Re: [PATCH v2 5/5] f2fs: support age threshold based garbage collection

From: Chao Yu
Date: Mon Aug 31 2020 - 23:25:10 EST


Jaegeuk, I missed one ')' in this diff, thanks for fixing in upstream.

Thanks,

On 2020/9/1 2:01, Jaegeuk Kim wrote:
Hi Chao,

Applied. Thanks.

On 08/31, Chao Yu wrote:
Hi Jaegeuk,

I've changed code a bit to fix some bugs, including:
- gc_idle = 3 (GC_IDLE_AT) description
- disallow set gc_idle to 3 if atgc is off
- keep compatibility with checkpoint disabling

Could you please check and merge below diff?

From: Chao Yu <yuchao0@xxxxxxxxxx>

Signed-off-by: Chao Yu <yuchao0@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 3 ++-
fs/f2fs/gc.c | 12 +++++++++++-
fs/f2fs/sysfs.c | 11 ++++++++---
3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 7f730c4c8df2..834d0becae6d 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -22,7 +22,8 @@ Contact: "Namjae Jeon" <namjae.jeon@xxxxxxxxxxx>
Description: Controls the victim selection policy for garbage collection.
Setting gc_idle = 0(default) will disable this option. Setting
gc_idle = 1 will select the Cost Benefit approach & setting
- gc_idle = 2 will select the greedy approach.
+ gc_idle = 2 will select the greedy approach & setting
+ gc_idle = 3 will select the age-threshold based approach.

What: /sys/fs/f2fs/<disk>/reclaim_segments
Date: October 2013
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6413886e52d4..3c0edb8b4cc5 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -388,6 +388,16 @@ static void add_victim_entry(struct f2fs_sb_info *sbi,
unsigned long long mtime = 0;
unsigned int i;

+ if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED)) {
+ if (p->gc_mode == GC_AT &&
+ get_valid_blocks(sbi, segno, true) == 0)
+ return;
+
+ if (p->alloc_mode == AT_SSR &&
+ get_seg_entry(sbi, segno)->ckpt_valid_blocks == 0)
+ return;
+ }
+
for (i = 0; i < sbi->segs_per_sec; i++)
mtime += get_seg_entry(sbi, start + i)->mtime;
mtime = div_u64(mtime, sbi->segs_per_sec);
@@ -721,7 +731,7 @@ static int get_victim_by_default(struct f2fs_sb_info *sbi,
/* Don't touch checkpointed data */
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED) &&
get_ckpt_valid_blocks(sbi, segno) &&
- p.alloc_mode != SSR))
+ p.alloc_mode == LFS))
goto next;
if (gc_type == BG_GC && test_bit(secno, dirty_i->victim_secmap))
goto next;
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 88ed9969cc86..bacfa9c35e6b 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -375,12 +375,17 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
return count;
}
if (!strcmp(a->attr.name, "gc_idle")) {
- if (t == GC_IDLE_CB)
+ if (t == GC_IDLE_CB) {
sbi->gc_mode = GC_IDLE_CB;
- else if (t == GC_IDLE_GREEDY)
+ } else if (t == GC_IDLE_GREEDY) {
sbi->gc_mode = GC_IDLE_GREEDY;
- else
+ } else if (t == GC_IDLE_AT) {
+ if (!sbi->am.atgc_enabled)
+ return -EINVAL;
+ sbi->gc_mode = GC_AT;
+ } else {
sbi->gc_mode = GC_NORMAL;
+ }
return count;
}

--
2.26.2

.