From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264220AbTEGT1f (ORCPT ); Wed, 7 May 2003 15:27:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264253AbTEGT1e (ORCPT ); Wed, 7 May 2003 15:27:34 -0400 Received: from sj-core-2.cisco.com ([171.71.177.254]:13292 "EHLO sj-core-2.cisco.com") by vger.kernel.org with ESMTP id S264244AbTEGT1V (ORCPT ); Wed, 7 May 2003 15:27:21 -0400 From: "Hua Zhong" To: , "Davide Libenzi" Cc: "Linux kernel" Subject: RE: top stack (l)users for 2.5.69 Date: Wed, 7 May 2003 12:39:28 -0700 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.6604 (9.0.2911.0) In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V5.50.4925.2800 Importance: Normal Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > It is my understanding that there is one kernel stack. If there > is a stack allocated for some "transition", and I guess there > may be, because of the mail I'm getting, then it has absolutely > no purpose whatsoever and is wasted valuable non-paged RAM. I think your understanding is wrong. Each process has its own kernel stack allocated together with the task_struct in a 8K chunk. At least for 2.4 it is. I think interrupt handler also uses the current kernel stack. > The reason why system-call parameters are passed in registers > is so that we didn't have the overhead of copying stuff from a > user stack to a kernel stack. > > Does anybody know (not guess) if this was stuff added for the > new non-interrupt 0x80 syscall code? I want to know how a > simple kernel got corrupted into this twisted thing. > > Anybody who has a copy of any of the Intel manuals since '386 > knows that there needs to be only one kernel stack. > > Cheers, > Dick Johnson > Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips). > Why is the government concerned about the lunatic fringe? Think about it.