On 2023/1/16 11:08, qixiaoyu1 wrote:
Currently we wrongly calculate the new block age to
old * LAST_AGE_WEIGHT / 100.
Fix it to new * (100 - LAST_AGE_WEIGHT) / 100
+ old * LAST_AGE_WEIGHT / 100.
Signed-off-by: qixiaoyu1 <[email protected]>
Signed-off-by: xiongping1 <[email protected]>
---
Change log v1 -> v2:
- fix udiv
fs/f2fs/extent_cache.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 342af24b2f8c..ad5533f178fd 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -874,11 +874,8 @@ void f2fs_update_read_extent_tree_range_compressed(struct
inode *inode,
static unsigned long long __calculate_block_age(unsigned long long new,
unsigned long long old)
{
- unsigned long long diff;
-
- diff = (new >= old) ? new - (new - old) : new + (old - new);
-
- return div_u64(diff * LAST_AGE_WEIGHT, 100);
+ return div_u64(new, 100) * (100 - LAST_AGE_WEIGHT)
+ + div_u64(old, 100) * LAST_AGE_WEIGHT;
How about updating as below to avoid lossing accuracy if new is less than 100?
return div_u64(new * (100 - LAST_AGE_WEIGHT), 100) +
div_u64(old * LAST_AGE_WEIGHT, 100);
Thanks,
}
/* This returns a new age and allocated blocks in ei */
_______________________________________________
Linux-f2fs-devel mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
