Messages in this thread | | | Date | Thu, 21 Jun 2007 22:23:14 +0200 | From | Ingo Molnar <> | Subject | Re: [BUG] long freezes on thinkpad t60 |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Thu, 21 Jun 2007, Ingo Molnar wrote: > > > > I can understand why no data is saved by this change: gcc is > > aligning the next field to a natural boundary anyway and we dont > > really have arrays of spinlocks (fortunately). > > Actually, some data structures could well shrink. > > Look at "struct task_struct", for example. Right now it has two > spinlocks right next to each other (alloc_lock and pi_lock).
yeah. We've got init_task's task-struct embedded in the vmlinux, but it's aligned to 32 bytes, which probably hides this effect. We'd only see it if the size change just happened to bring a key data structure (which is also embedded in the vmlinux) just below a modulo 32 bytes boundary. The chance for that is around 6:32 per 'merge' event. That means that there cannot be all that many such cases ;-)
anyway, the shorter init sequence is worth it already.
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