1 files changed, 117 insertions, 0 deletions
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
new file mode 100644
index 000000000000..cf42a554ca0a
--- /dev/null
+++ b/fs/f2fs/gc.h
@@ -0,0 +1,117 @@
+/**
+ * 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_NAME	"f2fs_gc_task"
+#define GC_THREAD_MIN_WB_PAGES		1	/*
+						 * a threshold to determine
+						 * whether IO subsystem is idle
+						 * or not
+						 */
+#define GC_THREAD_MIN_SLEEP_TIME	10000 /* milliseconds */
+#define GC_THREAD_MAX_SLEEP_TIME	30000
+#define GC_THREAD_NOGC_SLEEP_TIME	10000
+#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 MAX_VICTIM_SEARCH	20
+
+enum {
+	GC_NONE = 0,
+	GC_ERROR,
+	GC_OK,
+	GC_NEXT,
+	GC_BLOCKED,
+	GC_DONE,
+};
+
+struct f2fs_gc_kthread {
+	struct task_struct *f2fs_gc_task;
+	wait_queue_head_t gc_wait_queue_head;
+};
+
+struct inode_entry {
+	struct list_head list;
+	struct inode *inode;
+};
+
+/**
+ * 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 long increase_sleep_time(long wait)
+{
+	wait += GC_THREAD_MIN_SLEEP_TIME;
+	if (wait > GC_THREAD_MAX_SLEEP_TIME)
+		wait = GC_THREAD_MAX_SLEEP_TIME;
+	return wait;
+}
+
+static inline long decrease_sleep_time(long wait)
+{
+	wait -= GC_THREAD_MIN_SLEEP_TIME;
+	if (wait <= GC_THREAD_MIN_SLEEP_TIME)
+		wait = GC_THREAD_MIN_SLEEP_TIME;
+	return wait;
+}
+
+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 condition.
+	 * 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]);
+}
+
+static inline bool should_do_checkpoint(struct f2fs_sb_info *sbi)
+{
+	unsigned int pages_per_sec = sbi->segs_per_sec *
+					(1 << sbi->log_blocks_per_seg);
+	int node_secs = ((get_pages(sbi, F2FS_DIRTY_NODES) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+	int dent_secs = ((get_pages(sbi, F2FS_DIRTY_DENTS) + pages_per_sec - 1)
+			>> sbi->log_blocks_per_seg) / sbi->segs_per_sec;
+	return free_sections(sbi) <= (node_secs + 2 * dent_secs + 2);
+}