On Mon, Nov 28, 2011 at 03:45:53AM +0000, YAMAMOTO Takashi wrote: > hi, > > > On Sun, Nov 20, 2011 at 06:52:10PM +0000, YAMAMOTO Takashi wrote: > >> hi, > >> > >> i'd like to to either fix or remove O->A page loaning. > >> > >> the biggest problem is the lack of users. thus no way to test. > >> any ideas? > > > > some years ago I wrote some prototype code to use the O->A loaning for > > read() and write(). the read() side worked, I don't think I had tested > > the write() side so it probably has problems. the patch is still around: > > ftp://ftp.netbsd.org/pub/NetBSD/misc/chs/diff.uvm_readloan.8 > > > > it's quite a bit out of date, but I think most of the changes needed > > to update it would be mechanical. > > i'll take a look. thanks. > > did it (at least the read() side) have actual performance benefit > compared to dumb copying?
it helped quite a lot, yes. here's the email thread: http://mail-index.netbsd.org/tech-kern/2005/02/15/0021.html -Chuck