Messages in this thread | | | Subject | Re: [PATCH] f2fs: set file as cold when file defragmentation | From | Chao Yu <> | Date | Tue, 11 May 2021 14:07:29 +0800 |
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On 2021/5/11 13:09, Jaegeuk Kim wrote: > On 05/11, Chao Yu wrote: >> On 2021/5/10 22:47, Jaegeuk Kim wrote: >>> On 05/06, Chao Yu wrote: >>>> On 2021/5/6 12:46, Jaegeuk Kim wrote: >>>>> On 05/06, Chao Yu wrote: >>>>>> On 2021/4/29 14:20, Daejun Park wrote: >>>>>>> In file defragmentation by ioctl, all data blocks in the file are >>>>>>> re-written out-of-place. File defragmentation implies user will not update >>>>>>> and mostly read the file. So before the defragmentation, we set file >>>>>>> temperature as cold for better block allocation. >>>>>> >>>>>> I don't think all fragmented files are cold, e.g. db file. >>>>> >>>>> I have a bit different opinion. I think one example would be users want to >>>>> defragment a file, when the they want to get higher read bandwidth for >>>> >>>> Multimedia file was already defined as cold file now via default extension >>>> list? >>> >>> I just gave an example. And default is default. >>> >>>> >>>>> usually multimedia files. That's likely to be cold files. Moreover, I don't >>>>> think they want to defragment db files which will be fragmented soon? >>>> >>>> I guess like db files have less update but more access? >>> >>> I think both, and we set it as hot. >> >> Then hot and cold bit will set to the same db file after defragmentation? > > Do you set cold bit to db files? I mean, generally db is not cold, but hot.
I never set cold bit to db files, I mean if we defragment db file which has less update and more access, db file may have bot hot and cold bit.
To Daejun, may I ask that is Samsung planning to use this defragment ioctl in products? what's the user scenario?
Thanks,
> >> >> Thanks, >> >>> >>>> >>>> Thanks, >>>> >>>>> >>>>>> >>>>>> We have separated interface (via f2fs_xattr_advise_handler, e.g. setfattr -n >>>>>> "system.advise" -v value) to indicate this file is a hot/cold file, so my >>>>>> suggestion is after file defragmentation, if you think this file is cold, and >>>>>> use setxattr() to set it as cold. >>>>>> >>>>>> Thanks, >>>>>> >>>>>>> >>>>>>> Signed-off-by: Daejun Park <daejun7.park@samsung.com> >>>>>>> --- >>>>>>> fs/f2fs/file.c | 3 +++ >>>>>>> 1 file changed, 3 insertions(+) >>>>>>> >>>>>>> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >>>>>>> index d697c8900fa7..dcac965a05fe 100644 >>>>>>> --- a/fs/f2fs/file.c >>>>>>> +++ b/fs/f2fs/file.c >>>>>>> @@ -2669,6 +2669,9 @@ static int f2fs_defragment_range(struct f2fs_sb_info *sbi, >>>>>>> map.m_len = pg_end - pg_start; >>>>>>> total = 0; >>>>>>> + if (!file_is_cold(inode)) >>>>>>> + file_set_cold(inode); >>>>>>> + >>>>>>> while (map.m_lblk < pg_end) { >>>>>>> pgoff_t idx; >>>>>>> int cnt = 0; >>>>>>> >>>>> . >>>>> >>> . >>> > . >
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