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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2013-02-11 05:48:58 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-03-26 16:04:44 +0100 |
| commit | dae6e64d2bcfd4b06304ab864c7e3a4f6b5fedf4 (patch) | |
| tree | 79172d32aab5e0cecf8fc7ab4cf1fabf14328d81 /kernel/rcutree.c | |
| parent | rcu: Provide compile-time control for no-CBs CPUs (diff) | |
| download | linux-dae6e64d2bcfd4b06304ab864c7e3a4f6b5fedf4.tar.xz linux-dae6e64d2bcfd4b06304ab864c7e3a4f6b5fedf4.zip | |
rcu: Introduce proper blocking to no-CBs kthreads GP waits
Currently, the no-CBs kthreads do repeated timed waits for grace periods
to elapse. This is crude and energy inefficient, so this commit allows
no-CBs kthreads to specify exactly which grace period they are waiting
for and also allows them to block for the entire duration until the
desired grace period completes.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 6ad0716e65dc..433f426c848f 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -310,7 +310,7 @@ cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp) if (rcu_gp_in_progress(rsp)) return 0; /* No, a grace period is already in progress. */ - if (rcu_nocb_needs_gp(rdp)) + if (rcu_nocb_needs_gp(rsp)) return 1; /* Yes, a no-CBs CPU needs one. */ if (!rdp->nxttail[RCU_NEXT_TAIL]) return 0; /* No, this is a no-CBs (or offline) CPU. */ @@ -1364,6 +1364,7 @@ int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in) static void rcu_gp_cleanup(struct rcu_state *rsp) { unsigned long gp_duration; + int nocb = 0; struct rcu_data *rdp; struct rcu_node *rnp = rcu_get_root(rsp); @@ -1394,11 +1395,13 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) rcu_for_each_node_breadth_first(rsp, rnp) { raw_spin_lock_irq(&rnp->lock); rnp->completed = rsp->gpnum; + nocb += rcu_nocb_gp_cleanup(rsp, rnp); raw_spin_unlock_irq(&rnp->lock); cond_resched(); } rnp = rcu_get_root(rsp); raw_spin_lock_irq(&rnp->lock); + rcu_nocb_gp_set(rnp, nocb); rsp->completed = rsp->gpnum; /* Declare grace period done. */ trace_rcu_grace_period(rsp->name, rsp->completed, "end"); @@ -3084,6 +3087,7 @@ static void __init rcu_init_one(struct rcu_state *rsp, } rnp->level = i; INIT_LIST_HEAD(&rnp->blkd_tasks); + rcu_init_one_nocb(rnp); } } |