Hi Hyunchul, On 2017/12/1 16:28, Hyunchul Lee wrote: > Hi Chao, > > On 11/30/2017 04:06 PM, Chao Yu wrote: >> Hi Hyunchul, >> >> On 2017/11/28 8:23, Hyunchul Lee wrote: >>> From: Hyunchul Lee <cheol.lee@xxxxxxx> >>> >>> This implements which hint is passed down to block layer >>> for datas from the specific segment type. >>> >>> segment type hints >>> ------------ ----- >>> COLD_NODE & COLD_DATA WRITE_LIFE_EXTREME >>> WARM_DATA WRITE_LIFE_NONE >>> HOT_NODE & WARM_NODE WRITE_LIFE_LONG >>> HOT_DATA WRITE_LIFE_MEDIUM >>> META_DATA WRITE_LIFE_SHORT >> >> Just noticed, if our user do not give the hint via ioctl, f2fs can >> provider hint to lower layer according to hot/cold separation ability, >> it will be okay. But once user give his hint which may be more accurate >> than filesystem, hint converted by f2fs may be wrong. >> >> So what do you think of adding an option to control whether filesystem >> can convert hint user given? >> > > I think it is okay for LIFE_SHORT and LIFE_EXTREME. because they are > converted to different hints. What I mean is introducing a mount option, e.g. fs_iohint, a) w/o fs_iohint, propagate file/inode io_hint to low layer. b) w/ fs_iohint, ignore file/inode io_hint, use io_hint which is generated with filesystem's private rule. Thanks, > > file hint segment type io hint > --------- ------------ ------- > LIFE_SHORT HOT_DATA LIFE_MEDIUM > LIFE_MEDIUM WARM_DATA LIFE_NONE > LIFE_LONG WARM_DATA LIFE_NONE > LIFE_EXTREME COLD_DATA LIFE_EXTREME > > the problem is that LIFE_MEDIUM and LIFE_LONG are converted to > the same hint, LIFE_NONE. I am not sure that the seperation between > LIFE_MEDIUM and LIFE_LONG is really needed. Because I guess that the > difference between them is a little ambigous for users, and if WARM_DATA > segment has two different hints, it can makes GC non-efficient. > > I wonder your thought about this. > > Thanks. > >> Thanks, >> >> > > ------------------------------------------------------------------------------ > Check out the vibrant tech community on one of the world's most > engaging tech sites, Slashdot.org! http://sdm.link/slashdot > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel >
