On Fri, Sep 08, 2017 at 07:35:37AM -0700, Tejun Heo wrote: > Hello, > > On Wed, Sep 06, 2017 at 07:00:51PM -0700, Shaohua Li wrote: > > +#ifdef CONFIG_CGROUPS > > +void kthread_set_orig_css(struct cgroup_subsys_state *css); > > +struct cgroup_subsys_state *kthread_get_orig_css(void); > > +void kthread_reset_orig_css(void); > > * It's a bit weird to associate a kthread with a css without being > specific. If what's needed is a generic association (this kthread > is temporarily servicing this cgroup), it should be associated with > the cgroup. But, I think it'd be better to make it specific instead > - ie. kthread_set_io_css(). > > * Do we need the reset function to be separate? Can't we just clear > it when the set function is called with NULL css? > > * For the accessor, can we do sth like kthread_orig_css() (or > kthread_io_css())? "get" is overloaded between set/get and get/put, > so it can get confusing. > > > diff --git a/include/linux/sched.h b/include/linux/sched.h > > index c05ac5f..ab2295d 100644 > > --- a/include/linux/sched.h > > +++ b/include/linux/sched.h > > @@ -1276,6 +1276,7 @@ extern struct pid *cad_pid; > > #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ > > #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_allowed */ > > #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ > > +#define PF_KTHREAD_HAS_CSS 0x10000000 /* kthread has css info attached */ > > Do we need a separate flag for this? kthreads already have PF_KTHREAD > set. I'm not sure why we'd need another flag. Once we know it's a > kthread, we can just access its css pointer field, right? Ok, all suggestions are good, will update. Thanks, Shaohua
