|Bill Allombert on Sat, 24 Sep 2016 11:38:29 +0200|
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|Re: Use PROT_NONE for unused virtual stack memory|
On Sat, Sep 24, 2016 at 08:33:28AM +0200, Jeroen Demeyer wrote: > Hello pari-dev, > > In attachment you find a patch to change the way how stack memory is > allocated with mmap(). It is meant to improve support for Linux with > vm.overcommit = 2  and still allow a reasonably large parisizemax in that > case. > > The idea is to use PROT_NONE for the unused part of the PARI stack (between > vbot and bot). Memory mmap()ed with PROT_NONE is not committed: it does not > count against the available physical/swap memory available for the system. > > One consequence of this patch is that increasing the actual size (during > some calculation which needs more stack space) can fail. This is not a > problem since we can handle this failure the same way that we handle a usual > PARI stack overflow. > > Otherwise, this does not functionally affect PARI. Thanks for your patch. Did you test this on OS X as well ? Cheers, Bill.