On Wed, 12 Feb 2014 09:58:31 +0900 (JST), Ryusuke Konishi wrote: > On Tue, 11 Feb 2014 20:58:45 +0100, Andreas Rohner wrote: >> On 2014-02-11 19:11, Ryusuke Konishi wrote: >>> On Tue, 11 Feb 2014 15:07:48 +0100, Andreas Rohner wrote: >>> Honestly, I'm still hesitative about the full scan approach since the >>> mount time depends on the device size and the medium type. >> >> I wouldn't recommend it as the default recovery option. The user has to >> make a decision if it is right for his or her device and activate it. >> But until now it is just a stupid experiment. It would only be useful in >> certain corner cases anyway. Thanks for reviewing it! >> >>> If we define some window size based on the performance of the device >>> (which would be measured and written in super block with mkfs or >>> nilfs-tune), and can limit the range of scan, things may become more >>> manageable. >> >> That would certainly be possible. The window would start at s_last_pseg >> and end at (s_last_pseg + window size). We could then simply force a >> super block write as soon as the first segment is allocated outside of >> the window. This could still significantly reduce the number of writes >> to the super block. >> >> Thanks for your review, > > You're welcome, thank you, too. > > By the way, we have another todo for flash devices. It is FITRIM > ioctl support. FITRIM is an API to issue TRIM/DISCARD requests > (through blkdev_issue_flash function) to a portion of underlying Oops, I made a mistake. it was blkdev_issue_discard(). Ryusuke Konishi > device to allow batch DISCARD by userland tools. It helps GC > optimization of underlying flash device or thinprovisioning feature of > block storage. NILFS is suit for implementing this feature since free > space is managed in segment unit and sufile is available, but was long > time left. > > If you have an interest, please take a look at it, too. > > Thanks, > Ryusuke Konishi > -- > To unsubscribe from this list: send the line "unsubscribe linux-nilfs" 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-nilfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
