From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030468AbXDJHJU (ORCPT ); Tue, 10 Apr 2007 03:09:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030470AbXDJHJU (ORCPT ); Tue, 10 Apr 2007 03:09:20 -0400 Received: from srv5.dvmed.net ([207.36.208.214]:33269 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030468AbXDJHJT (ORCPT ); Tue, 10 Apr 2007 03:09:19 -0400 Message-ID: <461B3806.3010103@garzik.org> Date: Tue, 10 Apr 2007 03:08:54 -0400 From: Jeff Garzik User-Agent: Thunderbird 1.5.0.10 (X11/20070302) MIME-Version: 1.0 To: Torsten Kaiser CC: Andrew Morton , Dave Jones , Robin Holt , "Eric W. Biederman" , Ingo Molnar , Linus Torvalds , linux-kernel@vger.kernel.org, Jack Steiner Subject: Re: init's children list is long and slows reaping children. References: <20070405195118.GH22762@lnx-holt.americas.sgi.com> <4616CBF0.7090606@garzik.org> <20070409172339.48d661d6.akpm@linux-foundation.org> <20070410015912.GE1994@redhat.com> <20070409193056.6b52c354.akpm@linux-foundation.org> <64bb37e0704092309v49ae1ddbvb22e3f213ccab28e@mail.gmail.com> In-Reply-To: <64bb37e0704092309v49ae1ddbvb22e3f213ccab28e@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Score: -4.3 (----) X-Spam-Report: SpamAssassin version 3.1.8 on srv5.dvmed.net summary: Content analysis details: (-4.3 points, 5.0 required) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Torsten Kaiser wrote: > One thread per port, not per device. > > 796 ? S 0:00 \_ [scsi_eh_0] > 797 ? S 0:00 \_ [scsi_eh_1] > 798 ? S 0:00 \_ [scsi_eh_2] > 819 ? S 0:00 \_ [scsi_eh_3] > 820 ? S 0:00 \_ [scsi_eh_4] > 824 ? S 0:00 \_ [scsi_eh_5] > 825 ? S 0:14 \_ [scsi_eh_6] > > bardioc ~ # lsscsi -d > [0:0:0:0] disk ATA ST3160827AS 3.42 /dev/sda[8:0] > [1:0:0:0] disk ATA ST3160827AS 3.42 /dev/sdb[8:16] > [5:0:0:0] disk ATA IBM-DHEA-36480 HE8O /dev/sdc[8:32] > [5:0:1:0] disk ATA Maxtor 6L160P0 BAH4 /dev/sdd[8:48] > [6:0:0:0] cd/dvd HL-DT-ST DVDRAM GSA-4081B A100 /dev/sr0[11:0] > bardioc ~ # lsscsi -H > [0] sata_promise > [1] sata_promise > [2] sata_promise > [3] sata_via > [4] sata_via > [5] pata_via > [6] pata_via > > The bad is, that there is always a thread, even if the hardware is not > even hotplug capable. > Don't know if the thread is even needed for hotplug... Nope, it's not. At least for SATA (your chosen examples), hotplug is handled by a libata-specific thread. The SCSI EH threads are there purely for SCSI exception handling. For the majority of SAS and SATA, we replace the entire SCSI EH handling code with our own, making those threads less useful than on older (read: majority) of SCSI drivers. Jeff