Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934244AbXEHQlM (ORCPT ); Tue, 8 May 2007 12:41:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934094AbXEHQlK (ORCPT ); Tue, 8 May 2007 12:41:10 -0400 Received: from e6.ny.us.ibm.com ([32.97.182.146]:32902 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934068AbXEHQlI (ORCPT ); Tue, 8 May 2007 12:41:08 -0400 Date: Tue, 8 May 2007 22:18:50 +0530 From: Srivatsa Vaddagiri To: Satoru Takeuchi Cc: Rusty Russell , Linux Kernel , Zwane Mwaikambo , Nathan Lynch , Joel Schopp , Ashok Raj , Heiko Carstens , Gautham R Shenoy , Ingo Molnar , paulmck@us.ibm.com Subject: Re: [BUG] cpu-hotplug: Can't offline the CPU with naughty realtime processes Message-ID: <20070508164850.GS7311@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <87bqgxrlky.wl%takeuchi_satoru@jp.fujitsu.com> <1178545373.28438.7.camel@localhost.localdomain> <877irkrq8a.wl%takeuchi_satoru@jp.fujitsu.com> <1178593345.28438.29.camel@localhost.localdomain> <874pmoro1c.wl%takeuchi_satoru@jp.fujitsu.com> <20070508041033.GB25030@in.ibm.com> <87irb3g4zt.wl%takeuchi_satoru@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87irb3g4zt.wl%takeuchi_satoru@jp.fujitsu.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1599 Lines: 39 On Tue, May 08, 2007 at 04:16:06PM +0900, Satoru Takeuchi wrote: > Sometimes I wonder at prio_array. It has 140 entries(from 0 to 139), > and the meaning of each entry is as follows, I think. > > +-----------+-----------------------------------------------+ > | index | usage | > +-----------+-----------------------------------------------+ > | 0 - 98 | RT processes are here. They are in the entry | > | | whose index is 99 - sched_priority. | >From sched.h: /* * Priority of a process goes from 0..MAX_PRIO-1, valid RT * priority is 0..MAX_RT_PRIO-1, and SCHED_NORMAL/SCHED_BATCH * tasks are in the range MAX_RT_PRIO..MAX_PRIO-1. so shouldn't the index for RT processes be 0 - 99, given that MAX_RT_PRIO = 100? > +-----------+-----------------------------------------------+ > | 99 | No one use it? CMIIW. | > +-----------+-----------------------------------------------+ > | 100 - 139 | Ordinally processes are here. They are in the | > | | entry whose index is (nice+120) +/- 5 | > +-----------+-----------------------------------------------+ > > What's the purpose of the prio_array[99]? Once I exlore source tree > briefly and can't found any kernel thread which uses this entry. > Does anybody know? -- Regards, vatsa - 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/