Christoph Hellwig <hch@xxxxxx> writes: > On Thu, Nov 19, 2009 at 03:38:04AM +0900, OGAWA Hirofumi wrote: >> Christoph Hellwig <hch@xxxxxx> writes: >> >> > Currently shipping discard capable SSDs and arrays have rather sub-optimal >> > implementations of the command and can the use of it can cause massive >> > slowdowns. Make issueing these commands option as it's already in btrfs >> > and gfs2. >> >> Thanks. Looks good to me, I'll apply as is. >> >> BTW, what value is default for those users? And from users of some >> filesystems, it might be better to do in lower layer or VFS? > > The situation is the following: > > As of 2.6.32-rc7: > > - btrfs needs the discard option to enable trim, it's off by default > - gfs2 needs the discard option to enable trim, it's off by default > - ext4 does discard by default, no option to disable > - fat does discard by default, no option to disable > - the swap code does discard by default, no option to disable Thanks. From it, I'll use the disable by default, if you don't have problem. > Eric has a patch for ext4 to implement the btrfs/gfs2 semantics, and > this is the one for fat. A discussion is ongoing about swap. > > I don't think moving block specific options is a good idea to do in the > VFS. The other option would be to disable it in the block layer, but > that's not alwas intuitive. Yes. But, on the other view, it is the capability of block device (trim like stuff is useful on it, or not. Also it would be able to used for blacklist from driver). Well, actually, I'm caring the difference of default for those options can confuse a bit for users. Thanks. -- OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
