Re: VM Requirement Document - v0.0

Stefan Hoffmeister (lkml.2001@econos.de)
Wed, 27 Jun 2001 00:21:09 +0200


: On Tue, 26 Jun 2001 18:42:56 -0300 (BRST), Rik van Riel wrote:

>On Tue, 26 Jun 2001, John Stoffel wrote:
>
>> Or that we're doing big sequential reads of file(s) which are
>> larger than memory, in which case expanding the cache size buys
>> us nothing, and can actually hurt us alot.
>
>That's a big "OR". I think we should have an algorithm to
>see which of these two is the case, otherwise we're just
>making the wrong decision half of the time.

Windows NT/2000 has flags that can be for each CreateFile operation
("open" in Unix terms), for instance

FILE_ATTRIBUTE_TEMPORARY

FILE_FLAG_WRITE_THROUGH
FILE_FLAG_NO_BUFFERING
FILE_FLAG_RANDOM_ACCESS
FILE_FLAG_SEQUENTIAL_SCAN

If Linux does not have mechanism that would allow the signalling of
specific use case, it might be helpful to implement such a hinting system?

Disclaimer: I am clueless about what the kernel provides at this time.
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