Date: Fri, 06 Jun 2008 18:05:52 -0500 From: Alan Cox <alc@cs.rice.edu> To: Poul-Henning Kamp <phk@phk.freebsd.dk> Cc: Alan Cox <alc@FreeBSD.org>, cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/vm vm_page.c Message-ID: <4849C2D0.9060704@cs.rice.edu> In-Reply-To: <1809.1212779481@critter.freebsd.dk> References: <1809.1212779481@critter.freebsd.dk>
next in thread | previous in thread | raw e-mail | index | archive | help
Poul-Henning Kamp wrote: > In message <200806061838.m56Icu2E074642@repoman.freebsd.org>, Alan Cox writes: > >> alc 2008-06-06 18:38:43 UTC >> >> FreeBSD src repository >> >> Modified files: >> sys/vm vm_page.c >> Log: >> SVN rev 179623 on 2008-06-06 18:38:43Z by alc >> >> Essentially, neither madvise(..., MADV_DONTNEED) nor madvise(..., MADV_FREE) >> work. (Moreover, I don't believe that they have ever worked as intended.) >> > > I remember they did have a measurable but minor impact on performance > in systems which paged a lot, back when they were introduced, sort > of 1995-ish. But with the subsequent plunge in RAM prices they > never saw much use. > > After more thorough digging through CVS history, I now believe that MADV_DONTNEED worked properly between revision 1.70 (May 1996) and 1.76 (June 1996) of vm/vm_object.c. :-) It's more difficult to say for MADV_FREE. It may have been effective until 1999. Alan
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4849C2D0.9060704>