Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 9 Apr 2003 14:16:08 +0200 | From | Rob van Nieuwkerk <> | Subject | O_DIRECT alignment requirements ? |
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Hi all,
I plan to use O_DIRECT in my application (on a partition, no fs). It is hard to find info on the exact requirements on the mandatory alignments of buffer, offset, transfer size: it's easy to find many contradicting documents. And checking the kernel source itself isn't trivial.
lseek(int fildes, off_t offset, int whence); read(int fd, void *buf, size_t count);
My current assumption is this:
- offset must be block_aligned (multiple of 512) - buf must be page_aligned (4096 on IA32) - count must be "block_aligned" (multiple of 512)
Is this correct ?
r.
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