Re: [PATCH] Use MAP_HUGETLB where supported (v3)

On 2013-11-21 18:09:38 -0300, Alvaro Herrera wrote:
> Abhijit Menon-Sen wrote:
> > At 2013-11-15 15:17:32 +0200, hlinnakangas@vmware.com wrote:
> 
> > > But I'm not wedded to the idea if someone objects; a log message might
> > > also be reasonable: "LOG: huge TLB pages are not supported on this
> > > platform, but huge_tlb_pages was 'on'"
> > 
> > Put that way, I have to wonder if the right thing to do is just to have
> > a "try_huge_pages=on|off" setting, and log a warning if the attempt did
> > not succeed. It would be easier to document, and I don't think there's
> > much point in making it an error if the allocation fails.
> 
> What about
> huge_tlb_pages={off,try}
> 
> Or maybe
> huge_tlb_pages={off,try,require}

I'd certainly want a setting that errors out if it cannot get the memory
using hugetables. If you rely on the reduction in memory (which can be
significant on large s_b, large max_connections), it's rather annoying
not to know whether it suceeded using it.

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
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