Re: 2.4 Features

[Peter T. Breuer]

"A month of sundays ago Alexander Viro wrote:"
> > problem with the pagecache and e2compr anyway? Thinking about the
> > implications of an indirection layer, I don't see any. E2compr doesn't
> > use more than a real physical  page of memory at a time?
> 
> Yes, it does. And that's where the pain comes. File is divided into groups
> of pages and every group is compressed separately. Unfortunately, you

Surely this is compression algorithm dependent!  AFAIR all the
compression algorithms avaiolable in e2compr are block compression
algorithms.  Plenty of them can be blocked 4K at a time.  If I remember
even more correctly, that is one of the default choices (and if I
remember even more and more correctly, I usually change it to 32K to get
better ratios, since gzip is fast on decompress, and my cpu is faster on
compress than the disk is on write).

If the above is right, then all one has to do for the moment is disable
e2compr compression blocks of more than PAGESIZE.

Peter