On Tue, Jul 30, 2013 at 10:02:01AM +0200, Stephane Eranian wrote: > > Ahh. We don't put the useful bits in the mmap event; we'll need to fix > > that too then ;-) > > > > Doing so is going to be a bit of a bother since we use the tail of > > PERF_RECORD_MMAP for filenames and thus aren't particularly extensible. > > > > This would mean doing something like PERF_RECORD_MMAP2 and some means > > for userspace to requrest the new events instead of the old one. > > > Tracking mmaps even for shmat() won't cover the paging cases. When you page a > page back in, it most likely gets a different physical page. How would > we track that > case too using the same approach?
It doesn't matter. Even if a page ends up being a different physical page, it will always be the same sb:inode:pgoffset. You should be able to always uniquely identify a (shared) page by that triplet. So if we create a net MMAP record that includes the device (substitute for the superblock) and inode information we should be good. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
