From owner-freebsd-hackers Tue Apr 4 16:40:44 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id QAA26573 for hackers-outgoing; Tue, 4 Apr 1995 16:40:44 -0700 Received: from Root.COM (implode.Root.COM [198.145.90.1]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id QAA26566 for ; Tue, 4 Apr 1995 16:40:40 -0700 Received: from corbin.Root.COM (corbin.Root.COM [198.145.90.18]) by Root.COM (8.6.8/8.6.5) with ESMTP id QAA07154; Tue, 4 Apr 1995 16:40:07 -0700 Received: from localhost (localhost [127.0.0.1]) by corbin.Root.COM (8.6.11/8.6.5) with SMTP id QAA00208; Tue, 4 Apr 1995 16:40:07 -0700 Message-Id: <199504042340.QAA00208@corbin.Root.COM> X-Authentication-Warning: corbin.Root.COM: Host localhost didn't use HELO protocol To: Luigi Rizzo cc: hackers@FreeBSD.org Subject: Re: swap always use at least 64KB ? In-reply-to: Your message of "Tue, 04 Apr 95 19:23:14 +0200." <199504041723.TAA00153@labinfo.iet.unipi.it> From: David Greenman Reply-To: davidg@Root.COM Date: Tue, 04 Apr 1995 16:40:07 -0700 Sender: hackers-owner@FreeBSD.org Precedence: bulk >I noticed this on snap950210, but didn't pay too much attention to it. >Now (snap950322) I decided to enable swap to a file, created /dev/vn0*, >did > > vnconfig -e /dev/vn0b myfile swap > >and, surprise surprise, swapinfo says: > 1K blocks Used >/dev/wd0b 65536 64 >/dev/vn0b 1280 64 > >which is kind of curious, as the machine has 16 MB ram and almost >no activity going on... Swap partition, when in use, are always >reported with at least 64 KB in use. > >Is there any explaination ? The first swap block is always pre-allocated. This was done to work around a problem with people putting their swap partition at the beginning of their disk (the system would happily try to destroy the label). I suppose it would be better to change swapinfo/pstat to not include the first block of swap space in its report. -DG