Design/Data-Structures/Data-Structures.rst

272      1   unsigned long gp_seq;
274 RCU grace periods are numbered, and the ``->gp_seq`` field contains the
278 ``->gp_seq`` are zero, then RCU is idle. Any other value in the bottom
282 There are ``->gp_seq`` fields in the ``rcu_node`` and ``rcu_data``
292 | Given that the root rcu_node structure has a gp_seq field,            |
293 | why does RCU maintain a separate gp_seq in the rcu_state structure?   |
294 | Why not just use the root rcu_node's gp_seq as the official record    |
300 | updating the root node's gp_seq immediately would create unnecessary  |
303 | If we did rcu_seq_start() directly on the root node's gp_seq:         |
305 | 1. All CPUs would immediately see their node's gp_seq from their rdp's|
306 |    gp_seq, in rcu_pending(). They would all then invoke the RCU-core. |
311 |    needs to report quiescent state (no qsmask), update rdp->gp_seq,   |
315 | By having a separate rcu_state.gp_seq, we can increment the official  |
318 | updates the root node's gp_seq and qsmask together under the same lock|
416      1   unsigned long gp_seq;
419 The ``rcu_node`` structures' ``->gp_seq`` fields are the counterparts of
422 two bits of a given ``rcu_node`` structure's ``->gp_seq`` field is zero,
425 The ``>gp_seq`` field of each ``rcu_node`` structure is updated at the
430 request is considered fulfilled when the value of the ``->gp_seq`` field
437 | very long time. Won't wrapping of the ``->gp_seq`` field cause        |
443 | ``->gp_seq`` field, the ``->gp_seq_needed`` field will be updated at  |
512 | ``->gp_seq``.                                                         |
717    10   unsigned long gp_seq[RCU_CBLIST_NSEGS];
728    grace period is current, hence the ``->gp_seq`` field.
775 The ``->gp_seq[]`` array records grace-period numbers corresponding to
862      1   unsigned long gp_seq;
868 The ``->gp_seq`` field is the counterpart of the field of the same name
876 structure's ``->gp_seq`` are zero, then this ``rcu_data`` structure
901 idle for so long that the ``gp_seq`` counter is in danger of overflow,
932 of its ``rcu_data`` structure's ``->gp_seq`` field differs from that of
934 structure's ``->gp_seq`` field is updated at the beginnings and ends of