Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sat, 13 Oct 2001 17:24:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sat, 13 Oct 2001 17:24:08 -0400 Received: from [202.135.142.194] ([202.135.142.194]:36365 "EHLO haven.ozlabs.ibm.com") by vger.kernel.org with ESMTP id ; Sat, 13 Oct 2001 17:24:02 -0400 From: Rusty Russell To: Linus Torvalds Cc: dipankar@beaverton.ibm.com, linux-kernel@vger.kernel.org Subject: Re: [Lse-tech] Re: RFC: patch to allow lock-free traversal of lists with insertion In-Reply-To: Your message of "Sat, 13 Oct 2001 10:23:23 PDT." Date: Sun, 14 Oct 2001 07:19:54 +1000 Message-Id: Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org In message you write: > > (b) the whole notiong of "scheduling point" is a lot too fragile to be > acceptable for important data structures. It breaks with the > pre-emption patches on UP, and we've seen many times how hard it is > for developers to notice even when there _is_ an explicit "end > critical region now" kind of thing Yeah, if you can't get locking right, you can't get RCU right. I've shown you that using it in place of standard locking is simple: the ONLY added issue is being careful not to screw readers while doing the actual insert/delete. Where, if anywhere, is this worth it? Good question: 3% on 4-way dbench doesn't cut it in my book... Rusty. -- Premature optmztion is rt of all evl. --DK - 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/