Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [PATCH 3/6] cpuset: convert cpuset_attach() to use cpumask_var_t | Date | Wed, 7 Jan 2009 12:34:50 +1030 |
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On Monday 05 January 2009 19:31:47 Andrew Morton wrote: > On Mon, 05 Jan 2009 16:47:21 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote: > > > Allocate a global cpumask_var_t at boot, and use it in cpuset_attach(), so > > we won't fail cpuset_attach(). > > > > Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> > > Acked-by: Mike Travis <travis@sgi.com> > > --- > > kernel/cpuset.c | 14 +++++++++----- > > 1 files changed, 9 insertions(+), 5 deletions(-) > > > > diff --git a/kernel/cpuset.c b/kernel/cpuset.c > > index afa29cf..1e32e6b 100644 > > --- a/kernel/cpuset.c > > +++ b/kernel/cpuset.c > > @@ -1306,6 +1306,9 @@ static int fmeter_getrate(struct fmeter *fmp) > > return val; > > } > > > > +/* Protected by cgroup_lock */ > > +static cpumask_var_t cpus_attach; > > + > > /* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */ > > static int cpuset_can_attach(struct cgroup_subsys *ss, > > struct cgroup *cont, struct task_struct *tsk) > > @@ -1330,7 +1333,6 @@ static void cpuset_attach(struct cgroup_subsys *ss, > > struct cgroup *cont, struct cgroup *oldcont, > > struct task_struct *tsk) > > { > > - cpumask_t cpus; > > nodemask_t from, to; > > struct mm_struct *mm; > > struct cpuset *cs = cgroup_cs(cont); > > @@ -1338,13 +1340,13 @@ static void cpuset_attach(struct cgroup_subsys *ss, > > int err; > > > > if (cs == &top_cpuset) { > > - cpus = cpu_possible_map; > > + cpumask_copy(cpus_attach, cpu_possible_mask); > > } else { > > mutex_lock(&callback_mutex); > > - guarantee_online_cpus(cs, &cpus); > > + guarantee_online_cpus(cs, cpus_attach); > > mutex_unlock(&callback_mutex); > > } > > - err = set_cpus_allowed_ptr(tsk, &cpus); > > + err = set_cpus_allowed_ptr(tsk, cpus_attach); > > if (err) > > return; > > > > @@ -1357,7 +1359,6 @@ static void cpuset_attach(struct cgroup_subsys *ss, > > cpuset_migrate_mm(mm, &from, &to); > > mmput(mm); > > } > > - > > } > > > > /* The various types of files and directories in a cpuset file system */ > > @@ -1838,6 +1839,9 @@ int __init cpuset_init(void) > > if (err < 0) > > return err; > > > > + if (!alloc_cpumask_var(&cpus_attach, GFP_KERNEL)) > > + BUG(); > > + > > number_of_cpusets = 1; > > return 0; > > } > > OK, that works. > > Do we need to dynamically allocate cpus_attach? Can we just do > > static cpumask_t cpus_attach;
Well, (1) we're deprecating the typedef, (2) we really want the NR_CPUS=16384 and nr_cpu_ids=4 case not to suck and this sets a bad example, but moreover (3) struct cpumask won't be defined eventually when CONFIG_CPUMASKS_OFFSTACK=y so that won't compile.
Cheers, Rusty.
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