> From: Dan Magenheimer > Sent: Thursday, February 28, 2013 11:13 AM > To: Seth Jennings; Andrew Morton > Cc: Greg Kroah-Hartman; Nitin Gupta; Minchan Kim; Konrad Rzeszutek Wilk; Dan Magenheimer; Robert > Jennings; Jenifer Hopper; Mel Gorman; Johannes Weiner; Rik van Riel; Larry Woodman; Benjamin > Herrenschmidt; Dave Hansen; Joe Perches; Joonsoo Kim; Cody P Schafer; linux-mm@xxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; devel@xxxxxxxxxxxxxxxxxxxx > Subject: RE: [PATCHv6 4/8] zswap: add to mm/ > > > From: Seth Jennings [mailto:sjenning@xxxxxxxxxxxxxxxxxx] > > Subject: [PATCHv6 4/8] zswap: add to mm/ > > > > +/* > > + * Maximum compression ratio, as as percentage, for an acceptable > > + * compressed page. Any pages that do not compress by at least > > + * this ratio will be rejected. > > +*/ > > +static unsigned int zswap_max_compression_ratio = 80; > > +module_param_named(max_compression_ratio, > > + zswap_max_compression_ratio, uint, 0644); > > Unless this is a complete coincidence, I believe that > the default value "80" is actually: > > (100 * (1L >> ZS_MAX_ZSPAGE_ORDER)) / > ((1L >> ZS_MAX_ZSPAGE_ORDER)) + 1) Doh! If it wasn't obvious, those should be left shift operators, not right shift. So.... (100 * (1L << ZS_MAX_ZSPAGE_ORDER)) / ((1L << ZS_MAX_ZSPAGE_ORDER)) + 1) Sorry for that. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href