Messages in this thread |  | | | Date | Fri, 10 Sep 2010 10:59:41 +0200 | | Subject | Re: [RFC PATCH 1/2] perf_events: add support for per-cpu per-cgroup monitoring (v3) | | From | Stephane Eranian <> |
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On Fri, Sep 10, 2010 at 10:41 AM, Tejun Heo <tj@kernel.org> wrote: > > Hello, > > On 09/10/2010 10:16 AM, Peter Zijlstra wrote: > > On Thu, 2010-09-09 at 23:41 +0200, Stephane Eranian wrote: > >>> alloc_percpu() is zalloc_percpu() in fact, memory is already cleared. > >>> > >> I remember thinking about this and trying to trace to the code down > >> to figure this out. But it is rather complicated. If alloc_percpu() always > >> clears the memory, then I think that calling is zalloc_percpu() > >> would be more helpful.... > > Maybe but at this point it might be a bit too late. The allocator has > been that way since the beginning. > Then add a comment in the header or at the definition of the function to make this more explicit.
> > pcpu_populate_chunk() in mm/percpu-vm.c does indeed do that memset, the > > one in mm/percpu-km.c does not. > > > > It is not obviously clear to me the -km allocator does indeed result in > > zero filled memory. > > Nice catch. Fortunately, the -km allocator isn't currently being used > in upstrea although it was enabled for linux-next a couple of days > ago. I'll fix it up. > > Thank you. > > -- > tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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