From mboxrd@z Thu Jan 1 00:00:00 1970 From: Libor Vanek Subject: Re: [Iscsitarget-devel] Re: [ANNOUNCE] iSCSI enterprise target software Date: Tue, 01 Mar 2005 11:48:22 +0100 Message-ID: <42244876.9000204@terra.cz> References: <1109666441.6293.62.camel@laptopd505.fenrus.org> <20050301183549J.fujita.tomonori@lab.ntt.co.jp> <1109670363.6293.70.camel@laptopd505.fenrus.org> <20050301192257C.fujita.tomonori@lab.ntt.co.jp> <1109673220.6293.78.camel@laptopd505.fenrus.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Received: from ms.terra.cz ([212.71.159.130]:20237 "EHLO terra.cz") by vger.kernel.org with ESMTP id S261858AbVCAKsg (ORCPT ); Tue, 1 Mar 2005 05:48:36 -0500 Received: from [192.168.0.32] by terra.cz (MDaemon.PRO.v7.2.3.R) with ESMTP id md50000023831.msg for ; Tue, 01 Mar 2005 11:47:16 +0100 In-Reply-To: <1109673220.6293.78.camel@laptopd505.fenrus.org> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Arjan van de Ven Cc: FUJITA Tomonori , linux-scsi@vger.kernel.org, iscsitarget-devel@lists.sourceforge.net Arjan van de Ven wrote: >On Tue, 2005-03-01 at 19:22 +0900, FUJITA Tomonori wrote: > > >>From: Arjan van de Ven >>Subject: [Iscsitarget-devel] Re: [ANNOUNCE] iSCSI enterprise target software >>Date: Tue, 01 Mar 2005 10:46:03 +0100 >> >> >> >>>fsync or msync() ? I would imagine the target mmaping it's backend in >>>userspace and using msync() to kick off IO. At which point it's not that >>>much different from the control you do of the pagecache from inside the >>>kernel... >>> >>> >>Can we avoid calling mmap() and munmap() repeatedly with large disk? >> >> > >my server has 512Gb address space with 2.6.9/2.6.10, and a lot more than >that with the 2.6.11 kernel (4 level page tables rock). So the answer >would be yes. > >(and on old servers without 64 bit, you indeed need to mmap/munmap >lazily to create a window, but I suspect that the 3 Gb of address space >you have there can be managed smart to minimize the number of unmaps if >you really try) > > I don't know in detail what are you talking about (if whole disk must fit address space) but please consider we're speaking about TBs (10-20 TB RAID is quite cheap nowadays with 400 GB SATA disks). -- Best regards, Libor Vanek