Re: ~500 megs cached yet 2.6.5 goes into swap hell

Jeff Garzik
2004-04-30T07:52:50Z

Andrew Morton wrote:
> Andy Isaacson <adi@hexapodia.org> wrote:
>
>> But in a related case, I have a background daemon that does a lot of IO
>> (mostly sequential, one page at a time read/modify/write of a multi-GB
>> file) to a filesystem on a separate spindle from my main filesystems.
>> I'd like to use a similar mechanism to say "don't let this program eat
>> my pagecache" that will let the daemon crunch away without severely
>> impacting my desktop work.
>
>
> fadvise(POSIX_FADV_DONTNEED) is ideal for this. Run it once per megabyte
> or so.

Sweet. I'm so happy you added posix_fadvise (way back when), and even
happier to hear this.

Does our fadvise support len==0 ("I mean the whole file")? That's
defined in POSIX, and would allow a compliant app to simply
POSIX_FADV_DONTNEED once at the beginning.

Jeff