VM overhead

From: Erik Corry (corry@daimi.au.dk)
Date: Thu May 18 2000 - 07:36:59 EST

Next message: Douglas Gilbert: "Re: How can I force a read?"
Previous message: Peter Rival: "Re: Can O_SYNC be implemented by using fsync?"
Next in thread: Rik van Riel: "Re: VM overhead"
Reply: Rik van Riel: "Re: VM overhead"
Maybe reply: Albert D. Cahalan: "Re: VM overhead"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

Hi,

If I mmap 1 Gbyte of VM (anonymously, privately from /dev/zero) but
don't use much of it, how much RAM does the system spend managing
it? Is there a fixed per-page (4k) overhead for the PTEs?

Also, why does top misreport the RSS as 1Gbyte in this case
(kernel 2.2.5-22, procps-2.0.2-2)? Kernel bug?

Do I need more real RAM to fork if I have a large mmap like this?

I am thinking of i386 on 2.2 or 2.4.

-- Erik Corry erik@arbat.com Ceterum censeo, Microsoftem esse delendam!

- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/

Next message: Douglas Gilbert: "Re: How can I force a read?"
Previous message: Peter Rival: "Re: Can O_SYNC be implemented by using fsync?"
Next in thread: Rik van Riel: "Re: VM overhead"
Reply: Rik van Riel: "Re: VM overhead"
Maybe reply: Albert D. Cahalan: "Re: VM overhead"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

This archive was generated by hypermail 2b29 : Tue May 23 2000 - 21:00:15 EST