On Sun, Jun 24, 2018 at 12:34:51PM -0700, Joel Fernandes wrote: > From: "Joel Fernandes (Google)" <joel@xxxxxxxxxxxxxxxxx> > > The very useful RCU Data-Structures describes that the dynticks counter > of the rcu_dynticks data structure is incremented when we transitions to > or from dynticks-idle mode. However it doesn't mention that it is also > incremented due to transitions to and from user mode which for dynticks > purposes is an extended quiescent state. > > I found this with tracing calls to rcu_dynticks_eqs_enter which can also > happen from rcu_user_enter. Lets add this information to the > Data-Structures document. > > Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> Good addition, queued, thank you! Thanx, Paul > --- > .../RCU/Design/Data-Structures/Data-Structures.html | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html > index f5120a00f511..50be87e59937 100644 > --- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html > +++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html > @@ -1227,9 +1227,11 @@ to overflow the counter, this approach corrects the > CPU enters the idle loop from process context. > > </p><p>The <tt>->dynticks</tt> field counts the corresponding > -CPU's transitions to and from dyntick-idle mode, so that this counter > -has an even value when the CPU is in dyntick-idle mode and an odd > -value otherwise. > +CPU's transitions to and from either dyntick-idle or user mode, so > +that this counter has an even value when the CPU is in dyntick-idle > +mode or user mode and an odd value otherwise. The transitions to/from > +user mode need to be counted for user mode adaptive-ticks support > +(see timers/NO_HZ.txt). > > </p><p>The <tt>->rcu_need_heavy_qs</tt> field is used > to record the fact that the RCU core code would really like to > -- > 2.18.0.rc2.346.g013aa6912e-goog > -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
