File-copy from v4.4.100
This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Please refer to that tree for all history prior to this point.
Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
new file mode 100644
index 0000000..b4a65be
--- /dev/null
+++ b/fs/f2fs/gc.h
@@ -0,0 +1,110 @@
+/*
+ * fs/f2fs/gc.h
+ *
+ * Copyright (c) 2012 Samsung Electronics Co., Ltd.
+ * http://www.samsung.com/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#define GC_THREAD_MIN_WB_PAGES 1 /*
+ * a threshold to determine
+ * whether IO subsystem is idle
+ * or not
+ */
+#define DEF_GC_THREAD_MIN_SLEEP_TIME 30000 /* milliseconds */
+#define DEF_GC_THREAD_MAX_SLEEP_TIME 60000
+#define DEF_GC_THREAD_NOGC_SLEEP_TIME 300000 /* wait 5 min */
+#define LIMIT_INVALID_BLOCK 40 /* percentage over total user space */
+#define LIMIT_FREE_BLOCK 40 /* percentage over invalid + free space */
+
+/* Search max. number of dirty segments to select a victim segment */
+#define DEF_MAX_VICTIM_SEARCH 4096 /* covers 8GB */
+
+struct f2fs_gc_kthread {
+ struct task_struct *f2fs_gc_task;
+ wait_queue_head_t gc_wait_queue_head;
+
+ /* for gc sleep time */
+ unsigned int min_sleep_time;
+ unsigned int max_sleep_time;
+ unsigned int no_gc_sleep_time;
+
+ /* for changing gc mode */
+ unsigned int gc_idle;
+};
+
+struct gc_inode_list {
+ struct list_head ilist;
+ struct radix_tree_root iroot;
+};
+
+/*
+ * inline functions
+ */
+static inline block_t free_user_blocks(struct f2fs_sb_info *sbi)
+{
+ if (free_segments(sbi) < overprovision_segments(sbi))
+ return 0;
+ else
+ return (free_segments(sbi) - overprovision_segments(sbi))
+ << sbi->log_blocks_per_seg;
+}
+
+static inline block_t limit_invalid_user_blocks(struct f2fs_sb_info *sbi)
+{
+ return (long)(sbi->user_block_count * LIMIT_INVALID_BLOCK) / 100;
+}
+
+static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
+{
+ block_t reclaimable_user_blocks = sbi->user_block_count -
+ written_block_count(sbi);
+ return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
+}
+
+static inline void increase_sleep_time(struct f2fs_gc_kthread *gc_th,
+ long *wait)
+{
+ if (*wait == gc_th->no_gc_sleep_time)
+ return;
+
+ *wait += gc_th->min_sleep_time;
+ if (*wait > gc_th->max_sleep_time)
+ *wait = gc_th->max_sleep_time;
+}
+
+static inline void decrease_sleep_time(struct f2fs_gc_kthread *gc_th,
+ long *wait)
+{
+ if (*wait == gc_th->no_gc_sleep_time)
+ *wait = gc_th->max_sleep_time;
+
+ *wait -= gc_th->min_sleep_time;
+ if (*wait <= gc_th->min_sleep_time)
+ *wait = gc_th->min_sleep_time;
+}
+
+static inline bool has_enough_invalid_blocks(struct f2fs_sb_info *sbi)
+{
+ block_t invalid_user_blocks = sbi->user_block_count -
+ written_block_count(sbi);
+ /*
+ * Background GC is triggered with the following conditions.
+ * 1. There are a number of invalid blocks.
+ * 2. There is not enough free space.
+ */
+ if (invalid_user_blocks > limit_invalid_user_blocks(sbi) &&
+ free_user_blocks(sbi) < limit_free_user_blocks(sbi))
+ return true;
+ return false;
+}
+
+static inline int is_idle(struct f2fs_sb_info *sbi)
+{
+ struct block_device *bdev = sbi->sb->s_bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+ struct request_list *rl = &q->root_rl;
+ return !(rl->count[BLK_RW_SYNC]) && !(rl->count[BLK_RW_ASYNC]);
+}