rcu: Eliminate initialization-time use of rsp (eb7a6653) · Commits · 戴 / test

kernel/rcu/tree.c

+12 −13

Original line number	Diff line number	Diff line
		@@ -3455,7 +3455,6 @@ void rcu_cpu_starting(unsigned int cpu)
		unsigned long oldmask;
		struct rcu_data *rdp;
		struct rcu_node *rnp;
		struct rcu_state *rsp = &rcu_state;

		if (per_cpu(rcu_cpu_started, cpu))
		return;
		@@ -3472,10 +3471,10 @@ void rcu_cpu_starting(unsigned int cpu)
		oldmask ^= rnp->expmaskinitnext;
		nbits = bitmap_weight(&oldmask, BITS_PER_LONG);
		/* Allow lockless access for expedited grace periods. */
		smp_store_release(&rsp->ncpus, rsp->ncpus + nbits); /* ^^^ */
		smp_store_release(&rcu_state.ncpus, rcu_state.ncpus + nbits); /* ^^^ */
		rcu_gpnum_ovf(rnp, rdp); /* Offline-induced counter wrap? */
		rdp->rcu_onl_gp_seq = READ_ONCE(rsp->gp_seq);
		rdp->rcu_onl_gp_flags = READ_ONCE(rsp->gp_flags);
		rdp->rcu_onl_gp_seq = READ_ONCE(rcu_state.gp_seq);
		rdp->rcu_onl_gp_flags = READ_ONCE(rcu_state.gp_flags);
		if (rnp->qsmask & mask) { /* RCU waiting on incoming CPU? */
		/* Report QS -after- changing ->qsmaskinitnext! */
		rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
		@@ -3667,7 +3666,6 @@ static void __init rcu_init_one(void)
		int i;
		int j;
		struct rcu_node *rnp;
		struct rcu_state *rsp = &rcu_state;

		BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */

		@@ -3678,14 +3676,15 @@ static void __init rcu_init_one(void)
		/* Initialize the level-tracking arrays. */

		for (i = 1; i < rcu_num_lvls; i++)
		rsp->level[i] = rsp->level[i - 1] + num_rcu_lvl[i - 1];
		rcu_state.level[i] =
		rcu_state.level[i - 1] + num_rcu_lvl[i - 1];
		rcu_init_levelspread(levelspread, num_rcu_lvl);

		/* Initialize the elements themselves, starting from the leaves. */

		for (i = rcu_num_lvls - 1; i >= 0; i--) {
		cpustride *= levelspread[i];
		rnp = rsp->level[i];
		rnp = rcu_state.level[i];
		for (j = 0; j < num_rcu_lvl[i]; j++, rnp++) {
		raw_spin_lock_init(&ACCESS_PRIVATE(rnp, lock));
		lockdep_set_class_and_name(&ACCESS_PRIVATE(rnp, lock),
		@@ -3693,9 +3692,9 @@ static void __init rcu_init_one(void)
		raw_spin_lock_init(&rnp->fqslock);
		lockdep_set_class_and_name(&rnp->fqslock,
		&rcu_fqs_class[i], fqs[i]);
		rnp->gp_seq = rsp->gp_seq;
		rnp->gp_seq_needed = rsp->gp_seq;
		rnp->completedqs = rsp->gp_seq;
		rnp->gp_seq = rcu_state.gp_seq;
		rnp->gp_seq_needed = rcu_state.gp_seq;
		rnp->completedqs = rcu_state.gp_seq;
		rnp->qsmask = 0;
		rnp->qsmaskinit = 0;
		rnp->grplo = j * cpustride;
		@@ -3709,7 +3708,7 @@ static void __init rcu_init_one(void)
		} else {
		rnp->grpnum = j % levelspread[i - 1];
		rnp->grpmask = 1UL << rnp->grpnum;
		rnp->parent = rsp->level[i - 1] +
		rnp->parent = rcu_state.level[i - 1] +
		j / levelspread[i - 1];
		}
		rnp->level = i;
		@@ -3723,8 +3722,8 @@ static void __init rcu_init_one(void)
		}
		}

		init_swait_queue_head(&rsp->gp_wq);
		init_swait_queue_head(&rsp->expedited_wq);
		init_swait_queue_head(&rcu_state.gp_wq);
		init_swait_queue_head(&rcu_state.expedited_wq);
		rnp = rcu_first_leaf_node();
		for_each_possible_cpu(i) {
		while (i > rnp->grphi)

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