Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263184AbTEGMA5 (ORCPT ); Wed, 7 May 2003 08:00:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263185AbTEGMA5 (ORCPT ); Wed, 7 May 2003 08:00:57 -0400 Received: from holomorphy.com ([66.224.33.161]:62862 "EHLO holomorphy") by vger.kernel.org with ESMTP id S263184AbTEGMA4 (ORCPT ); Wed, 7 May 2003 08:00:56 -0400 Date: Wed, 7 May 2003 05:13:19 -0700 From: William Lee Irwin III To: "Martin J. Bligh" Cc: Paul Mackerras , Rusty Russell , Andrew Morton , dipankar@in.ibm.com, linux-kernel@vger.kernel.org, Bartlomiej Zolnierkiewicz Subject: Re: [PATCH] kmalloc_percpu Message-ID: <20030507121319.GA8978@holomorphy.com> Mail-Followup-To: William Lee Irwin III , "Martin J. Bligh" , Paul Mackerras , Rusty Russell , Andrew Morton , dipankar@in.ibm.com, linux-kernel@vger.kernel.org, Bartlomiej Zolnierkiewicz References: <20030506014745.02508f0d.akpm@digeo.com> <20030507023126.12F702C019@lists.samba.org> <20030507024135.GW8978@holomorphy.com> <16056.34210.319959.255815@argo.ozlabs.ibm.com> <20030507042250.GX8978@holomorphy.com> <16056.37397.694764.303333@argo.ozlabs.ibm.com> <20030507051901.GY8978@holomorphy.com> <4960000.1052280622@[10.10.2.4]> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4960000.1052280622@[10.10.2.4]> Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1267 Lines: 25 At some point in the past, my attribution was stripped from: >> Not as bad as it initially sounds; on non-PAE i386, it's 4KB and would >> hurt. On PAE i386, it's 32B and can be shoehorned, say, in thread_info. >> Then the rest is just a per-cpu kernel pmd and properly handling vmalloc >> faults (which are already handled properly for non-PAE vmallocspace). >> There might be other reasons to do it, like reducing the virtualspace >> overhead of the atomic kmap area, but it's not really time yet. On Tue, May 06, 2003 at 09:10:24PM -0700, Martin J. Bligh wrote: > Even if the space isn't a problem, having a full TLB flush on thread > context switch sounds sucky. Per-node is sufficient for most things, > and is much cheaper (update on cross-node migrate). The scheme described requires no TLB flushing or pgd switching when switching between threads in the same mm. Providing a true per-thread mapping, like one for the stack, might require an invlpg or two at each switch, but that wasn't mentioned here. -- wli - 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/