6 files changed, 44 insertions, 6 deletions

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 32b0809203dd..4ac2c25025ea 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -55,3 +55,9 @@ Date:		January 2014
 Contact:        "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
 Description:
                  Controls the number of trials to find a victim segment.
+
+What:           /sys/fs/f2fs/<disk>/ram_thresh
+Date:           March 2014
+Contact:        "Jaegeuk Kim" <jaegeuk.kim@samsung.com>
+Description:
+                 Controls the memory footprint used by f2fs.
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 803784e1e8ef..f415b9fc4cc8 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -202,6 +202,10 @@ Files in /sys/fs/f2fs/<devname>
                               Otherwise, it needs to decrease this value to
                               reduce the space overhead. The default value is 0.
 
+ ram_thresh                   This parameter controls the memory footprint used
+                              by free nids and cached nat entries. By default,
+                              10 is set, which indicates 10 MB / 1 GB RAM.
+
 ================================================================================
 USAGE
 ================================================================================
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 59fac1a9f0c2..05c652493f04 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -242,6 +242,7 @@ struct f2fs_nm_info {
         block_t nat_blkaddr;            /* base disk address of NAT */
         nid_t max_nid;                  /* maximum possible node ids */
         nid_t next_scan_nid;            /* the next nid to be scanned */
+        unsigned int ram_thresh;        /* control the memory footprint */
 
         /* NAT cache management */
         struct radix_tree_root nat_root;/* root of the nat entry cache */
diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index d27e65a1fb0b..fec4967fb8d2 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -26,6 +26,22 @@
 static struct kmem_cache *nat_entry_slab;
 static struct kmem_cache *free_nid_slab;
 
+static inline bool available_free_memory(struct f2fs_nm_info *nm_i, int type)
+{
+        struct sysinfo val;
+        unsigned long mem_size = 0;
+
+        si_meminfo(&val);
+        if (type == FREE_NIDS)
+                mem_size = nm_i->fcnt * sizeof(struct free_nid);
+        else if (type == NAT_ENTRIES)
+                mem_size += nm_i->nat_cnt * sizeof(struct nat_entry);
+        mem_size >>= 12;
+
+        /* give 50:50 memory for free nids and nat caches respectively */
+        return (mem_size < ((val.totalram * nm_i->ram_thresh) >> 11));
+}
+
 static void clear_node_page_dirty(struct page *page)
 {
         struct address_space *mapping = page->mapping;
@@ -208,7 +224,7 @@ int try_to_free_nats(struct f2fs_sb_info *sbi, int nr_shrink)
 {
         struct f2fs_nm_info *nm_i = NM_I(sbi);
 
-        if (nm_i->nat_cnt <= NM_WOUT_THRESHOLD || nr_shrink <= 0)
+        if (available_free_memory(nm_i, NAT_ENTRIES) || nr_shrink <= 0)
                 return 0;
 
         write_lock(&nm_i->nat_tree_lock);
@@ -1288,7 +1304,7 @@ static int add_free_nid(struct f2fs_nm_info *nm_i, nid_t nid, bool build)
         struct nat_entry *ne;
         bool allocated = false;
 
-        if (nm_i->fcnt > 2 * MAX_FREE_NIDS)
+        if (!available_free_memory(nm_i, FREE_NIDS))
                 return -1;
 
         /* 0 nid should not be used */
@@ -1473,7 +1489,7 @@ void alloc_nid_failed(struct f2fs_sb_info *sbi, nid_t nid)
         spin_lock(&nm_i->free_nid_list_lock);
         i = __lookup_free_nid_list(nm_i, nid);
         f2fs_bug_on(!i || i->state != NID_ALLOC);
-        if (nm_i->fcnt > 2 * MAX_FREE_NIDS) {
+        if (!available_free_memory(nm_i, FREE_NIDS)) {
                 __del_from_free_nid_list(nm_i, i);
         } else {
                 i->state = NID_NEW;
@@ -1836,6 +1852,7 @@ static int init_node_manager(struct f2fs_sb_info *sbi)
         nm_i->max_nid = NAT_ENTRY_PER_BLOCK * nat_blocks - 3;
         nm_i->fcnt = 0;
         nm_i->nat_cnt = 0;
+        nm_i->ram_thresh = DEF_RAM_THRESHOLD;
 
         INIT_RADIX_TREE(&nm_i->free_nid_root, GFP_ATOMIC);
         INIT_LIST_HEAD(&nm_i->free_nid_list);
diff --git a/fs/f2fs/node.h b/fs/f2fs/node.h
index ee6d28684ee8..c97215432100 100644
--- a/fs/f2fs/node.h
+++ b/fs/f2fs/node.h
@@ -17,15 +17,15 @@
 /* # of pages to perform readahead before building free nids */
 #define FREE_NID_PAGES 4
 
-/* maximum # of free node ids to produce during build_free_nids */
-#define MAX_FREE_NIDS (NAT_ENTRY_PER_BLOCK * FREE_NID_PAGES)
-
 /* maximum readahead size for node during getting data blocks */
 #define MAX_RA_NODE             128
 
 /* maximum cached nat entries to manage memory footprint */
 #define NM_WOUT_THRESHOLD       (64 * NAT_ENTRY_PER_BLOCK)
 
+/* control the memory footprint threshold (10MB per 1GB ram) */
+#define DEF_RAM_THRESHOLD       10
+
 /* vector size for gang look-up from nat cache that consists of radix tree */
 #define NATVEC_SIZE     64
 
@@ -77,6 +77,11 @@ static inline void node_info_from_raw_nat(struct node_info *ni,
         ni->version = raw_ne->version;
 }
 
+enum nid_type {
+        FREE_NIDS,      /* indicates the free nid list */
+        NAT_ENTRIES     /* indicates the cached nat entry */
+};
+
 /*
  * For free nid mangement
  */
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index dbe402b1a4b7..34c47b2010bc 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -74,6 +74,7 @@ static match_table_t f2fs_tokens = {
 enum {
         GC_THREAD,      /* struct f2fs_gc_thread */
         SM_INFO,        /* struct f2fs_sm_info */
+        NM_INFO,        /* struct f2fs_nm_info */
         F2FS_SBI,       /* struct f2fs_sb_info */
 };
 
@@ -92,6 +93,8 @@ static unsigned char *__struct_ptr(struct f2fs_sb_info *sbi, int struct_type)
                 return (unsigned char *)sbi->gc_thread;
         else if (struct_type == SM_INFO)
                 return (unsigned char *)SM_I(sbi);
+        else if (struct_type == NM_INFO)
+                return (unsigned char *)NM_I(sbi);
         else if (struct_type == F2FS_SBI)
                 return (unsigned char *)sbi;
         return NULL;
@@ -183,6 +186,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, max_small_discards, max_discards);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
 F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util);
+F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, max_victim_search, max_victim_search);
 F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, dir_level, dir_level);
 
@@ -198,6 +202,7 @@ static struct attribute *f2fs_attrs[] = {
         ATTR_LIST(min_ipu_util),
         ATTR_LIST(max_victim_search),
         ATTR_LIST(dir_level),
+        ATTR_LIST(ram_thresh),
         NULL,
 };