ static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
         if (!tlb->fullmm) {
                 tlb->array[tlb->nr_ptes++] = pte;
                 if (tlb->nr_ptes >= tlb->nr_pxds)
-                        tlb_flush_mmu(tlb, 0, 0);
+                        tlb_flush_mmu(tlb);
         } else
                 page_table_free(tlb->mm, (unsigned long *) pte);
 }
@@ -124,7 +136,7 @@ static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
         if (!tlb->fullmm) {
                 tlb->array[--tlb->nr_pxds] = pmd;
                 if (tlb->nr_ptes >= tlb->nr_pxds)
-                        tlb_flush_mmu(tlb, 0, 0);
+                        tlb_flush_mmu(tlb);
         } else
                 crst_table_free(tlb->mm, (unsigned long *) pmd);
 #endif
@@ -146,7 +158,7 @@ static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
         if (!tlb->fullmm) {
                 tlb->array[--tlb->nr_pxds] = pud;
                 if (tlb->nr_ptes >= tlb->nr_pxds)
-                        tlb_flush_mmu(tlb, 0, 0);
+                        tlb_flush_mmu(tlb);
         } else
                 crst_table_free(tlb->mm, (unsigned long *) pud);
 #endif