Sorry for deleting CC'd addresses. yahoo was whining... --- On Wed, 5/19/10, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Subject: Re: Unexpected splice "always copy" behavior observed > To: "Steven Rostedt" <rostedt@xxxxxxxxxxx> > Cc: "Nick Piggin" <npiggin@xxxxxxx>, "Mathieu Desnoyers" <mathieu.desnoyers@xxxxxxxxxxxx>, "Peter Zijlstra" <peterz@xxxxxxxxxxxxx>, "Frederic Weisbecker" <fweisbec@xxxxxxxxx>, "Pierre Tardy" <tardyp@xxxxxxxxx>, "Ingo Molnar" <mingo@xxxxxxx>, "Arnaldo Carvalho de Melo" <acme@xxxxxxxxxx>, "Tom Zanussi" <tzanussi@xxxxxxxxx>, "Paul Mackerras" <paulus@xxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, arjan@xxxxxxxxxxxxx, ziga.mahkovec@xxxxxxxxx, "davem" <davem@xxxxxxxxxxxxx>, linux-mm@xxxxxxxxx, "Andrew Morton" <akpm@xxxxxxxxxxxxxxxxxxxx>, "KOSAKI Motohiro" <kosaki.motohiro@xxxxxxxxxxxxxx>, "Christoph Lameter" <cl@xxxxxxxxxxxxxxxxxxxx>, "Tejun Heo" <tj@xxxxxxxxxx>, "Jens Axboe" <jens.axboe@xxxxxxxxxx> > Date: Wednesday, May 19, 2010, 2:59 PM > > > On Wed, 19 May 2010, Steven Rostedt wrote: > > > On Wed, 2010-05-19 at 07:39 -0700, Linus Torvalds > wrote: > > > > > The real limitation is likely always going to be > the fact that it has to > > > be page-aligned and a full page. For a lot of > splice inputs, that simply > > > won't be the case, and you'll end up copying for > alignment reasons anyway. > > > > That's understandable. For the use cases of splice I > use, I work to make > > it page aligned and full pages. Anyone else using > splice for > > optimizations, should do the same. It only makes > sense. > > > > The end of buffer may not be a full page, but then > it's the end anyway, > > and I'm not as interested in the speed. > > Btw, since you apparently have a real case - is the "splice > to file" > always just an append? IOW, if I'm not right in assuming > that the only > sane thing people would reasonable care about is "append to > a file", then > holler now. > I've a similar 'append' use case: http://marc.info/?l=linux-kernel&m=127143736527459&w=4 My mmapped buffers are pinned down. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>