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From: Stefan Hoffmeister <lkml.2001@econos.de>
To: Rik van Riel <riel@conectiva.com.br>
Cc: John Stoffel <stoffel@casc.com>, Jason McMullan <jmcmullan@linuxcare.com>,
        <linux-kernel@vger.kernel.org>
Subject: Re: VM Requirement Document - v0.0
Date: Wed, 27 Jun 2001 00:21:09 +0200
Organization: Econos
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: 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.