Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 23 Apr 2001 16:45:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 23 Apr 2001 16:45:21 -0400 Received: from asterix.hrz.tu-chemnitz.de ([134.109.132.84]:35235 "EHLO asterix.hrz.tu-chemnitz.de") by vger.kernel.org with ESMTP id ; Mon, 23 Apr 2001 16:45:08 -0400 Date: Mon, 23 Apr 2001 22:45:05 +0200 From: Ingo Oeser To: Alexander Viro Cc: Christoph Rohland , "David L. Parsley" , linux-kernel@vger.kernel.org Subject: Re: hundreds of mount --bind mountpoints? Message-ID: <20010423224505.H719@nightmaster.csn.tu-chemnitz.de> In-Reply-To: <20010423172335.G719@nightmaster.csn.tu-chemnitz.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2i In-Reply-To: ; from viro@math.psu.edu on Mon, Apr 23, 2001 at 11:36:24AM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 23, 2001 at 11:36:24AM -0400, Alexander Viro wrote: > > Great idea. We allocate this space anyway. And we don't have to > > care about the internals of this union, because never have to use > > it outside the kernel ;-) > > > > I like it. ext2fs does the same, so there should be no VFS > > hassles involved. Al? > > We should get ext2 and friends to move the sucker _out_ of struct inode. > As it is, sizeof(struct inode) is way too large. This is 2.5 stuff, but > it really has to be done. More filesystems adding stuff into the union > is a Bad Thing(tm). If you want to allocates space - allocate if yourself; > ->clear_inode() is the right place for freeing it. You need an inode anyway. So why not using the space in it? tmpfs would only use sizeof(*inode.u)-sizeof(struct shmem_inode_info) for this kind of symlinks. Last time we suggested this, people ended up with some OS trying it and getting worse performance. Why? You need to allocate the VFS-inode (vnode in other OSs) and the on-disk-inode anyway at the same time. You get better performance and less fragmentation, if you allocate them both together[1]. So that struct inode around is ok. BTW: Is it still less than one page? Then it doesn't make me nervous. Why? Guess what granularity we allocate at, if we just store pointers instead of the inode.u. Or do you like every FS creating his own slab cache? Regards Ingo Oeser [1] Which is true for other allocations, too. -- 10.+11.03.2001 - 3. Chemnitzer LinuxTag <<<<<<<<<<<< been there and had much fun >>>>>>>>>>>> - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/