Date: Mon, 07 Oct 2002 14:25:45 -0700 From: Peter Wemm <peter@wemm.org> To: Mikhail Teterin <mi+mx@aldan.algebra.com> Cc: arch@FreeBSD.org Subject: Re: swapon some regular file Message-ID: <20021007212545.C363B2A88D@canning.wemm.org> In-Reply-To: <200210071630.42512.mi%2Bmx@aldan.algebra.com>
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Mikhail Teterin wrote: > Currently, swapon(2) will only succeed if the argument vn_isdisk(9), or > if it is an NFS-accessed file. > > Users wishing to swap onto a local regular file have to go through the > vnconfig/mdconfig gimnastics. Is that intentional? Yes, it is quite intentional. swap_pager doesn't have the code to do logical to physical translation that file IO would require. And the VOP_BMAP calls that do that add new complications, including an additional place it can sleep or run out of memory. We can get away with it for swapping to a file over NFS because the remote server does the translation, not us. In reality, what is required is some careful cut/paste of code from vnode_pager to swap_pager to add the missing bits, and some care to deal with the complications. vnconfig/mdconfig work because that basically adds the logical -> physical translation step. I'd just as soon not have to mess with this though. Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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