Hi,
On Thu, 24 Feb 2000 03:35:02 +0100, Jamie Lokier
<lk@tantalophile.demon.co.uk> said:
> I don't think MADV_DONTNEED actually drops privately modified data does
> it?
Yes, it does. From the DU man pages:
MADV_DONTNEED
Do not need these pages
The system will free any whole pages in the specified
region. All modifications will be lost and any swapped
out pages will be discarded. Subsequent access to the
region will result in a zero-fill-on-demand fault as
though it is being accessed for the first time.
Reserved swap space is not affected by this call.
Regarding the other half of the problem --- zeroing out a portion of a
file without further IO --- the splice code I hope to have using kiobufs
in 2.5 will allow this to be done very easily. You'll be able to take a
region of /dev/zero and splice it into your open file with zero-copy.
--Stephen
-
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/
This archive was generated by hypermail 2b29 : Tue Feb 29 2000 - 21:00:09 EST