Re: [PATCH] f2fs: enable atgc if atgc_age_threshold from user is less than elapsed_time

From: Chao Yu
Date: Mon Jun 03 2024 - 03:41:16 EST


On 2024/5/20 19:36, Zhiguo Niu wrote:
Now atgc can be enabled based on the following conditions:
-ATGC mount option is set
-elapsed_time is more than atgc_age_threshold already
but these conditions are check when umounted->mounted device again.
If the device has not be umounted->mounted for a long time, atgc can
not work even the above conditions met.

It is better to enable atgc dynamiclly when user change atgc_age_threshold
meanwhile this vale is less than elapsed_time and ATGC mount option is on.

Signed-off-by: Zhiguo Niu <zhiguo.niu@xxxxxxxxxx>
---
fs/f2fs/f2fs.h | 1 +
fs/f2fs/segment.c | 9 ++++-----
fs/f2fs/sysfs.c | 16 ++++++++++++++++
3 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1974b6a..e441d2d 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3694,6 +3694,7 @@ void f2fs_clear_prefree_segments(struct f2fs_sb_info *sbi,
int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi);
void f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi);
void f2fs_restore_inmem_curseg(struct f2fs_sb_info *sbi);
+int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi);
int f2fs_allocate_segment_for_resize(struct f2fs_sb_info *sbi, int type,
unsigned int start, unsigned int end);
int f2fs_allocate_new_section(struct f2fs_sb_info *sbi, int type, bool force);
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 71dc8042..44923d4 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -2931,14 +2931,11 @@ static int get_atssr_segment(struct f2fs_sb_info *sbi, int type,
return ret;
}
-static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
+int f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
{
struct curseg_info *curseg = CURSEG_I(sbi, CURSEG_ALL_DATA_ATGC);
int ret = 0;
- if (!sbi->am.atgc_enabled)
- return 0;
-
f2fs_down_read(&SM_I(sbi)->curseg_lock);
mutex_lock(&curseg->curseg_mutex);
@@ -2955,7 +2952,9 @@ static int __f2fs_init_atgc_curseg(struct f2fs_sb_info *sbi)
}
int f2fs_init_inmem_curseg(struct f2fs_sb_info *sbi)
{
- return __f2fs_init_atgc_curseg(sbi);
+ if (!sbi->am.atgc_enabled)
+ return 0;
+ return f2fs_init_atgc_curseg(sbi);
}
static void __f2fs_save_inmem_curseg(struct f2fs_sb_info *sbi, int type)
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 09d3ecf..72676c5 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -673,6 +673,22 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
return count;
}
+ if (!strcmp(a->attr.name, "atgc_age_threshold")) {
+ if (t < 0)
+ return -EINVAL;
+ sbi->am.age_threshold = t;
+ if (sbi->am.atgc_enabled)
+ return count;
+
+ if (test_opt(sbi, ATGC) &&
+ le64_to_cpu(sbi->ckpt->elapsed_time) >= t) {

Oh, I guess you want to fix this:

static void init_atgc_management(struct f2fs_sb_info *sbi)
{
...
if (test_opt(sbi, ATGC) &&
SIT_I(sbi)->elapsed_time >= DEF_GC_THREAD_AGE_THRESHOLD)
am->atgc_enabled = true;

What about enabling atgc_enabled during checkpoint once elapsed time is
satisfed w/ the condition? I guess this can give another chance whenever
CP is been triggered, and it can avoid the racing condition as well.

Thanks,

+ if (f2fs_init_atgc_curseg(sbi))
+ return -EINVAL;
+ sbi->am.atgc_enabled = true;
+ }
+ return count;
+ }
+
if (!strcmp(a->attr.name, "gc_segment_mode")) {
if (t < MAX_GC_MODE)
sbi->gc_segment_mode = t;