Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758067AbYB2F5q (ORCPT ); Fri, 29 Feb 2008 00:57:46 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752083AbYB2F5i (ORCPT ); Fri, 29 Feb 2008 00:57:38 -0500 Received: from E23SMTP02.au.ibm.com ([202.81.18.163]:39741 "EHLO e23smtp02.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983AbYB2F5h (ORCPT ); Fri, 29 Feb 2008 00:57:37 -0500 Date: Fri, 29 Feb 2008 11:27:30 +0530 From: Dhaval Giani To: Peter Zijlstra Cc: Srivatsa Vaddagiri , Ingo Molnar , Sudhir Kumar , Balbir Singh , Aneesh Kumar KV , lkml , vgoyal@redhat.com, serue@us.ibm.com, menage@google.com Subject: Re: [RFC, PATCH 1/2] sched: allow the CFS group scheduler to have multiple levels Message-ID: <20080229055730.GA5478@linux.vnet.ibm.com> Reply-To: Dhaval Giani References: <20080225141504.GA27746@linux.vnet.ibm.com> <20080225141703.GB29213@linux.vnet.ibm.com> <1204227766.6243.41.camel@lappy> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1204227766.6243.41.camel@lappy> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4248 Lines: 125 On Thu, Feb 28, 2008 at 08:42:46PM +0100, Peter Zijlstra wrote: > > On Mon, 2008-02-25 at 19:47 +0530, Dhaval Giani wrote: > > This patch makes the group scheduler multi hierarchy aware. > > Ok, good thing to do in principle > thanks! > > Signed-off-by: Dhaval Giani > > > > --- > > include/linux/sched.h | 2 +- > > kernel/sched.c | 41 ++++++++++++++++++++++++----------------- > > 2 files changed, 25 insertions(+), 18 deletions(-) > > > > Index: linux-2.6.25-rc2/include/linux/sched.h > > =================================================================== > > --- linux-2.6.25-rc2.orig/include/linux/sched.h > > +++ linux-2.6.25-rc2/include/linux/sched.h > > @@ -2031,7 +2031,7 @@ extern void normalize_rt_tasks(void); > > > > extern struct task_group init_task_group; > > > > -extern struct task_group *sched_create_group(void); > > +extern struct task_group *sched_create_group(struct task_group *parent); > > extern void sched_destroy_group(struct task_group *tg); > > extern void sched_move_task(struct task_struct *tsk); > > #ifdef CONFIG_FAIR_GROUP_SCHED > > Index: linux-2.6.25-rc2/kernel/sched.c > > =================================================================== > > --- linux-2.6.25-rc2.orig/kernel/sched.c > > +++ linux-2.6.25-rc2/kernel/sched.c > > @@ -7155,10 +7155,11 @@ static void init_rt_rq(struct rt_rq *rt_ > > } > > > > #ifdef CONFIG_FAIR_GROUP_SCHED > > -static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg, > > - struct cfs_rq *cfs_rq, struct sched_entity *se, > > - int cpu, int add) > > +static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, > > + struct sched_entity *se, int cpu, int add, > > + struct sched_entity *parent) > > { > > + struct rq *rq = cpu_rq(cpu); > > tg->cfs_rq[cpu] = cfs_rq; > > init_cfs_rq(cfs_rq, rq); > > cfs_rq->tg = tg; > > @@ -7170,7 +7171,11 @@ static void init_tg_cfs_entry(struct rq > > if (!se) > > return; > > > > - se->cfs_rq = &rq->cfs; > > + if (parent == NULL) > > !parent ? > Will do. (need to start remembering to doing this one!) > > + se->cfs_rq = &rq->cfs; > > + else > > + se->cfs_rq = parent->my_q; > > + > > se->my_q = cfs_rq; > > se->load.weight = tg->shares; > > se->load.inv_weight = div64_64(1ULL<<32, se->load.weight); > > @@ -7244,7 +7249,8 @@ void __init sched_init(void) > > * We achieve this by letting init_task_group's tasks sit > > * directly in rq->cfs (i.e init_task_group->se[] = NULL). > > */ > > - init_tg_cfs_entry(rq, &init_task_group, &rq->cfs, NULL, i, 1); > > + init_tg_cfs_entry(&init_task_group, &rq->cfs, > > + NULL, i, 1, NULL); > > init_tg_rt_entry(rq, &init_task_group, &rq->rt, NULL, i, 1); > > #elif defined CONFIG_USER_SCHED > > /* > > @@ -7260,7 +7266,7 @@ void __init sched_init(void) > > */ > > init_tg_cfs_entry(rq, &init_task_group, > > &per_cpu(init_cfs_rq, i), > > - &per_cpu(init_sched_entity, i), i, 1); > > + &per_cpu(init_sched_entity, i), i, 1, NULL); > > > > #endif > > #endif /* CONFIG_FAIR_GROUP_SCHED */ > > @@ -7630,7 +7636,8 @@ static void free_fair_sched_group(struct > > kfree(tg->se); > > } > > > > -static int alloc_fair_sched_group(struct task_group *tg) > > +static int alloc_fair_sched_group(struct task_group *tg, > > + struct task_group *parent) > > { > > struct cfs_rq *cfs_rq; > > struct sched_entity *se; > > @@ -7658,8 +7665,11 @@ static int alloc_fair_sched_group(struct > > GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); > > if (!se) > > goto err; > > - > > - init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0); > > + if (!parent) { > > + init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]); > > + } else { > > + init_tg_cfs_entry(tg, cfs_rq, se, i, 0, NULL); > > + } > > Looks like you got the cases switched, this looks like an instant NULL > deref. > eeeks! Yeah, you are right. Funny though how I did not hit it while testing. -- regards, Dhaval -- 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/