2013/1/14 Mike Hommey <m...@glandium.org> > On Mon, Jan 14, 2013 at 11:09:07AM -0500, Benoit Jacob wrote: > > 2013/1/14 Mike Hommey <m...@glandium.org> > > > > > On Mon, Jan 14, 2013 at 11:43:44AM +1300, Robert O'Callahan wrote: > > > > I need a big read-only buffer full of zeroes. On Linux I could mmap > > > > /dev/zero read-only, and something similar on Windows/Mac I'm sure, > but > > > do > > > > we already have code for that, or better yet something like that > already > > > > mapped into memory? > > > > > > You could just use calloc(). Jemalloc will do the appropriate thing. > > > > > > > Out of curiosity, how can it? Since the block returned by calloc is not > > read-only, how would a subsequent non-zero write be handled? > > It doesn't set it as read-only, so that depends if roc really needs the > buffer to be read-only or not. >
I tried to ask a different question: Roc wants (IIUC) to allocate dummy zero pages that don't actually consume memory. You propose (IIUC) that he use calloc() for that. My question, then, is: how could calloc() avoid actually allocating real memory pages? If calloc() could know that these pages won't be written do, it could map dummy zero pages, but AFAICS it can't know that... Benoit > > Mike > _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
