Re: PAGE_SIZE Availability Inconsistency

David Miller wrote:
> From: "H. Peter Anvin" <hpazytor.com>
> Date: Thu, 08 Mar 2007 20:18:28 -0800
> 
>> Anton Blanchard wrote:
>>> The other option is to create a v3 swap format
that doesnt use any
>>> PAGE_SIZE parameters.
>> The best thing to do would be to look for the magic
both at PAGE_SIZE 
>> (for compatibility) and MIN_PAGE_SIZE (for
sanity.)
> 
> That might work, but a large part of me says to go for
v3
> and do it cleanly.

The advantage would be that it wouldn't require a v3 for
platforms for 
which MIN_PAGE_SIZE == PAGE_SIZE, which accounts for a very
large 
percentage of systems.

You still have to look for the darn magic in two places, so
there is no 
reason for it to be different.

	-hpa

From: "H. Peter Anvin" <hpazytor.com>
Date: Thu, 08 Mar 2007 20:31:05 -0800

> The advantage would be that it wouldn't require a v3
for platforms for 
> which MIN_PAGE_SIZE == PAGE_SIZE, which accounts for a
very large 
> percentage of systems.
> 
> You still have to look for the darn magic in two
places, so there is no 
> reason for it to be different.

Good point.

Hi,

> The advantage would be that it wouldn't require a v3
for platforms for 
> which MIN_PAGE_SIZE == PAGE_SIZE, which accounts for a
very large 
> percentage of systems.
> 
> You still have to look for the darn magic in two
places, so there is no 
> reason for it to be different.

The problem is if you can hit in two places then what
PAGE_SIZE should
you use to size the contents of the swap header while
remaining backward
compatible.

Im leaning towards Dave suggestion of creating a clean v3
swap header.

Anton