Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261330AbUKSJql (ORCPT ); Fri, 19 Nov 2004 04:46:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261222AbUKSJqk (ORCPT ); Fri, 19 Nov 2004 04:46:40 -0500 Received: from gprs214-9.eurotel.cz ([160.218.214.9]:48513 "EHLO amd.ucw.cz") by vger.kernel.org with ESMTP id S261191AbUKSJqf (ORCPT ); Fri, 19 Nov 2004 04:46:35 -0500 Date: Fri, 19 Nov 2004 10:46:20 +0100 From: Pavel Machek To: Miklos Szeredi Cc: torvalds@osdl.org, alan@lxorguk.ukuu.org.uk, hbryan@us.ibm.com, akpm@osdl.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [Request for inclusion] Filesystem in Userspace Message-ID: <20041119094620.GA32322@elf.ucw.cz> References: <1100798975.6018.26.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1323 Lines: 31 Hi! > > The GFP_IO and GFP_FS pages are the _real_ protectors. They don't dip into > > the (very limited) set of pages, they say "we can still free 90% of > > memory, we just have to ignore that dangerous 10%". > > I don't see how this makes more problems to userspace filesystems. > When you clear GFP_IO or GFP_FS for an allocation you are limiting > yourself from freeing some sort of memory. But that will not make it > easier to actually _get_ that memory. > > With FUSE the allocation is NOT limited. Deadlock will not happen > since page writeback is non-blocking, so while more FUSE backed pages > can't be written, other filesystem's pages can be written back. The > situation is better not worse. > > What am I missing? I believe problem is when there are no other filesystem's pages.... and at that point FUSE is worse than kernel filesystems because you do not have reserved pools to use for freeing memory. Pavel -- People were complaining that M$ turns users into beta-testers... ...jr ghea gurz vagb qrirybcref, naq gurl frrz gb yvxr vg gung jnl! - 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/