On Wed, Oct 04, 2017 at 08:50:49AM +0200, Laurent Dufour wrote: > On 25/09/2017 18:27, Alexei Starovoitov wrote: > > On Mon, Sep 18, 2017 at 12:15 AM, Laurent Dufour > > <ldufour@xxxxxxxxxxxxxxxxxx> wrote: > >> Despite the unprovable lockdep warning raised by Sergey, I didn't get any > >> feedback on this series. > >> > >> Is there a chance to get it moved upstream ? > > > > what is the status ? > > We're eagerly looking forward for this set to land, > > since we have several use cases for tracing that > > will build on top of this set as discussed at Plumbers. > > Hi Alexei, > > Based on Plumber's note [1], it sounds that the use case is tied to the BPF > tracing where a call tp find_vma() call will be made on a process's context > to fetch user space's symbols. > > Am I right ? > Is the find_vma() call made in the context of the process owning the mm > struct ? Hi Laurent, we're thinking about several use cases on top of your work. First one is translation of user address to file_handle where we need to do find_vma() from preempt_disabled context of bpf program. My understanding that srcu should solve that nicely. Second is making probe_read() to try harder when address is causing minor fault. We're thinking that find_vma() followed by some new light weight filemap_access() that doesn't sleep will do the trick. In both cases the program will be accessing current->mm -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
