Re: fs block size and PAGE_CACHE_SIZE

Phillip Lougher
2003-05-07T00:45:01Z

Bryan Henderson wrote:

>
>>how could I efficient populate one 16k block to page cache(4 pages) at one
>>
>readpage() op?
>
>Why would you want to? If someone wants to access those other 3 pages,
>they'll have page faults of their own.
>
In an uncompressed filesystem this is not a problem because the
additional page faults (read_page), will read the pages out of the block
cache. However, for a compressed filesystem, the 16K block would
have to be (re-)decompressed evey time, because the block is compressed
in the block cache. It is much more efficient to push the extra
decompressed pages into the page cache.

Regards

Phillip Lougher