On 12/01/2011 04:19 PM, Kyungmin Park wrote: > On 12/1/11, Tao Ma <tm@xxxxxx> wrote: >> Hi Kyungmin, >> On 12/01/2011 03:00 PM, Kyungmin Park wrote: >>> From: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> >>> >>> Now trim information doesn't stored at disk so every boot time. it's >>> cleared. >>> and do the trim all disk groups. >>> But assume that it's already trimmed at previous time so don't need to >>> trim it again. So set the intial state as trimmed. >> sorry, I don't get your meaning here. >> Why can we assume that the group is already trimmed since it isn't >> stored in the disk? > To avoid the first time trim operation. > Every boot time. run the fitrim then it trims all block groups again. > but it's already done at previous time. so don't need to trim it > again. > Doesn't make sense? I think it's not designed behavior. You make the assumption that we run the fitrim every time at boot time. But what if the user don't run it at all? I guess "run fitrim during boot" is your firmware's behaviour and it isn't an assumption for all the other users. Having said that, this flag will be cleared whenever some blocks/clusters are freed. So maybe it doesn't matter for setting this flag during the group initialization. Thanks Tao > > In your patch at http://patchwork.ozlabs.org/patch/102918/ > > with the patch: > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m5.625s > user 0m0.000s > sys 0m1.269s > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m0.002s > user 0m0.000s > sys 0m0.001s > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m0.002s > user 0m0.000s > sys 0m0.001s > > After reboot. it maybe become below > > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m0.002s > user 0m0.000s > sys 0m0.001s > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m0.002s > user 0m0.000s > sys 0m0.001s > [root@boyu-tm linux-2.6]# time ./ftrim /mnt/ext4/a > real 0m0.002s > user 0m0.000s > sys 0m0.001s > > Thank you, > Kyungmin Park >> >> Thanks >> Tao >>> >>> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx> >>> --- >>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c >>> index e2d8be8..97ef342 100644 >>> --- a/fs/ext4/mballoc.c >>> +++ b/fs/ext4/mballoc.c >>> @@ -1098,6 +1098,12 @@ int ext4_mb_init_group(struct super_block *sb, >>> ext4_group_t group) >>> goto err; >>> } >>> mark_page_accessed(page); >>> + >>> + /* >>> + * TRIM information is not stored at disk so set the initial >>> + * state as trimmed. Since previous time it's already trimmed all >>> + */ >>> + EXT4_MB_GRP_SET_TRIMMED(this_grp); >>> err: >>> ext4_mb_put_buddy_page_lock(&e4b); >>> return ret; >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
