On Tue, Nov 12, 2013 at 10:11:21PM +0100, Ingo Molnar wrote: > > * David Ahern <[email protected]> wrote: > > > > Dunno.. it _should_ all work. Try it and see what it does.. Once the > > > events are bigger than a page things might get 'interesting' though. > > Which could be the case with call-graph recording, right?
Not typically, I think we're limiting call graphs to 127 u64, which is ~1k. Maybe you can blow the single page if you also do a large top-of-stack copy for dwarf/unwind nonsense. > > one option here is not allow page faults and system wide system calls. > > system wide tracing needs mmap; page faults for a task can use write(). > > I left that option in case something like this came up. > > So maybe splice() sounds like the right long term solution after all? :-/ Right until you put a tracepoint (kprobe) somewhere in whatever function is used to transfer a single page into/from a splice pipe. You can always screw yourself over using this stuff, no exceptions. -- 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/
