Messages in this thread | | | Date | Thu, 18 Feb 2010 19:25:19 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH hw_breakpoint] percpu: add __percpu sparse annotations to hw_breakpoint |
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On Thu, Feb 18, 2010 at 09:49:08AM +0900, Tejun Heo wrote: > Hello, > > On 02/18/2010 01:39 AM, Frederic Weisbecker wrote: > > On Wed, Feb 17, 2010 at 10:50:50AM +0900, Tejun Heo wrote: > > Yeah, looks good, I'm queuing it. > > Just few comments below, for nano-considerations. > >> cpu_events = alloc_percpu(typeof(*cpu_events)); > >> if (!cpu_events) > >> - return ERR_PTR(-ENOMEM); > >> + return (void __percpu __force *)ERR_PTR(-ENOMEM); > > > > Is this pattern common enough that we can think about a ERR_CPU_PTR ? > > I thought about that but there aren't too many yet, so I just added > the ugly castings. It would be cool if sparse can be taught that > ERR_PTR() returns universal pseudo pointer.
Yeah, it would be nice to just have a universal address space that is compatible with all others. It's sad to see such uglification to make a secondary tool happy.
> >> sample_hbp = register_wide_hw_breakpoint(&attr, sample_hbp_handler); > >> - if (IS_ERR(sample_hbp)) { > >> - ret = PTR_ERR(sample_hbp); > >> + if (IS_ERR((void __force *)sample_hbp)) { > >> + ret = PTR_ERR((void __force *)sample_hbp); > > > > Same comments here, although I wouldn't like much a CPU_PTR_ERR or > > IS_ERR_CPU.... CPP is just so poor in magic for that. > > > > I must confess I miss a bit the old per_cpu prefix that guarded the implicit > > separate namespace. > > Yeap, I agree that the prefix had its advantages. It's just that it > can't scale to the new situation where static and dynamic percpu > variables behave uniformly.
Well, I miss a bit of per cpu internals so I won't argue further :)
Thanks.
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