On Thu, 2018-10-18 at 07:03 -0700, Matthew Wilcox wrote:
> On Thu, Oct 18, 2018 at 09:18:12PM +0800, Ming Lei wrote:
> > Filesystems may allocate io buffer from slab, and use this buffer to
> > submit bio. This way may break storage drivers if they have special
> > requirement on DMA alignment.
>
On Thu, Oct 18, 2018 at 08:06:05AM -0700, Matthew Wilcox wrote:
> Can you name one that does require 512-byte alignment, preferably still
> in use? Or even >4-byte alignment. I just checked AHCI and that requires
> only 2-byte alignment.
Xen-blkfront, rsxx, various SD/MMC card readers for
On Thu, Oct 18, 2018 at 04:05:51PM +0200, Christoph Hellwig wrote:
> On Thu, Oct 18, 2018 at 07:03:42AM -0700, Matthew Wilcox wrote:
> > Before we go down this road, could we have a discussion about what
> > hardware actually requires this? Storage has this weird assumption that
> > I/Os must be
On Thu, Oct 18, 2018 at 07:03:42AM -0700, Matthew Wilcox wrote:
> Before we go down this road, could we have a discussion about what
> hardware actually requires this? Storage has this weird assumption that
> I/Os must be at least 512 byte aligned in memory, and I don't know where
> this idea
On Thu, Oct 18, 2018 at 09:18:12PM +0800, Ming Lei wrote:
> Hi,
>
> Filesystems may allocate io buffer from slab, and use this buffer to
> submit bio. This way may break storage drivers if they have special
> requirement on DMA alignment.
Before we go down this road, could we have a discussion
