From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 24 Mar 2008 11:31:05 -0700 (PDT) From: Christoph Lameter Subject: Re: [00/14] Virtual Compound Page Support V3 In-Reply-To: <20080322114043.17833ab4@laptopd505.fenrus.org> Message-ID: References: <20080321061703.921169367@sgi.com> <20080322114043.17833ab4@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Arjan van de Ven Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Sat, 22 Mar 2008, Arjan van de Ven wrote: > can you document the drawback of large, frequent vmalloc() allocations at least? Ok. Lets add some documentation about this issue and some other things. A similar suggestion was made by Kosaki-san. > On 32 bit x86, the effective vmalloc space is 64Mb or so (after various PCI bars are ioremaped), > so if this type of allocation is used for a "scales with nr of ABC" where "ABC" is workload dependent, > there's a rather abrupt upper limit to this. > Not saying that that is a flaw of your patch, just pointing out that we should discourage usage of > the "scales with nr of ABC" (for example "one for each thread") kind of things. I better take out any patches that do large scale allocs then. -- 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