1 files changed, 122 insertions, 2 deletions

diff --git a/mm/memory.c b/mm/memory.c
index 7bbe4d3df756..b73f677f0bb1 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -182,7 +182,7 @@ void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
 {
         __sync_task_rss_stat(task, mm);
 }
-#else
+#else /* SPLIT_RSS_COUNTING */
 
 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
@@ -191,8 +191,128 @@ static void check_sync_rss_stat(struct task_struct *task)
 {
 }
 
+#endif /* SPLIT_RSS_COUNTING */
+
+#ifdef HAVE_GENERIC_MMU_GATHER
+
+static int tlb_next_batch(struct mmu_gather *tlb)
+{
+        struct mmu_gather_batch *batch;
+
+        batch = tlb->active;
+        if (batch->next) {
+                tlb->active = batch->next;
+                return 1;
+        }
+
+        batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+        if (!batch)
+                return 0;
+
+        batch->next = NULL;
+        batch->nr   = 0;
+        batch->max  = MAX_GATHER_BATCH;
+
+        tlb->active->next = batch;
+        tlb->active = batch;
+
+        return 1;
+}
+
+/* tlb_gather_mmu
+ *      Called to initialize an (on-stack) mmu_gather structure for page-table
+ *      tear-down from @mm. The @fullmm argument is used when @mm is without
+ *      users and we're going to destroy the full address space (exit/execve).
+ */
+void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
+{
+        tlb->mm = mm;
+
+        tlb->fullmm     = fullmm;
+        tlb->need_flush = 0;
+        tlb->fast_mode  = (num_possible_cpus() == 1);
+        tlb->local.next = NULL;
+        tlb->local.nr   = 0;
+        tlb->local.max  = ARRAY_SIZE(tlb->__pages);
+        tlb->active     = &tlb->local;
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+        tlb->batch = NULL;
+#endif
+}
+
+void tlb_flush_mmu(struct mmu_gather *tlb)
+{
+        struct mmu_gather_batch *batch;
+
+        if (!tlb->need_flush)
+                return;
+        tlb->need_flush = 0;
+        tlb_flush(tlb);
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+        tlb_table_flush(tlb);
 #endif
 
+        if (tlb_fast_mode(tlb))
+                return;
+
+        for (batch = &tlb->local; batch; batch = batch->next) {
+                free_pages_and_swap_cache(batch->pages, batch->nr);
+                batch->nr = 0;
+        }
+        tlb->active = &tlb->local;
+}
+
+/* tlb_finish_mmu
+ *      Called at the end of the shootdown operation to free up any resources
+ *      that were required.
+ */
+void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+        struct mmu_gather_batch *batch, *next;
+
+        tlb_flush_mmu(tlb);
+
+        /* keep the page table cache within bounds */
+        check_pgt_cache();
+
+        for (batch = tlb->local.next; batch; batch = next) {
+                next = batch->next;
+                free_pages((unsigned long)batch, 0);
+        }
+        tlb->local.next = NULL;
+}
+
+/* __tlb_remove_page
+ *      Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
+ *      handling the additional races in SMP caused by other CPUs caching valid
+ *      mappings in their TLBs. Returns the number of free page slots left.
+ *      When out of page slots we must call tlb_flush_mmu().
+ */
+int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+        struct mmu_gather_batch *batch;
+
+        tlb->need_flush = 1;
+
+        if (tlb_fast_mode(tlb)) {
+                free_page_and_swap_cache(page);
+                return 1; /* avoid calling tlb_flush_mmu() */
+        }
+
+        batch = tlb->active;
+        batch->pages[batch->nr++] = page;
+        if (batch->nr == batch->max) {
+                if (!tlb_next_batch(tlb))
+                        return 0;
+        }
+        VM_BUG_ON(batch->nr > batch->max);
+
+        return batch->max - batch->nr;
+}
+
+#endif /* HAVE_GENERIC_MMU_GATHER */
+
 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 
 /*
@@ -268,7 +388,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table)
                 tlb_table_flush(tlb);
 }
 
-#endif
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
 
 /*
  * If a p?d_bad entry is found while walking page tables, report