Messages in this thread | | | Date | Wed, 31 Aug 2005 13:12:48 +0200 | From | Erik Mouw <> | Subject | Re: A problem about DIRECT IO on ext3 |
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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.
Erik
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