On Thu, 31 Jan 2008 11:10:13 +0100 Peter Zijlstra <[EMAIL PROTECTED]> wrote:
> > On Thu, 2008-01-31 at 02:05 -0800, Andrew Morton wrote: > > On Thu, 31 Jan 2008 10:53:26 +0100 Peter Zijlstra <[EMAIL PROTECTED]> wrote: > > > > > > > > On Thu, 2008-01-31 at 01:47 -0800, Andrew Morton wrote: > > > > On Thu, 31 Jan 2008 10:35:18 +0100 Peter Zijlstra <[EMAIL PROTECTED]> > > > > wrote: > > > > > > > > > > > > > > On Thu, 2008-01-31 at 01:12 -0800, Andrew Morton wrote: > > > > > > > > > > > Implementation-wise: make_pages_present() _can_ be converted to do > > > > > > this. > > > > > > But it's a lot of patching, and the result will be a cleaner, > > > > > > faster and > > > > > > smaller core MM. Whereas your approach is easy, but adds more code > > > > > > and > > > > > > leaves the old stuff slow-and-dirty. > > > > > > > > > > > > Guess which approach is preferred? ;) > > > > > > > > > > Ok, I'll look at using make_pages_present(). > > > > > > > > Am still curious to know what inspired this change. What are the use > > > > cases? Performance testing results, etc? > > > > > > Ah, that is Lennarts Pulse Audio thing, he has samples in memory which > > > might not have been used for a while, and he wants to be able to > > > pre-fetch those when he suspects they might need to be played. So that > > > once the audio thread comes along and stuffs them down /dev/dsp its all > > > nice in memory. > > > > > > Since its all soft real-time at best he feels its better to do a best > > > effort at not hitting swap than it is to strain the system with mlock > > > usage. > > > > hrm. Does he know about pthread_create()? > > I'm very sure he does. So you're suggesting to just create a thread and > touch that memory and be done with it? > > Lennart? That would get him out of trouble. But it certainly makes _sense_ for the kernel to implement MADV_WILLNEED for anon memory. From a consistency POV. But I don't know that the usefulness of the feature is worth actually expending code on. Heck, after five-odd years I'm still asking every second person I meet "why don't you use fadvise()?" (Reponse: ooooh!) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
