From owner-freebsd-hackers Thu Mar 7 8:43:11 2002 Delivered-To: freebsd-hackers@freebsd.org Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by hub.freebsd.org (Postfix) with ESMTP id 11A7F37B420 for ; Thu, 7 Mar 2002 08:43:00 -0800 (PST) Received: by elvis.mu.org (Postfix, from userid 1192) id DAAE9AE1FC; Thu, 7 Mar 2002 08:42:59 -0800 (PST) Date: Thu, 7 Mar 2002 08:42:59 -0800 From: Alfred Perlstein To: Jan Grant Cc: freebsd-hackers@freebsd.org Subject: Re: Bug? still looking, yet to knock up small test case. Suggestions solicited. Message-ID: <20020307164259.GE26621@elvis.mu.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.3.27i Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * Jan Grant [020307 08:12] wrote: > Something odd seems to be happening; I'd appreciate "look here" > suggestions. I suspect mmapped pages aren't being flushed but gawd alone > knows why. > > Situation: vmware2, with a "fake disk", files in the /external FS > (/external/vmware1/nt1.*). > > FBSD-stable. Behaviour's been like this for quite some time (since > around 4.3-release, I think) [snip] > Note: this doesn't result in ultimately broken behaviour, because those > pages are eventually flushed on orderly shutdown. I'm just curious as to > why sync(2) isn't forcing this. Afaik this is a "feature" of Linux that the emulator tries to emulate. From what I've _heard_ (not witnessed), Linux doesn't have the syncer flush mmap(2)'d data on a regular basis, so in FreeBSD we emulate this behaviour and you get the behaviour you've been seeing. Since, sync(2) schedules the syncer to sync out the buffers which are marked for ignore by the syncer you don't see anything being done. :) -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message