On 01/22/2012 05:49 PM, James Bottomley wrote: > > But this topic then becomes adding alignment for non block backed > filesystems? I take it you're thinking NFS rather than MTD or MMC? > Sorry to differ. But no this is for most making the IO aligned in the first place. Block-dev or not. Today VFS has no notion of alignment and IO is submitted as is with out any alignment considerations. > For multiple devices, you do a simple cascade ... a bit like dm does > today ... but unless all the devices are aligned to optimal I/O it never > really works (and it's not necessarily worth solving ... the idea that > if you want performance from an array of devices, you match > characteristics isn't a hugely hard one to get the industry to swallow). > No I'm talking about raid configurations like object raid in exofs/NFS or raid0/5 in BTRFS and ZFS and such, where there are other larger alignment structures to consider. Also for large-blocks filesystems/devices who would like IO aligned on bigger than a page sizes. Thanks Boaz -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>