Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH 1/3] introduce PF_KTHREAD flag | Date | Tue, 24 Jun 2008 22:51:22 +0200 |
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On Tuesday, 24 of June 2008, Oleg Nesterov wrote: > On 06/23, Andrew Morton wrote: > > > > On Mon, 23 Jun 2008 13:47:06 -0700 > > Andrew Morton <akpm@linux-foundation.org> wrote: > > > > > I don't yet know how much additional damage will happen as a result. > > > > Lots. > > > > I restored the patches and just dropped the hunk: > > > > static int has_mm(struct task_struct *p) > > { > > - return (p->mm && !(p->flags & PF_BORROWED_MM)); > > } > > > > /** > > --- 86,92 ---- > > > > static int has_mm(struct task_struct *p) > > { > > + return (p->mm && !(p->flags & PF_KTHREAD)); > > } > > > > due to that function having been turned into: > > > > static inline bool should_send_signal(struct task_struct *p) > > { > > return !(p->flags & PF_FREEZER_NOSIG); > > } > > > > Please check the result? > > Thanks, this looks OK. > > Rafael, can't freezer just use PF_KTHREAD (which btw kills PF_BORROWED_MM) > instead of the new PF_FREEZER_NOSIG flag? They look very similar, please > look at > > "[PATCH 1/3] introduce PF_KTHREAD flag" > http://marc.info/?l=linux-kernel&m=121233423530812 > > "[PATCH 2/3] kill PF_BORROWED_MM in favour of PF_KTHREAD" > http://marc.info/?l=linux-kernel&m=121233423530820
The problem is that some kernel threads may actually want to clear PF_FREEZER_NOSIG, but it would be invalid to clear PF_KTHREAD I think.
Hmm, well, in principle we could use two flags for that, with the combinations of bits defined as follows: 11 - user space task (freezable with a fake signal) 10 - kernel thread freezable with a fake signal 01 - kernel thread freezable withoug a fake signal 00 - non-freezable kernel thread
Thanks, Rafael
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