Re: [PATCH v1 2/2] f2fs: introduce get_section_mtime
From: liuderong
Date: Thu Sep 12 2024 - 01:16:23 EST
On 2024/9/11 18:22, Chao Yu wrote:
On 2024/9/11 10:40, liuderong@xxxxxxxx wrote:
From: liuderong <liuderong@xxxxxxxx>
When segs_per_sec is larger than 1, section may contain free segments,
mtime should be the mean value of each valid segments,
so introduce get_section_mtime to exclude free segments in a section.
Signed-off-by: liuderong <liuderong@xxxxxxxx>
---
fs/f2fs/f2fs.h | 2 ++
fs/f2fs/gc.c | 15 ++-------------
fs/f2fs/segment.c | 49
++++++++++++++++++++++++++++++++++++++++++++-----
3 files changed, 48 insertions(+), 18 deletions(-)
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 4dcdcdd..d6adf0f 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3762,6 +3762,8 @@ enum rw_hint f2fs_io_type_to_rw_hint(struct
f2fs_sb_info *sbi,
unsigned int f2fs_usable_segs_in_sec(struct f2fs_sb_info *sbi);
unsigned int f2fs_usable_blks_in_seg(struct f2fs_sb_info *sbi,
unsigned int segno);
+unsigned long long get_section_mtime(struct f2fs_sb_info *sbi,
+ unsigned int segno);
#define DEF_FRAGMENT_SIZE 4
#define MIN_FRAGMENT_SIZE 1
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 6299639..03c6117 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -332,20 +332,14 @@ static unsigned int check_bg_victims(struct
f2fs_sb_info *sbi)
static unsigned int get_cb_cost(struct f2fs_sb_info *sbi, unsigned
int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
- unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
- unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
unsigned long long mtime = 0;
unsigned int vblocks;
unsigned char age = 0;
unsigned char u;
- unsigned int i;
unsigned int usable_segs_per_sec =
f2fs_usable_segs_in_sec(sbi);
- for (i = 0; i < usable_segs_per_sec; i++)
- mtime += get_seg_entry(sbi, start + i)->mtime;
+ mtime = get_section_mtime(sbi, segno);
vblocks = get_valid_blocks(sbi, segno, true);
-
- mtime = div_u64(mtime, usable_segs_per_sec);
vblocks = div_u64(vblocks, usable_segs_per_sec);
u = BLKS_TO_SEGS(sbi, vblocks * 100);
@@ -485,10 +479,7 @@ static void add_victim_entry(struct f2fs_sb_info
*sbi,
struct victim_sel_policy *p,
unsigned int segno)
{
struct sit_info *sit_i = SIT_I(sbi);
- unsigned int secno = GET_SEC_FROM_SEG(sbi, segno);
- unsigned int start = GET_SEG_FROM_SEC(sbi, secno);
unsigned long long mtime = 0;
- unsigned int i;
if (unlikely(is_sbi_flag_set(sbi, SBI_CP_DISABLED))) {
if (p->gc_mode == GC_AT &&
@@ -496,9 +487,7 @@ static void add_victim_entry(struct f2fs_sb_info
*sbi,
return;
}
- for (i = 0; i < SEGS_PER_SEC(sbi); i++)
- mtime += get_seg_entry(sbi, start + i)->mtime;
- mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+ mtime = get_section_mtime(sbi, segno);
/* Handle if the system time has changed by the user */
if (mtime < sit_i->min_mtime)
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 6627394..b63f35fa 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -5389,6 +5389,49 @@ unsigned int f2fs_usable_segs_in_sec(struct
f2fs_sb_info *sbi)
return SEGS_PER_SEC(sbi);
}
+unsigned long long get_section_mtime(struct f2fs_sb_info *sbi,
+ unsigned int segno)
+{
+ unsigned int usable_segs_per_sec = f2fs_usable_segs_in_sec(sbi);
+ unsigned int secno = 0, start = 0;
+ struct free_segmap_info *free_i = FREE_I(sbi);
+ unsigned int valid_seg_count = 0;
+ unsigned long long mtime = 0;
+ unsigned int i;
+
+ if (segno == NULL_SEGNO)
+ return 0;
+
+ secno = GET_SEC_FROM_SEG(sbi, segno);
+ start = GET_SEG_FROM_SEC(sbi, secno);
+
+ for (i = 0; i < usable_segs_per_sec; i++) {
+ /* for large section, only check the mtime of valid
segments */
+ if (__is_large_section(sbi)) {
+ spin_lock(&free_i->segmap_lock);
+ if (test_bit(start + i, free_i->free_segmap)) {
+ mtime += get_seg_entry(sbi, start +
i)->mtime;
+ valid_seg_count++;
+ }
+ spin_unlock(&free_i->segmap_lock);
+ } else {
+ mtime += get_seg_entry(sbi, start + i)->mtime;
+ }
+ }
+
+ if (__is_large_section(sbi)) {
+ if (!valid_seg_count)
+ goto out;
+ mtime = div_u64(mtime, valid_seg_count);
+ } else {
+ mtime = div_u64(mtime, usable_segs_per_sec);
+ }
What about:
if (!__is_large_section(sbi))
return get_seg_entry(sbi, start + i)->mtime;
for (i = 0; i < usable_segs_per_sec; i++) {
/* for large section, only check the mtime of valid segments */
...
}
return div_u64(mtime, usable_segs_per_sec);
Thanks,
OK, I will modify the code.
Thanks,
Derong
+
+out:
+ return mtime;
+}
+
/*
* Update min, max modified time for cost-benefit GC algorithm
*/
@@ -5402,13 +5445,9 @@ static void init_min_max_mtime(struct
f2fs_sb_info *sbi)
sit_i->min_mtime = ULLONG_MAX;
for (segno = 0; segno < MAIN_SEGS(sbi); segno +=
SEGS_PER_SEC(sbi)) {
- unsigned int i;
unsigned long long mtime = 0;
- for (i = 0; i < SEGS_PER_SEC(sbi); i++)
- mtime += get_seg_entry(sbi, segno + i)->mtime;
-
- mtime = div_u64(mtime, SEGS_PER_SEC(sbi));
+ mtime = get_section_mtime(sbi, segno);
if (sit_i->min_mtime > mtime)
sit_i->min_mtime = mtime;
--
2.7.4