[PATCH] ZVC: Support NR_SLAB_RECLAIMABLE / NR_SLAB_UNRECLAIMABLE

Remove the atomic counter for slab_reclaim_pages and replace the counter
and NR_SLAB with two ZVC counter that account for unreclaimable and
reclaimable slab pages: NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE.

Change the check in vmscan.c to refer to to NR_SLAB_RECLAIMABLE.  The
intend seems to be to check for slab pages that could be freed.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

12 files changed, 36 insertions, 29 deletions

diff --git a/arch/i386/mm/pgtable.c b/arch/i386/mm/pgtable.c
index bd98768d8764..a9f4910a22f8 100644
--- a/arch/i386/mm/pgtable.c
+++ b/arch/i386/mm/pgtable.c
@@ -60,7 +60,9 @@ void show_mem(void)
         printk(KERN_INFO "%lu pages writeback\n",
                                         global_page_state(NR_WRITEBACK));
         printk(KERN_INFO "%lu pages mapped\n", global_page_state(NR_FILE_MAPPED));
-        printk(KERN_INFO "%lu pages slab\n", global_page_state(NR_SLAB));
+        printk(KERN_INFO "%lu pages slab\n",
+                global_page_state(NR_SLAB_RECLAIMABLE) +
+                global_page_state(NR_SLAB_UNRECLAIMABLE));
         printk(KERN_INFO "%lu pages pagetables\n",
                                         global_page_state(NR_PAGETABLE));
 }
diff --git a/drivers/base/node.c b/drivers/base/node.c
index e09f5c2c11ee..001e6f6b9c1b 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -68,7 +68,9 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
                        "Node %d PageTables:   %8lu kB\n"
                        "Node %d NFS_Unstable: %8lu kB\n"
                        "Node %d Bounce:       %8lu kB\n"
-                       "Node %d Slab:         %8lu kB\n",
+                       "Node %d Slab:         %8lu kB\n"
+                       "Node %d SReclaimable: %8lu kB\n"
+                       "Node %d SUnreclaim:   %8lu kB\n",
                        nid, K(i.totalram),
                        nid, K(i.freeram),
                        nid, K(i.totalram - i.freeram),
@@ -88,7 +90,10 @@ static ssize_t node_read_meminfo(struct sys_device * dev, char * buf)
                        nid, K(node_page_state(nid, NR_PAGETABLE)),
                        nid, K(node_page_state(nid, NR_UNSTABLE_NFS)),
                        nid, K(node_page_state(nid, NR_BOUNCE)),
-                       nid, K(node_page_state(nid, NR_SLAB)));
+                       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE) +
+                                node_page_state(nid, NR_SLAB_UNRECLAIMABLE)),
+                       nid, K(node_page_state(nid, NR_SLAB_RECLAIMABLE)),
+                       nid, K(node_page_state(nid, NR_SLAB_UNRECLAIMABLE)));
         n += hugetlb_report_node_meminfo(nid, buf + n);
         return n;
 }
diff --git a/fs/proc/proc_misc.c b/fs/proc/proc_misc.c
index caa0a51560a0..5bbd60896050 100644
--- a/fs/proc/proc_misc.c
+++ b/fs/proc/proc_misc.c
@@ -170,6 +170,8 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
                 "AnonPages:    %8lu kB\n"
                 "Mapped:       %8lu kB\n"
                 "Slab:         %8lu kB\n"
+                "SReclaimable: %8lu kB\n"
+                "SUnreclaim:   %8lu kB\n"
                 "PageTables:   %8lu kB\n"
                 "NFS_Unstable: %8lu kB\n"
                 "Bounce:       %8lu kB\n"
@@ -197,7 +199,10 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
                 K(global_page_state(NR_WRITEBACK)),
                 K(global_page_state(NR_ANON_PAGES)),
                 K(global_page_state(NR_FILE_MAPPED)),
-                K(global_page_state(NR_SLAB)),
+                K(global_page_state(NR_SLAB_RECLAIMABLE) +
+                                global_page_state(NR_SLAB_UNRECLAIMABLE)),
+                K(global_page_state(NR_SLAB_RECLAIMABLE)),
+                K(global_page_state(NR_SLAB_UNRECLAIMABLE)),
                 K(global_page_state(NR_PAGETABLE)),
                 K(global_page_state(NR_UNSTABLE_NFS)),
                 K(global_page_state(NR_BOUNCE)),
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a703527e2b45..08c41b9f92e0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -51,7 +51,8 @@ enum zone_stat_item {
         NR_FILE_MAPPED, /* pagecache pages mapped into pagetables.
                            only modified from process context */
         NR_FILE_PAGES,
-        NR_SLAB,        /* Pages used by slab allocator */
+        NR_SLAB_RECLAIMABLE,
+        NR_SLAB_UNRECLAIMABLE,
         NR_PAGETABLE,   /* used for pagetables */
         NR_FILE_DIRTY,
         NR_WRITEBACK,
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 2f6bef6a98c9..66d6eb78d1c6 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -284,8 +284,6 @@ extern kmem_cache_t	*fs_cachep;
 extern kmem_cache_t     *sighand_cachep;
 extern kmem_cache_t     *bio_cachep;
 
-extern atomic_t slab_reclaim_pages;
-
 #endif  /* __KERNEL__ */
 
 #endif  /* _LINUX_SLAB_H */
diff --git a/mm/mmap.c b/mm/mmap.c
index 8507ee9cd573..eea8eefd51a8 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -116,7 +116,7 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
                  * which are reclaimable, under pressure.  The dentry
                  * cache and most inode caches should fall into this
                  */
-                free += atomic_read(&slab_reclaim_pages);
+                free += global_page_state(NR_SLAB_RECLAIMABLE);
 
                 /*
                  * Leave the last 3% for root
diff --git a/mm/nommu.c b/mm/nommu.c
index c576df71e3bb..d99dea31e443 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1133,7 +1133,7 @@ int __vm_enough_memory(long pages, int cap_sys_admin)
                  * which are reclaimable, under pressure.  The dentry
                  * cache and most inode caches should fall into this
                  */
-                free += atomic_read(&slab_reclaim_pages);
+                free += global_page_state(NR_SLAB_RECLAIMABLE);
 
                 /*
                  * Leave the last 3% for root
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 5da6bc4e0a6b..47e98423b30d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1304,7 +1304,8 @@ void show_free_areas(void)
                 global_page_state(NR_WRITEBACK),
                 global_page_state(NR_UNSTABLE_NFS),
                 nr_free_pages(),
-                global_page_state(NR_SLAB),
+                global_page_state(NR_SLAB_RECLAIMABLE) +
+                        global_page_state(NR_SLAB_UNRECLAIMABLE),
                 global_page_state(NR_FILE_MAPPED),
                 global_page_state(NR_PAGETABLE));
 
diff --git a/mm/slab.c b/mm/slab.c
index 13b5050f84cc..7a48eb1a60c8 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -736,14 +736,6 @@ static DEFINE_MUTEX(cache_chain_mutex);
 static struct list_head cache_chain;
 
 /*
- * vm_enough_memory() looks at this to determine how many slab-allocated pages
- * are possibly freeable under pressure
- *
- * SLAB_RECLAIM_ACCOUNT turns this on per-slab
- */
-atomic_t slab_reclaim_pages;
-
-/*
  * chicken and egg problem: delay the per-cpu array allocation
  * until the general caches are up.
  */
@@ -1580,8 +1572,11 @@ static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 
         nr_pages = (1 << cachep->gfporder);
         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
-                atomic_add(nr_pages, &slab_reclaim_pages);
-        add_zone_page_state(page_zone(page), NR_SLAB, nr_pages);
+                add_zone_page_state(page_zone(page),
+                        NR_SLAB_RECLAIMABLE, nr_pages);
+        else
+                add_zone_page_state(page_zone(page),
+                        NR_SLAB_UNRECLAIMABLE, nr_pages);
         for (i = 0; i < nr_pages; i++)
                 __SetPageSlab(page + i);
         return page_address(page);
@@ -1596,7 +1591,12 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
         struct page *page = virt_to_page(addr);
         const unsigned long nr_freed = i;
 
-        sub_zone_page_state(page_zone(page), NR_SLAB, nr_freed);
+        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
+                sub_zone_page_state(page_zone(page),
+                                NR_SLAB_RECLAIMABLE, nr_freed);
+        else
+                sub_zone_page_state(page_zone(page),
+                                NR_SLAB_UNRECLAIMABLE, nr_freed);
         while (i--) {
                 BUG_ON(!PageSlab(page));
                 __ClearPageSlab(page);
@@ -1605,8 +1605,6 @@ static void kmem_freepages(struct kmem_cache *cachep, void *addr)
         if (current->reclaim_state)
                 current->reclaim_state->reclaimed_slab += nr_freed;
         free_pages((unsigned long)addr, cachep->gfporder);
-        if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
-                atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
 }
 
 static void kmem_rcu_free(struct rcu_head *head)
diff --git a/mm/slob.c b/mm/slob.c
index 4c28a421b270..20188627347c 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -339,7 +339,3 @@ void kmem_cache_init(void)
 
         mod_timer(&slob_timer, jiffies + HZ);
 }
-
-atomic_t slab_reclaim_pages = ATOMIC_INIT(0);
-EXPORT_SYMBOL(slab_reclaim_pages);
-
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 5154c25e8440..349797ba4bac 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1378,7 +1378,7 @@ unsigned long shrink_all_memory(unsigned long nr_pages)
         for_each_zone(zone)
                 lru_pages += zone->nr_active + zone->nr_inactive;
 
-        nr_slab = global_page_state(NR_SLAB);
+        nr_slab = global_page_state(NR_SLAB_RECLAIMABLE);
         /* If slab caches are huge, it's better to hit them first */
         while (nr_slab >= lru_pages) {
                 reclaim_state.reclaimed_slab = 0;
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 968c0072e19a..490d8c1a0ded 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -458,7 +458,8 @@ static char *vmstat_text[] = {
         "nr_anon_pages",
         "nr_mapped",
         "nr_file_pages",
-        "nr_slab",
+        "nr_slab_reclaimable",
+        "nr_slab_unreclaimable",
         "nr_page_table_pages",
         "nr_dirty",
         "nr_writeback",