Re: [HACKERS] mmap and MAP_ANON

>
> Bruce Momjian wrote:
> >
> > Would people tell me what platforms do NOT support the MAP_ANON flag to
> > the mmap() system call?  You should find it in the mmap() manual page.
> >
> > *BSD has it, but I am not sure of the others.  I am researching cache
> > size issues and the use of mmap vs. SYSV shared memory.
>
> Well, I haven't noticed this discussion. However, I can't understand one
> thing:
>
> Why a lot of people investigate how to replace shared memory with
> mmapping anonymously but there is no discussion on replacing
> reads/writes with memory mapping of heap files.
>
> This way we would save not only on having better system cache
> utilisation but also we would have less memory copying. For me it seems
> like a more robust solution. I suggested it few months ago.
>
> If it's a bad idea, I wonder why?
> Are there any systems that cannot do mmaps at all?

mmap'ing a file is not necessary faster.  I will post time timings soon
that show this is not the case.

--
Bruce Momjian                          |  830 Blythe Avenue
maillist@candle.pha.pa.us              |  Drexel Hill, Pennsylvania 19026
  +  If your life is a hard drive,     |  (610) 353-9879(w)
  +  Christ can be your backup.        |  (610) 853-3000(h)