Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266097AbUFPDMt (ORCPT ); Tue, 15 Jun 2004 23:12:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266089AbUFPDLT (ORCPT ); Tue, 15 Jun 2004 23:11:19 -0400 Received: from fw.osdl.org ([65.172.181.6]:51077 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S266086AbUFPDJY (ORCPT ); Tue, 15 Jun 2004 23:09:24 -0400 Date: Tue, 15 Jun 2004 20:09:04 -0700 (PDT) From: Linus Torvalds To: Herbert Xu cc: "Martin J. Bligh" , mingo@elte.hu, kernel@kolivas.org, linux-kernel@vger.kernel.org, piggin@cyberone.com.au, akpm@osdl.org, wli@holomorphy.com, markw@osdl.org Subject: Re: [PATCH] Performance regression in 2.6.7-rc3 In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1263 Lines: 44 On Wed, 16 Jun 2004, Herbert Xu wrote: > > Martin J. Bligh wrote: > > > > How the hell can that have any effect on non-threaded workloads? Perhaps > > some part of kernel compile *is* multi-threaded. It does seem to get > > make(1) with vfork(2) perhaps? Very likely. And in the vfork() case it is definitely WRONG to try to reschedule (either threads _or_ processes), since the parent is going to go to sleep real soon now. I think this code: if (clone_flags & CLONE_VM) wake_up_forked_thread(p); else wake_up_forked_process(p); is just wrong, and it should be replaced with wake_up_new_process(p, clone_flags); and then "wake_up_new_process()" can do the right thing, which is basically: if (clone_flags & CLONE_VFORK) synchronous wakeup, same as pipe-will-block case else if (clone_flags & CLONE_VM) thread-wakeup-case else process-wakeup-case No? Linus - 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/