> -----Original Message----- > From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx] > Sent: Thursday, December 24, 2015 4:11 AM > Subject: Re: A blocksize problem about dax and ext4 > > On Thu, Dec 24, 2015 at 02:47:07AM +0000, Elliott, Robert (Persistent > Memory) wrote: > > > Did you mean that I should make the blocksize bigger until the mount > > > command tell me that dax is enabled? > > > > To really use DAX, the filesystem block size must match the > > system CPU's page size, which is probably 4096 bytes. > > No, it doesn't. File you use for DAX must be aligne at page size > granularity. For XFS you could do this with the per-inode extent > size hint for example even if the overall block size is smaller. I think that's a future goal. Currently, the checks are like this: if (sb->s_blocksize != PAGE_SIZE) { xfs_alert(mp, "Filesystem block size invalid for DAX Turning DAX off."); -- 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
