From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 29 Jan 2007 17:41:18 -0800 From: Andrew Morton Subject: Re: [PATCH] mm: remove global locks from mm/highmem.c Message-Id: <20070129174118.0e922ab3.akpm@osdl.org> In-Reply-To: <45BE9FE8.4080603@mbligh.org> References: <1169993494.10987.23.camel@lappy> <20070128142925.df2f4dce.akpm@osdl.org> <1170063848.6189.121.camel@twins> <45BE9FE8.4080603@mbligh.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: "Martin J. Bligh" Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ingo Molnar List-ID: On Mon, 29 Jan 2007 17:31:20 -0800 "Martin J. Bligh" wrote: > Peter Zijlstra wrote: > > On Sun, 2007-01-28 at 14:29 -0800, Andrew Morton wrote: > > > >> As Christoph says, it's very much preferred that code be migrated over to > >> kmap_atomic(). Partly because kmap() is deadlockable in situations where a > >> large number of threads are trying to take two kmaps at the same time and > >> we run out. This happened in the past, but incidences have gone away, > >> probably because of kmap->kmap_atomic conversions. > > > >> From which callsite have you measured problems? > > > > CONFIG_HIGHPTE code in -rt was horrid. I'll do some measurements on > > mainline. > > > > CONFIG_HIGHPTE is always horrid -we've known that for years. We have? What's wrong with it? > Don't use it. > > If that's all we're fixing here, I'd be highly suspect ... highpte uses atomic kmaps - it is unrelated to this work. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org