Re: page->offset

["Stephen C. Tweedie" <sct@redhat.com>]

Hi,

On Wed, Apr 12, 2000 at 06:34:21PM +0530, pnilesh@in.ibm.com wrote:
> 
> If a file is opened and from an offset which is not page aligned say from
> offset 10.
> When we read this file into the memory page ,where the first byte will be
> loaded into the memory ?
> In 2.2 the first byte of the page will be the 10th byte of the file.
> In 2.3 the first byte will be first byte in the file and 10th byte is the
> 10th in the file.

No.  The cache will always be page aligned in both 2.2 and 2.3 for
all user IO and for all mmap()ed files.  The _only_ case where we
allow non-aligned mappings is when the execve() syscall is executed
on a QMAGIC binary, in which case 2.2 will allow the mapping and
will page the binary in at unaligned offsets when page faults occur.

--Stephen
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