Messages in this thread | | | Date | Sat, 5 Dec 2015 17:56:56 -0800 | From | Josh Triplett <> | Subject | Re: [PATCH tip/core/rcu 6/8] rcutorture: Print symbolic name for ->gp_state |
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On Sat, Dec 05, 2015 at 05:54:36PM -0800, Paul E. McKenney wrote: > On Fri, Dec 04, 2015 at 05:04:21PM -0800, Josh Triplett wrote: > > On Fri, Dec 04, 2015 at 04:23:50PM -0800, Paul E. McKenney wrote: > > > Currently, ->gp_state is printed as an integer, which slows debugging. > > > This commit therefore prints a symbolic name in addition to the integer. > > > > > > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > > > [ Updated to fix relational operator called out by Dan Carpenter. ] > > > --- > > > kernel/rcu/tree.c | 15 +++++++++++++-- > > > kernel/rcu/tree.h | 9 +++++++++ > > > 2 files changed, 22 insertions(+), 2 deletions(-) > > > > > > diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c > > > index 7b78c88e19a3..491c99a73996 100644 > > > --- a/kernel/rcu/tree.c > > > +++ b/kernel/rcu/tree.c > > > @@ -1187,6 +1187,16 @@ static void record_gp_stall_check_time(struct rcu_state *rsp) > > > } > > > > > > /* > > > + * Convert a ->gp_state value to a character string. > > > + */ > > > +static char *gp_state_getname(short gs) > > > > Same comment about "const char *" > > Good point, fixed! > > > > +{ > > > + if (gs < 0 || gs >= ARRAY_SIZE(gp_state_names)) > > > + return "???"; > > > + return gp_state_names[gs]; > > > +} > > > + > > > +/* > > > * Complain about starvation of grace-period kthread. > > > */ > > > static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) > > > @@ -1197,10 +1207,11 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp) > > > j = jiffies; > > > gpa = READ_ONCE(rsp->gp_activity); > > > if (j - gpa > 2 * HZ) { > > > - pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x s%d ->state=%#lx\n", > > > + pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx\n", > > > rsp->name, j - gpa, > > > rsp->gpnum, rsp->completed, > > > - rsp->gp_flags, rsp->gp_state, > > > + rsp->gp_flags, > > > + gp_state_getname(rsp->gp_state), rsp->gp_state, > > > rsp->gp_kthread ? rsp->gp_kthread->state : ~0); > > > if (rsp->gp_kthread) > > > sched_show_task(rsp->gp_kthread); > > > diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h > > > index f32bebb6bc90..f0304988e3f8 100644 > > > --- a/kernel/rcu/tree.h > > > +++ b/kernel/rcu/tree.h > > > @@ -544,6 +544,15 @@ struct rcu_state { > > > #define RCU_GP_DOING_FQS 4 /* Wait done for force-quiescent-state time. */ > > > #define RCU_GP_CLEANUP 5 /* Grace-period cleanup started. */ > > > #define RCU_GP_CLEANED 6 /* Grace-period cleanup complete. */ > > > +static char * const gp_state_names[] = { > > > > Same comment about "const char * const", but also, should this really go > > in a header file? Do any circumstances exist where this header could > > get included in more than one source file in a given build? If so, > > multiple copies of this array could potentially end up in the binary, if > > the compiler fails to merge them. > > I added the const. > > However, I left the array in the .h file. The issue is that the #defines > really have to be in the tree.h file. Given that, if I move the array > elsewhere, they will very likely drift out of sync. So this sounds like > a job for the compiler/linker... > > Ah, but there is another approach. It turns out that tree.h in included > only from tree.c and tree_trace.c. And tree_trace.c defines a CPP symbol > RCU_TREE_NONCORE that is used elsewhere in tree.h to keep tree_trace.c's > mitts off a number of attractive but dangerous functions. So I just put > the array under "#ifndef RCU_TREE_NONCORE". > > Fair enough?
Fair enough.
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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