Messages in this thread | | | Subject | Re: slab: setup allocators earlier in the boot sequence | From | Pekka Enberg <> | Date | Fri, 12 Jun 2009 10:59:52 +0300 |
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Hi Nick,
On Fri, Jun 12, 2009 at 10:45:45AM +0300, Pekka Enberg wrote: > > On Fri, 2009-06-12 at 17:34 +1000, Benjamin Herrenschmidt wrote: > > > I really believe this should be a slab internal thing, which is what my > > > patch does to a certain extent. IE. All callers need to care about is > > > KERNEL vs. ATOMIC and in some cases, NOIO or similar for filesystems > > > etc... but I don't think all sorts of kernel subsystems, because they > > > can be called early during boot, need to suddenly use GFP_NOWAIT all the > > > time. > > > > > > That's why I much prefer my approach :-) (In addition to the fact that > > > it provides the basis for also fixing suspend/resume). > > > > Sure, I think we can do what you want with the patch below.
On Fri, 2009-06-12 at 09:54 +0200, Nick Piggin wrote: > I don't really like adding branches to slab allocator like this. > init code all needs to know what services are available, and > this includes the scheduler if it wants to do anything sleeping > (including sleeping slab allocations). > > Core mm code is the last place to put in workarounds for broken > callers...
Yes, the initialization code can be fixed to use GFP_NOWAIT. But it's really the suspend case that makes me think the patch might be a good idea. So the patch does not attempt to be a workaround for buggy callers but rather a change in policy that we simply refuse to wait during bootup and suspend.
Pekka
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