> 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
>
There is a BSD-originated convention for this - madvise().
If you look in the Linux VM code there is a bit of explicit code for
different madvise access patterns, but I'm not sure if it's 100% supported.
Drop-behind would be really, really nice to have for my multimedia
applications. I routinely deal with very large video files (several times
larger than my RAM). When I sequentially read though such files a bit at a
time, I do NOT want the old pages sitting there in RAM while all of my other
running programs are rudely paged out...
(hrm, maybe I could hack up my own manual read-ahead/drop-behind with mmap()
and memory locking...)
Regards,
Dan
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This archive was generated by hypermail 2b29 : Sat Jun 30 2001 - 21:00:15 EST