8 files changed, 143 insertions, 22 deletions

diff --git a/mm/Makefile b/mm/Makefile
index 98c4eaeabdcb..98d28edd36a5 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -56,7 +56,7 @@ obj-$(CONFIG_KASAN)	+= kasan/
 obj-$(CONFIG_FAILSLAB) += failslab.o
 obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
 obj-$(CONFIG_MEMTEST)           += memtest.o
-obj-$(CONFIG_MIGRATION) += migrate.o
+obj-$(CONFIG_MIGRATION) += migrate.o replication.o
 obj-$(CONFIG_QUICKLIST) += quicklist.o
 obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o
 obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
diff --git a/mm/debug.c b/mm/debug.c
index 3eb3ac2fcee7..dbc3ea81dde7 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -36,6 +36,7 @@ static const struct trace_print_flags pageflag_names[] = {
         {1UL << PG_reclaim,             "reclaim"       },
         {1UL << PG_swapbacked,          "swapbacked"    },
         {1UL << PG_unevictable,         "unevictable"   },
+        {1UL << PG_replicated,          "replicated"    },
 #ifdef CONFIG_MMU
         {1UL << PG_mlocked,             "mlocked"       },
 #endif
diff --git a/mm/filemap.c b/mm/filemap.c
index 8ea609718839..93853e337f07 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -973,13 +973,21 @@ repeat:
         page = NULL;
         pagep = radix_tree_lookup_slot(&mapping->page_tree, offset);
         if (pagep) {
-                void *pdesc;
-                pdesc = radix_tree_deref_slot(pagep);
-                if (pdesc)
-                        page = (struct page*)pdesc;
-                //page = radix_tree_deref_slot(pagep);
+                page = radix_tree_deref_slot(pagep);
                 if (unlikely(!page))
                         goto out;
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+printk(KERN_INFO "PCACHE_DESC\n");
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+                        
+                        unreplicate_pcache(mapping, page->index, 0);
+                        
+                        goto out;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 goto repeat;
@@ -1178,6 +1186,20 @@ repeat:
                 page = radix_tree_deref_slot(slot);
                 if (unlikely(!page))
                         continue;
+                
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+                        printk(KERN_INFO "PCACHE_DESC\n");
+                        
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+                        
+                        unreplicate_pcache(mapping, page->index, 0);
+                        
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 goto restart;
@@ -1241,6 +1263,20 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1268,6 +1304,7 @@ repeat:
                         goto repeat;
                 }
 
+export:
                 pages[ret] = page;
                 if (++ret == nr_pages)
                         break;
@@ -1309,6 +1346,20 @@ repeat:
                 if (unlikely(!page))
                         break;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1334,7 +1385,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 /*
                  * must check mapping and index after taking the ref.
                  * otherwise we can get both false positives and false
@@ -1385,6 +1436,20 @@ repeat:
                 if (unlikely(!page))
                         continue;
 
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+                        printk(KERN_INFO "PCACHE_DESC BUG!!!!!!!!!!\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        page_cache_get_speculative(page);
+
+                        unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page)) {
                                 /*
@@ -1416,7 +1481,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 pages[ret] = page;
                 if (++ret == nr_pages)
                         break;
@@ -1492,7 +1557,11 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos,
 
                 cond_resched();
 find_page:
-                page = find_get_page(mapping, index);
+                if (is_realtime(current))
+                        page = find_get_page_readonly(mapping, index);
+                else
+                        page = find_get_page(mapping, index);
+                
                 if (!page) {
                         page_cache_sync_readahead(mapping,
                                         ra, filp,
@@ -1644,7 +1713,8 @@ readpage:
                         unlock_page(page);
                 }
 
-                goto page_ok;
+                page_cache_release(page);
+                goto find_page;
 
 readpage_error:
                 /* UHHUH! A synchronous read error occurred. Report it */
@@ -1888,9 +1958,11 @@ int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
         /*
          * Do we have something in the page cache already?
          */
-if (is_realtime(current))
-        printk("FILEMAP_FAULT %ld\n", vma->vm_start);
-        page = find_get_page(mapping, offset);
+        if ((vmf->flags & FAULT_FLAG_WRITE) || !is_realtime(current))
+                page = find_get_page(mapping, offset);
+        else
+                page = find_get_page_readonly(mapping, offset);
+        
         if (likely(page) && !(vmf->flags & FAULT_FLAG_TRIED)) {
                 /*
                  * We found the page, so try async readahead before
@@ -1904,7 +1976,10 @@ if (is_realtime(current))
                 mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
                 ret = VM_FAULT_MAJOR;
 retry_find:
-                page = find_get_page(mapping, offset);
+                if ((vmf->flags & FAULT_FLAG_WRITE) || !is_realtime(current))
+                        page = find_get_page(mapping, offset);
+                else
+                        page = find_get_page_readonly(mapping, offset);
                 if (!page)
                         goto no_cached_page;
         }
@@ -2012,6 +2087,22 @@ repeat:
                 page = radix_tree_deref_slot(slot);
                 if (unlikely(!page))
                         goto next;
+                
+                if (is_pcache_desc(page)) {
+                        struct pcache_desc *pcd;
+
+printk(KERN_INFO "PCACHE_DESC FILE_MAP_PAGES\n");
+
+                        pcd = ptr_to_pcache_desc(page);
+                        page = pcd->master;
+                        if (!page_cache_get_speculative(page))
+                                goto repeat;
+                        
+                        //unreplicate_pcache(mapping, page->index, 0);
+
+                        goto export;
+                }
+                
                 if (radix_tree_exception(page)) {
                         if (radix_tree_deref_retry(page))
                                 break;
@@ -2027,7 +2118,7 @@ repeat:
                         page_cache_release(page);
                         goto repeat;
                 }
-
+export:
                 if (!PageUptodate(page) ||
                                 PageReadahead(page) ||
                                 PageHWPoison(page))
diff --git a/mm/internal.h b/mm/internal.h
index a25e359a4039..ccc349b59d00 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -433,4 +433,14 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
 #define ALLOC_CMA               0x80 /* allow allocations from CMA areas */
 #define ALLOC_FAIR              0x100 /* fair zone allocation */
 
+extern int reclaim_replicated_page(struct address_space *mapping,
+                struct page *page);
+extern struct page *find_get_page_readonly(struct address_space *mapping,
+                                                unsigned long offset);
+extern int is_pcache_desc(void *ptr);
+extern struct pcache_desc *ptr_to_pcache_desc(void *ptr);
+extern void *pcache_desc_to_ptr(struct pcache_desc *pcd);
+extern void unreplicate_pcache(struct address_space *mapping, unsigned long offset, int locked);
+int page_write_fault_retry(struct page *page);
+
 #endif  /* __MM_INTERNAL_H */
diff --git a/mm/memory.c b/mm/memory.c
index 22e037e3364e..1fc358bec6d5 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2231,15 +2231,24 @@ static int wp_page_shared(struct mm_struct *mm, struct vm_area_struct *vma,
          * read-only shared pages can get COWed by
          * get_user_pages(.write=1, .force=1).
          */
-        if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+//      if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+        {
                 int tmp;
 
                 pte_unmap_unlock(page_table, ptl);
-                tmp = do_page_mkwrite(vma, old_page, address);
-                if (unlikely(!tmp || (tmp &
-                                      (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
+                
+                if (page_write_fault_retry(old_page)) {
                         page_cache_release(old_page);
-                        return tmp;
+                        return 0;
+                }
+                
+                if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
+                        tmp = do_page_mkwrite(vma, old_page, address);
+                        if (unlikely(!tmp || (tmp &
+                                                  (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
+                                page_cache_release(old_page);
+                                return tmp;
+                        }
                 }
                 /*
                  * Since we dropped the lock we need to revalidate
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 7e39ffceb566..161af608b7e2 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -2287,7 +2287,8 @@ int clear_page_dirty_for_io(struct page *page)
 
         BUG_ON(!PageLocked(page));
 
-        if (mapping && mapping_cap_account_dirty(mapping)) {
+        //if (mapping && mapping_cap_account_dirty(mapping)) {
+        if (mapping) {
                 /*
                  * Yes, Virginia, this is indeed insane.
                  *
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5e8eadd71bac..b9b6bef90169 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -582,6 +582,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
         BUG_ON(!PageLocked(page));
         BUG_ON(mapping != page_mapping(page));
 
+again:
         spin_lock_irq(&mapping->tree_lock);
         /*
          * The non racy check for a busy page.
@@ -640,7 +641,11 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
                 if (reclaimed && page_is_file_cache(page) &&
                     !mapping_exiting(mapping))
                         shadow = workingset_eviction(mapping, page);
-                __delete_from_page_cache(page, shadow);
+                if (PageReplicated(page)) {
+                        if (reclaim_replicated_page(mapping, page))
+                                goto again;
+                } else
+                        __delete_from_page_cache(page, shadow);
                 spin_unlock_irq(&mapping->tree_lock);
 
                 if (freepage != NULL)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 4f5cd974e11a..6af8ea00cbef 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -708,6 +708,7 @@ const char * const vmstat_text[] = {
         "nr_anon_pages",
         "nr_mapped",
         "nr_file_pages",
+        "nr_repl_pages",
         "nr_dirty",
         "nr_writeback",
         "nr_slab_reclaimable",
@@ -760,6 +761,9 @@ const char * const vmstat_text[] = {
         "pgfault",
         "pgmajfault",
 
+        "pgreplicated",
+        "pgreplicazap",
+        
         TEXTS_FOR_ZONES("pgrefill")
         TEXTS_FOR_ZONES("pgsteal_kswapd")
         TEXTS_FOR_ZONES("pgsteal_direct")