f2fs: add to account skip count of background GC

This patch adds to account skip count of background GC, and show stat
info via 'status' debugfs entry.

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

diff --git a/fs/f2fs/debug.c b/fs/f2fs/debug.c
index da1cabb..75bc62e 100644 (file)
--- a/fs/f2fs/debug.c
+++ b/fs/f2fs/debug.c
@@ -101,6 +101,8 @@ static void update_general_status(struct f2fs_sb_info *sbi)
        si->avail_nids = NM_I(sbi)->available_nids;
        si->alloc_nids = NM_I(sbi)->nid_cnt[PREALLOC_NID];
        si->bg_gc = sbi->bg_gc;
+       si->io_skip_bggc = sbi->io_skip_bggc;
+       si->other_skip_bggc = sbi->other_skip_bggc;
        si->skipped_atomic_files[BG_GC] = sbi->skipped_atomic_files[BG_GC];
        si->skipped_atomic_files[FG_GC] = sbi->skipped_atomic_files[FG_GC];
        si->util_free = (int)(free_user_blocks(sbi) >> sbi->log_blocks_per_seg)
@@ -355,6 +357,8 @@ static int stat_show(struct seq_file *s, void *v)
                                si->skipped_atomic_files[BG_GC] +
                                si->skipped_atomic_files[FG_GC],
                                si->skipped_atomic_files[BG_GC]);
+               seq_printf(s, "BG skip : IO: %u, Other: %u\n",
+                               si->io_skip_bggc, si->other_skip_bggc);
                seq_puts(s, "\nExtent Cache:\n");
                seq_printf(s, "  - Hit Count: L1-1:%llu L1-2:%llu L2:%llu\n",
                                si->hit_largest, si->hit_cached,

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 46cdb53..1924367 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1277,6 +1277,8 @@ struct f2fs_sb_info {
        atomic_t max_aw_cnt;                    /* max # of atomic writes */
        atomic_t max_vw_cnt;                    /* max # of volatile writes */
        int bg_gc;                              /* background gc calls */
+       unsigned int io_skip_bggc;              /* skip background gc for in-flight IO */
+       unsigned int other_skip_bggc;           /* skip background gc for other reasons */
        unsigned int ndirty_inode[NR_INODE_TYPE];       /* # of dirty inodes */
 #endif
        spinlock_t stat_lock;                   /* lock for stat operations */
@@ -3104,6 +3106,7 @@ struct f2fs_stat_info {
        int free_nids, avail_nids, alloc_nids;
        int total_count, utilization;
        int bg_gc, nr_wb_cp_data, nr_wb_data;
+       unsigned int io_skip_bggc, other_skip_bggc;
        int nr_flushing, nr_flushed, flush_list_empty;
        int nr_discarding, nr_discarded;
        int nr_discard_cmd;
@@ -3141,6 +3144,8 @@ static inline struct f2fs_stat_info *F2FS_STAT(struct f2fs_sb_info *sbi)
 #define stat_inc_bg_cp_count(si)       ((si)->bg_cp_count++)
 #define stat_inc_call_count(si)                ((si)->call_count++)
 #define stat_inc_bggc_count(sbi)       ((sbi)->bg_gc++)
+#define stat_io_skip_bggc_count(sbi)   ((sbi)->io_skip_bggc++)
+#define stat_other_skip_bggc_count(sbi)        ((sbi)->other_skip_bggc++)
 #define stat_inc_dirty_inode(sbi, type)        ((sbi)->ndirty_inode[type]++)
 #define stat_dec_dirty_inode(sbi, type)        ((sbi)->ndirty_inode[type]--)
 #define stat_inc_total_hit(sbi)                (atomic64_inc(&(sbi)->total_hit_ext))
@@ -3257,6 +3262,8 @@ void f2fs_destroy_root_stats(void);
 #define stat_inc_bg_cp_count(si)                       do { } while (0)
 #define stat_inc_call_count(si)                                do { } while (0)
 #define stat_inc_bggc_count(si)                                do { } while (0)
+#define stat_io_skip_bggc_count(sbi)                   do { } while (0)
+#define stat_other_skip_bggc_count(sbi)                        do { } while (0)
 #define stat_inc_dirty_inode(sbi, type)                        do { } while (0)
 #define stat_dec_dirty_inode(sbi, type)                        do { } while (0)
 #define stat_inc_total_hit(sb)                         do { } while (0)

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index f541aa3..99ed8a5 100644 (file)
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -40,13 +40,16 @@ static int gc_thread_func(void *data)
                if (gc_th->gc_wake)
                        gc_th->gc_wake = 0;
 
-               if (try_to_freeze())
+               if (try_to_freeze()) {
+                       stat_other_skip_bggc_count(sbi);
                        continue;
+               }
                if (kthread_should_stop())
                        break;
 
                if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
                        increase_sleep_time(gc_th, &wait_ms);
+                       stat_other_skip_bggc_count(sbi);
                        continue;
                }
 
@@ -55,8 +58,10 @@ static int gc_thread_func(void *data)
                        f2fs_stop_checkpoint(sbi, false);
                }
 
-               if (!sb_start_write_trylock(sbi->sb))
+               if (!sb_start_write_trylock(sbi->sb)) {
+                       stat_other_skip_bggc_count(sbi);
                        continue;
+               }
 
                /*
                 * [GC triggering condition]
@@ -77,12 +82,15 @@ static int gc_thread_func(void *data)
                        goto do_gc;
                }
 
-               if (!mutex_trylock(&sbi->gc_mutex))
+               if (!mutex_trylock(&sbi->gc_mutex)) {
+                       stat_other_skip_bggc_count(sbi);
                        goto next;
+               }
 
                if (!is_idle(sbi, GC_TIME)) {
                        increase_sleep_time(gc_th, &wait_ms);
                        mutex_unlock(&sbi->gc_mutex);
+                       stat_io_skip_bggc_count(sbi);
                        goto next;
                }