From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 16 May 2001 10:14:15 -0700 (PDT) From: Matt Dillon Message-Id: <200105161714.f4GHEFs72217@earth.backplane.com> Subject: Re: RE: on load control / process swapping References: <5FE9B713CCCDD311A03400508B8B30130828EDA8@bdr-xcln.corp.matchlogic.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Charles Randall Cc: Roger Larsson , Rik van Riel , arch@FreeBSD.ORG, linux-mm@kvack.org, sfkaplan@cs.amherst.edu List-ID: We've talked about implementing O_DIRECT. I think it's a good idea. In regards to the particular case of scanning a huge multi-gigabyte file, FreeBSD has a sequential detection heuristic which does a pretty good job preventing cache blow-aways by depressing the priority of the data as it is read or written. FreeBSD will still try to cache a good chunk, but it won't sacrifice all available memory. If you access the data via the VM system, through mmap, you get even more control through the madvise() syscall. -Matt -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux.eu.org/Linux-MM/