On Wed, 2 Feb 2000, Jamie Lokier wrote:
> Chuck Lever wrote:
> > if (mincore(map, readlength, vec))
> > perror("mincore");
> >
> > the vec[] contains a byte for each page you queried. each byte has value
> > "1" if the page is already in memory, otherwise "0".
>
> You do a syscall every time you're going to read part of a file?
you can choose to do this, yes.
> How do you ensure it's still there by the time you actually read it?
the only way to ensure a page is in memory is to use mlock(). mincore()
only provides a hint.
> How do you force the page in when it's not in memory -- spawn
> another thread?
madvise(WILLNEED) is one way to do this asynchronously.
see Vivek Pai's work on the FLASH web server.
- Chuck Lever
-- corporate: <chuckl@netscape.com> personal: <chucklever@netscape.net> or <cel@monkey.org>The Linux Scalability project: http://www.citi.umich.edu/projects/linux-scalability/
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This archive was generated by hypermail 2b29 : Mon Feb 07 2000 - 21:00:08 EST