On Wed, Aug 31 2005, Erik Mouw wrote:
> On Wed, Aug 31, 2005 at 10:07:45AM +0200, Jens Axboe wrote:
> > On Mon, Aug 29 2005, Erik Mouw wrote:
> > > There are four prerequisites for direct IO:
> > > - the file needs to be opened with O_DIRECT
> > > - the buffer needs to be page aligned (hint: use getpagesize() instead
> > > of assuming that a page is 4k
> > > - reads and writes need to happen *in* multiples of the soft block size
> > > - reads and writes need to happen *at* multiples of the soft block size
> >
> > Actually, the buffer only needs to be hard block size aligned, same goes
> > for the chunk size used for reads/writes.
>
> OK, so that's different from 2.4 where reads/writes needed to be soft
> block aligned and buffers page aligned.
Yes, 2.6 has relaxed the restrictions there somewhat.
--
Jens Axboe
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |