[4/4] SLAB: Fix node add timer race in cache_reap
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From: Andi Kleen on 26 Feb 2010 09:10 On Fri, Feb 26, 2010 at 02:35:24PM +0200, Pekka Enberg wrote: > On Fri, Feb 26, 2010 at 1:43 PM, Andi Kleen <andi(a)firstfloor.org> wrote: > > On Fri, Feb 26, 2010 at 12:45:02PM +0200, Pekka Enberg wrote: > >> Christoph Lameter kirjoitti: > >>>> kmalloc_node() in generic kernel code. �All that is done under > >>>> MEM_GOING_ONLINE and not MEM_ONLINE, which is why I suggest the first and > >>>> fourth patch in this series may not be necessary if we prevent setting the > >>>> bit in the nodemask or building the zonelists until the slab nodelists are > >>>> ready. > >>> > >>> That sounds good. > >> > >> Andi? > > > > Well if Christoph wants to submit a better patch that is tested and solves > > the problems he can do that. > > Sure. > > > if he doesn't then I think my patch kit which has been tested > > is the best alternative currently. > > So do you expect me to merge your patches over his objections? Let's put it like this: i'm sure there a myriad different way in all the possible design spaces to change slab to make memory hotadd work. Unless someone gives me a strong reason (e.g. code as submitted doesn't work or is really unclean) I'm not very motivated to try them all (also given that slab.c is really legacy code that will hopefully go away at some point). Also there are still other bugs to fix in memory hotadd and I'm focussing my efforts on that. I don't think the patches I submitted are particularly intrusive or unclean or broken. As far as I can see Christoph's proposal was just another way to do this, but it wasn't clear to me it was better enough in any way to spend significant time on it. So yes I would prefer if you merged them as submitted just to fix the bugs. If someone else comes up with a better way to do this and submits patches they could still change to that later. As for the timer race patch: I cannot make a strong argument right now that it's needed, on the other hand a bit of defensive programming also doesn't hurt. But if that one is not in I won't cry. -Andi -- ak(a)linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Christoph Lameter on 26 Feb 2010 10:10 On Fri, 26 Feb 2010, Andi Kleen wrote: > Memory hotplug with node add never quite worked on x86 before, > for various reasons not related to slab. Ok but why did things break in such a big way? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Christoph Lameter on 26 Feb 2010 10:10 I mean why the core changes if this is an x86 issue? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andi Kleen on 26 Feb 2010 11:00 On Fri, Feb 26, 2010 at 09:05:48AM -0600, Christoph Lameter wrote: > > I mean why the core changes if this is an x86 issue? The slab bugs are in no way related to x86, other than x86 supporting memory hotadd & numa. I only wrote "on x86" because I wasn't sure about the status on the other platforms. -Andi -- ak(a)linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
From: Andi Kleen on 26 Feb 2010 11:00
On Fri, Feb 26, 2010 at 09:04:56AM -0600, Christoph Lameter wrote: > On Fri, 26 Feb 2010, Andi Kleen wrote: > > > Memory hotplug with node add never quite worked on x86 before, > > for various reasons not related to slab. > > Ok but why did things break in such a big way? 1) numa memory hotadd never worked 2) the rest just bitrotted because nobody tested it. -Andi -- ak(a)linux.intel.com -- Speaking for myself only. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |