f2fs: split free nid list

During free nid allocation, in order to do preallocation, we will tag free
nid entry as allocated one and still leave it in free nid list, for other
allocators who want to grab free nids, it needs to traverse the free nid
list for lookup. It becomes overhead in scenario of allocating free nid
intensively by multithreads.

This patch splits free nid list to two list: {free,alloc}_nid_list, to
keep free nids and preallocated free nids separately, after that, traverse
latency will be gone, besides split nid_cnt for separate statistic.

Additionally, introduce __insert_nid_to_list and __remove_nid_from_list for
cleanup.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: modify f2fs_bug_on to avoid needless branches]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 7 insertions, 4 deletions

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index fb245bd302e4..6af146c48644 100644
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -74,7 +74,8 @@ static void update_general_status(struct f2fs_sb_info *sbi)
         si->dirty_nats = NM_I(sbi)->dirty_nat_cnt;
         si->sits = MAIN_SEGS(sbi);
         si->dirty_sits = SIT_I(sbi)->dirty_sentries;
-        si->fnids = NM_I(sbi)->fcnt;
+        si->free_nids = NM_I(sbi)->nid_cnt[FREE_NID_LIST];
+        si->alloc_nids = NM_I(sbi)->nid_cnt[ALLOC_NID_LIST];
         si->bg_gc = sbi->bg_gc;
         si->util_free = (int)(free_user_blocks(sbi) >> sbi->log_blocks_per_seg)
                 * 100 / (int)(sbi->user_block_count >> sbi->log_blocks_per_seg)
@@ -194,7 +195,9 @@ get_cache:
                 si->cache_mem += sizeof(struct flush_cmd_control);
 
         /* free nids */
-        si->cache_mem += NM_I(sbi)->fcnt * sizeof(struct free_nid);
+        si->cache_mem += (NM_I(sbi)->nid_cnt[FREE_NID_LIST] +
+                                NM_I(sbi)->nid_cnt[ALLOC_NID_LIST]) *
+                                sizeof(struct free_nid);
         si->cache_mem += NM_I(sbi)->nat_cnt * sizeof(struct nat_entry);
         si->cache_mem += NM_I(sbi)->dirty_nat_cnt *
                                         sizeof(struct nat_entry_set);
@@ -324,8 +327,8 @@ static int stat_show(struct seq_file *s, void *v)
                            si->ndirty_imeta);
                 seq_printf(s, "  - NATs: %9d/%9d\n  - SITs: %9d/%9d\n",
                            si->dirty_nats, si->nats, si->dirty_sits, si->sits);
-                seq_printf(s, "  - free_nids: %9d\n",
-                           si->fnids);
+                seq_printf(s, "  - free_nids: %9d, alloc_nids: %9d\n",
+                           si->free_nids, si->alloc_nids);
                 seq_puts(s, "\nDistribution of User Blocks:");
                 seq_puts(s, " [ valid | invalid | free ]\n");
                 seq_puts(s, "  [");