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authorChao Yu <chao2.yu@samsung.com>2016-01-23 16:23:55 +0800
committerJaegeuk Kim <jaegeuk@kernel.org>2016-02-22 16:07:23 -0800
commit718e53fa633f84d09acb4b76f1ad572ccbf75a12 (patch)
tree8af154aa74c51905cc7f5d5db193902346868963 /fs/f2fs
parente3ef18762f5757d3fb86f75ca59315db6d17d719 (diff)
downloadlinux-718e53fa633f84d09acb4b76f1ad572ccbf75a12.tar.bz2
f2fs: enhance foreground GC
If we configure section consist of multiple segments, foreground GC will do the garbage collection with following approach: for each segment in victim section blk_start_plug for each valid block in segment write out by OPU method submit bio cache <--- blk_finish_plug <--- There are two issue: 1) for most of the time, 'submit bio cache' will break the merging in current bio buffer from writes of next segments, making a smaller bio submitting. 2) block plug only cover IO submitting in one segment, which reduce opportunity of merging IOs in plug with multiple segments. So refactor the code as below structure to strive for biggest opportunity of merging IOs: blk_start_plug for each segment in victim section for each valid block in segment write out by OPU method submit bio cache blk_finish_plug Test method: 1. mkfs.f2fs -s 8 /dev/sdX 2. touch 32 files 3. write 2M data into each file 4. punch 1.5M data from offset 0 for each file 5. trigger foreground gc through ioctl Before patch, there are totoally 40 bios submitted. f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65536, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65776, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66016, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66256, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66496, size = 32768 ----repeat for 8 times After patch, there are totally 35 bios submitted. f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65536, size = 122880 ----repeat 34 times f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 73696, size = 16384 Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs')
-rw-r--r--fs/f2fs/gc.c143
1 files changed, 72 insertions, 71 deletions
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 4a704a16bf17..c1f363d2b17c 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -399,7 +399,7 @@ static int check_valid_map(struct f2fs_sb_info *sbi,
* On validity, copy that node with cold status, otherwise (invalid node)
* ignore that.
*/
-static int gc_node_segment(struct f2fs_sb_info *sbi,
+static void gc_node_segment(struct f2fs_sb_info *sbi,
struct f2fs_summary *sum, unsigned int segno, int gc_type)
{
bool initial = true;
@@ -419,7 +419,7 @@ next_step:
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
- return 0;
+ return;
if (check_valid_map(sbi, segno, off) == 0)
continue;
@@ -460,20 +460,6 @@ next_step:
initial = false;
goto next_step;
}
-
- if (gc_type == FG_GC) {
- struct writeback_control wbc = {
- .sync_mode = WB_SYNC_ALL,
- .nr_to_write = LONG_MAX,
- .for_reclaim = 0,
- };
- sync_node_pages(sbi, 0, &wbc);
-
- /* return 1 only if FG_GC succefully reclaimed one */
- if (get_valid_blocks(sbi, segno, 1) == 0)
- return 1;
- }
- return 0;
}
/*
@@ -663,7 +649,7 @@ out:
* If the parent node is not valid or the data block address is different,
* the victim data block is ignored.
*/
-static int gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
+static void gc_data_segment(struct f2fs_sb_info *sbi, struct f2fs_summary *sum,
struct gc_inode_list *gc_list, unsigned int segno, int gc_type)
{
struct super_block *sb = sbi->sb;
@@ -686,7 +672,7 @@ next_step:
/* stop BG_GC if there is not enough free sections. */
if (gc_type == BG_GC && has_not_enough_free_secs(sbi, 0))
- return 0;
+ return;
if (check_valid_map(sbi, segno, off) == 0)
continue;
@@ -747,15 +733,6 @@ next_step:
if (++phase < 4)
goto next_step;
-
- if (gc_type == FG_GC) {
- f2fs_submit_merged_bio(sbi, DATA, WRITE);
-
- /* return 1 only if FG_GC succefully reclaimed one */
- if (get_valid_blocks(sbi, segno, 1) == 0)
- return 1;
- }
- return 0;
}
static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
@@ -771,53 +748,90 @@ static int __get_victim(struct f2fs_sb_info *sbi, unsigned int *victim,
return ret;
}
-static int do_garbage_collect(struct f2fs_sb_info *sbi, unsigned int segno,
+static int do_garbage_collect(struct f2fs_sb_info *sbi,
+ unsigned int start_segno,
struct gc_inode_list *gc_list, int gc_type)
{
struct page *sum_page;
struct f2fs_summary_block *sum;
struct blk_plug plug;
- int nfree = 0;
+ unsigned int segno = start_segno;
+ unsigned int end_segno = start_segno + sbi->segs_per_sec;
+ int seg_freed = 0;
+ unsigned char type = IS_DATASEG(get_seg_entry(sbi, segno)->type) ?
+ SUM_TYPE_DATA : SUM_TYPE_NODE;
- /* read segment summary of victim */
- sum_page = get_sum_page(sbi, segno);
+ /* readahead multi ssa blocks those have contiguous address */
+ if (sbi->segs_per_sec > 1)
+ ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno),
+ sbi->segs_per_sec, META_SSA, true);
+
+ /* reference all summary page */
+ while (segno < end_segno) {
+ sum_page = get_sum_page(sbi, segno++);
+ unlock_page(sum_page);
+ }
blk_start_plug(&plug);
- sum = page_address(sum_page);
+ for (segno = start_segno; segno < end_segno; segno++) {
+ /* find segment summary of victim */
+ sum_page = find_get_page(META_MAPPING(sbi),
+ GET_SUM_BLOCK(sbi, segno));
+ f2fs_bug_on(sbi, !PageUptodate(sum_page));
+ f2fs_put_page(sum_page, 0);
- /*
- * this is to avoid deadlock:
- * - lock_page(sum_page) - f2fs_replace_block
- * - check_valid_map() - mutex_lock(sentry_lock)
- * - mutex_lock(sentry_lock) - change_curseg()
- * - lock_page(sum_page)
- */
- unlock_page(sum_page);
-
- switch (GET_SUM_TYPE((&sum->footer))) {
- case SUM_TYPE_NODE:
- nfree = gc_node_segment(sbi, sum->entries, segno, gc_type);
- break;
- case SUM_TYPE_DATA:
- nfree = gc_data_segment(sbi, sum->entries, gc_list,
- segno, gc_type);
- break;
+ sum = page_address(sum_page);
+ f2fs_bug_on(sbi, type != GET_SUM_TYPE((&sum->footer)));
+
+ /*
+ * this is to avoid deadlock:
+ * - lock_page(sum_page) - f2fs_replace_block
+ * - check_valid_map() - mutex_lock(sentry_lock)
+ * - mutex_lock(sentry_lock) - change_curseg()
+ * - lock_page(sum_page)
+ */
+
+ if (type == SUM_TYPE_NODE)
+ gc_node_segment(sbi, sum->entries, segno, gc_type);
+ else
+ gc_data_segment(sbi, sum->entries, gc_list, segno,
+ gc_type);
+
+ stat_inc_seg_count(sbi, type, gc_type);
+ stat_inc_call_count(sbi->stat_info);
+
+ f2fs_put_page(sum_page, 0);
+ }
+
+ if (gc_type == FG_GC) {
+ if (type == SUM_TYPE_NODE) {
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = LONG_MAX,
+ .for_reclaim = 0,
+ };
+ sync_node_pages(sbi, 0, &wbc);
+ } else {
+ f2fs_submit_merged_bio(sbi, DATA, WRITE);
+ }
}
- blk_finish_plug(&plug);
- stat_inc_seg_count(sbi, GET_SUM_TYPE((&sum->footer)), gc_type);
- stat_inc_call_count(sbi->stat_info);
+ blk_finish_plug(&plug);
- f2fs_put_page(sum_page, 0);
- return nfree;
+ if (gc_type == FG_GC) {
+ while (start_segno < end_segno)
+ if (get_valid_blocks(sbi, start_segno++, 1) == 0)
+ seg_freed++;
+ }
+ return seg_freed;
}
int f2fs_gc(struct f2fs_sb_info *sbi, bool sync)
{
- unsigned int segno, i;
+ unsigned int segno;
int gc_type = sync ? FG_GC : BG_GC;
- int sec_freed = 0;
+ int sec_freed = 0, seg_freed;
int ret = -EINVAL;
struct cp_control cpc;
struct gc_inode_list gc_list = {
@@ -853,22 +867,9 @@ gc_more:
goto stop;
ret = 0;
- /* readahead multi ssa blocks those have contiguous address */
- if (sbi->segs_per_sec > 1)
- ra_meta_pages(sbi, GET_SUM_BLOCK(sbi, segno), sbi->segs_per_sec,
- META_SSA, true);
-
- for (i = 0; i < sbi->segs_per_sec; i++) {
- /*
- * for FG_GC case, halt gcing left segments once failed one
- * of segments in selected section to avoid long latency.
- */
- if (!do_garbage_collect(sbi, segno + i, &gc_list, gc_type) &&
- gc_type == FG_GC)
- break;
- }
+ seg_freed = do_garbage_collect(sbi, segno, &gc_list, gc_type);
- if (i == sbi->segs_per_sec && gc_type == FG_GC)
+ if (gc_type == FG_GC && seg_freed == sbi->segs_per_sec)
sec_freed++;
if (gc_type == FG_GC)