f2fs: separate nat entry mem alloc from nat_tree_lock

This patch splits memory allocation part in nat_entry to avoid lock contention.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 9abfdbb..fe1fc66 100644 (file)
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -138,6 +138,44 @@ static struct page *get_next_nat_page(struct f2fs_sb_info *sbi, nid_t nid)
        return dst_page;
 }
 
+static struct nat_entry *__alloc_nat_entry(nid_t nid, bool no_fail)
+{
+       struct nat_entry *new;
+
+       if (no_fail)
+               new = f2fs_kmem_cache_alloc(nat_entry_slab,
+                                               GFP_NOFS | __GFP_ZERO);
+       else
+               new = kmem_cache_alloc(nat_entry_slab,
+                                               GFP_NOFS | __GFP_ZERO);
+       if (new) {
+               nat_set_nid(new, nid);
+               nat_reset_flag(new);
+       }
+       return new;
+}
+
+static void __free_nat_entry(struct nat_entry *e)
+{
+       kmem_cache_free(nat_entry_slab, e);
+}
+
+/* must be locked by nat_tree_lock */
+static struct nat_entry *__init_nat_entry(struct f2fs_nm_info *nm_i,
+       struct nat_entry *ne, struct f2fs_nat_entry *raw_ne, bool no_fail)
+{
+       if (no_fail)
+               f2fs_radix_tree_insert(&nm_i->nat_root, nat_get_nid(ne), ne);
+       else if (radix_tree_insert(&nm_i->nat_root, nat_get_nid(ne), ne))
+               return NULL;
+
+       if (raw_ne)
+               node_info_from_raw_nat(&ne->ni, raw_ne);
+       list_add_tail(&ne->list, &nm_i->nat_entries);
+       nm_i->nat_cnt++;
+       return ne;
+}
+
 static struct nat_entry *__lookup_nat_cache(struct f2fs_nm_info *nm_i, nid_t n)
 {
        return radix_tree_lookup(&nm_i->nat_root, n);
@@ -154,7 +192,7 @@ static void __del_from_nat_cache(struct f2fs_nm_info *nm_i, struct nat_entry *e)
        list_del(&e->list);
        radix_tree_delete(&nm_i->nat_root, nat_get_nid(e));
        nm_i->nat_cnt--;
-       kmem_cache_free(nat_entry_slab, e);
+       __free_nat_entry(e);
 }
 
 static void __set_nat_cache_dirty(struct f2fs_nm_info *nm_i,
@@ -250,49 +288,29 @@ bool need_inode_block_update(struct f2fs_sb_info *sbi, nid_t ino)
        return need_update;
 }
 
-static struct nat_entry *grab_nat_entry(struct f2fs_nm_info *nm_i, nid_t nid,
-                                                               bool no_fail)
-{
-       struct nat_entry *new;
-
-       if (no_fail) {
-               new = f2fs_kmem_cache_alloc(nat_entry_slab, GFP_NOFS);
-               f2fs_radix_tree_insert(&nm_i->nat_root, nid, new);
-       } else {
-               new = kmem_cache_alloc(nat_entry_slab, GFP_NOFS);
-               if (!new)
-                       return NULL;
-               if (radix_tree_insert(&nm_i->nat_root, nid, new)) {
-                       kmem_cache_free(nat_entry_slab, new);
-                       return NULL;
-               }
-       }
-
-       memset(new, 0, sizeof(struct nat_entry));
-       nat_set_nid(new, nid);
-       nat_reset_flag(new);
-       list_add_tail(&new->list, &nm_i->nat_entries);
-       nm_i->nat_cnt++;
-       return new;
-}
-
+/* must be locked by nat_tree_lock */
 static void cache_nat_entry(struct f2fs_sb_info *sbi, nid_t nid,
                                                struct f2fs_nat_entry *ne)
 {
        struct f2fs_nm_info *nm_i = NM_I(sbi);
-       struct nat_entry *e;
+       struct nat_entry *new, *e;
 
+       new = __alloc_nat_entry(nid, false);
+       if (!new)
+               return;
+
+       down_write(&nm_i->nat_tree_lock);
        e = __lookup_nat_cache(nm_i, nid);
-       if (!e) {
-               e = grab_nat_entry(nm_i, nid, false);
-               if (e)
-                       node_info_from_raw_nat(&e->ni, ne);
-       } else {
+       if (!e)
+               e = __init_nat_entry(nm_i, new, ne, false);
+       else
                f2fs_bug_on(sbi, nat_get_ino(e) != le32_to_cpu(ne->ino) ||
                                nat_get_blkaddr(e) !=
                                        le32_to_cpu(ne->block_addr) ||
                                nat_get_version(e) != ne->version);
-       }
+       up_write(&nm_i->nat_tree_lock);
+       if (e != new)
+               __free_nat_entry(new);
 }
 
 static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
@@ -300,11 +318,12 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
 {
        struct f2fs_nm_info *nm_i = NM_I(sbi);
        struct nat_entry *e;
+       struct nat_entry *new = __alloc_nat_entry(ni->nid, true);
 
        down_write(&nm_i->nat_tree_lock);
        e = __lookup_nat_cache(nm_i, ni->nid);
        if (!e) {
-               e = grab_nat_entry(nm_i, ni->nid, true);
+               e = __init_nat_entry(nm_i, new, NULL, true);
                copy_node_info(&e->ni, ni);
                f2fs_bug_on(sbi, ni->blk_addr == NEW_ADDR);
        } else if (new_blkaddr == NEW_ADDR) {
@@ -316,6 +335,9 @@ static void set_node_addr(struct f2fs_sb_info *sbi, struct node_info *ni,
                copy_node_info(&e->ni, ni);
                f2fs_bug_on(sbi, ni->blk_addr != NULL_ADDR);
        }
+       /* let's free early to reduce memory consumption */
+       if (e != new)
+               __free_nat_entry(new);
 
        /* sanity check */
        f2fs_bug_on(sbi, nat_get_blkaddr(e) != ni->blk_addr);
@@ -424,9 +446,7 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni)
        f2fs_put_page(page, 1);
 cache:
        /* cache nat entry */
-       down_write(&nm_i->nat_tree_lock);
        cache_nat_entry(sbi, nid, &ne);
-       up_write(&nm_i->nat_tree_lock);
 }
 
 /*
@@ -2374,8 +2394,8 @@ static void remove_nats_in_journal(struct f2fs_sb_info *sbi)
 
                ne = __lookup_nat_cache(nm_i, nid);
                if (!ne) {
-                       ne = grab_nat_entry(nm_i, nid, true);
-                       node_info_from_raw_nat(&ne->ni, &raw_ne);
+                       ne = __alloc_nat_entry(nid, true);
+                       __init_nat_entry(nm_i, ne, &raw_ne, true);
                }
 
                /*