Heap allocation in the RTS

[David Feuer]

I'm not sure I understand. Are you saying allocateMightFail ignores the
usual nursery size? That's not my intention. It would actually be just fine
to simply fail if GC would be required--I can then back off, fail out to
CMM, trigger a GC there, and retry. Or I could perform an extra heap check
before I start; that's a little silly, but I doubt it'll be expensive
enough to really matter here.

On Thu, Sep 20, 2018, 5:42 AM Ömer Sinan Ağacan <omeragacan at gmail.com>
wrote:

> allocateMightFail allocates new nursery blocks as long as you don't hit the
> heap limit, so it returns NULL less often than you might think. In
> particular,
> it doesn't return NULL when the nursery is full, instead it allocates a new
> block and adds it to the nursery.
>
> I'd do the GC triggering part in Cmm code instead of C code -- I'm not
> sure if
> it's possible to do this in C code. There should be some functions in
> PrimOps.cmm that do heap allocation, maybe look there. I'd look for uses of
> ALLOC_PRIM. The file HeapStackCheck.cmm may also be helpful (may at least
> give
> an idea of how a GC is triggered).
>
> Ömer
>
> David Feuer <david.feuer at gmail.com>, 20 Eyl 2018 Per, 12:34 tarihinde
> şunu yazdı:
> >
> > If it returns NULL, then I need to back off what I'm doing and trigger a
> GC. How do I do the latter?
> >
> > On Thu, Sep 20, 2018, 5:31 AM Ömer Sinan Ağacan <omeragacan at gmail.com>
> wrote:
> >>
> >> allocateMightFail does the heap check for you and returns NULL. For the
> current
> >> capability you can use MyCapability() in Cmm and pass the value to the
> RTS
> >> function you're implementing.
> >>
> >> Ömer
> >>
> >> David Feuer <david.feuer at gmail.com>, 20 Eyl 2018 Per, 12:26 tarihinde
> >> şunu yazdı:
> >> >
> >> > Aha! Okay. How do I get the current capability to pass to that? I
> guess I should probably perform a heap check before calling lookupSta
> bleName for simplicity, at least to start.
> >> >
> >> > On Thu, Sep 20, 2018, 5:16 AM Ömer Sinan Ağacan <omeragacan at gmail.com>
> wrote:
> >> >>
> >> >> Have you seen Storage.c:allocateMightFail ?
> >> >>
> >> >> Ömer
> >> >>
> >> >>
> >> >> David Feuer <david.feuer at gmail.com>, 20 Eyl 2018 Per, 11:32
> tarihinde
> >> >> şunu yazdı:
> >> >> >
> >> >> > I'm working on re-implementing the stable name system. For the new
> design, it seems much cleaner to allocate stable names in lookupStableName
> (in rts/StableName.c) rather than in the C-- code that calls it. But I
> haven't seen RTS code that does heap allocation. Is it possible? If so, how
> do I do it?
> >> >> > _______________________________________________
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>
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