----- On Apr 7, 2019, at 3:32 PM, Joel Fernandes, Google j...@joelfernandes.org wrote:
> On Sun, Apr 07, 2019 at 03:26:16PM -0400, Mathieu Desnoyers wrote: >> ----- On Apr 7, 2019, at 9:59 AM, paulmck paul...@linux.ibm.com wrote: >> >> > On Sun, Apr 07, 2019 at 06:39:41AM -0700, Paul E. McKenney wrote: >> >> On Sat, Apr 06, 2019 at 07:06:13PM -0400, Joel Fernandes wrote: >> > >> > [ . . . ] >> > >> >> > > diff --git a/include/asm-generic/vmlinux.lds.h >> >> > > b/include/asm-generic/vmlinux.lds.h >> >> > > index f8f6f04c4453..c2d919a1566e 100644 >> >> > > --- a/include/asm-generic/vmlinux.lds.h >> >> > > +++ b/include/asm-generic/vmlinux.lds.h >> >> > > @@ -338,6 +338,10 @@ >> >> > > KEEP(*(__tracepoints_ptrs)) /* Tracepoints: pointer >> >> > > array */ \ >> >> > > __stop___tracepoints_ptrs = .; >> >> > > \ >> >> > > *(__tracepoints_strings)/* Tracepoints: strings */ >> >> > > \ >> >> > > + . = ALIGN(8); >> >> > > \ >> >> > > + __start___srcu_struct = .; >> >> > > \ >> >> > > + *(___srcu_struct_ptrs) >> >> > > \ >> >> > > + __end___srcu_struct = .; >> >> > > \ >> >> > > } >> >> > > \ >> >> > >> >> > This vmlinux linker modification is not needed. I tested without it and >> >> > srcu >> >> > torture works fine with rcutorture built as a module. Putting further >> >> > prints >> >> > in kernel/module.c verified that the kernel is able to find the srcu >> >> > structs >> >> > just fine. You could squash the below patch into this one or apply it >> >> > on top >> >> > of the dev branch. >> >> >> >> Good point, given that otherwise FORTRAN named common blocks would not >> >> work. >> >> >> >> But isn't one advantage of leaving that stuff in the RO_DATA_SECTION() >> >> macro that it can be mapped read-only? Or am I suffering from excessive >> >> optimism? >> > >> > And to answer the other question, in the case where I am suffering from >> > excessive optimism, it should be a separate commit. Please see below >> > for the updated original commit thus far. >> > >> > And may I have your Tested-by? >> >> Just to confirm: does the cleanup performed in the modules going >> notifier end up acting as a barrier first before freeing the memory ? >> If not, is it explicitly stated that a barrier must be issued before >> module unload ? >> > > You mean rcu_barrier? It is mentioned in the documentation that this is the > responsibility of the module writer to prevent delays for all modules. It's a srcu barrier yes. Considering it would be a barrier specific to the srcu domain within that module, I don't see how it would cause delays for "all" modules if we implicitly issue the barrier on module unload. What am I missing ? Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
