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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-27 13:17:02 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:38:18 -0700 |
| commit | 0f9be8cabbc343218dd2807af7308656be113045 (patch) | |
| tree | d99e786bc49f6d77bbd1fa4fa7c4df31de9fed8d /kernel/rcu/tree.h | |
| parent | 9577df9a3122af08fff84b8a1a60dccf524a3891 (diff) | |
| download | linux-0f9be8cabbc343218dd2807af7308656be113045.tar.bz2 | |
rcu: Eliminate flavor scan in rcu_momentary_dyntick_idle()
The rcu_momentary_dyntick_idle() function scans the RCU flavors, checking
that one of them still needs a quiescent state before doing an expensive
atomic operation on the ->dynticks counter. However, this check reduces
overhead only after a rare race condition, and increases complexity. This
commit therefore removes the scan and the mechanism enabling the scan.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 76e4467bc765..b212cd0f22c7 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -113,7 +113,7 @@ struct rcu_dynticks { /* Process level is worth LLONG_MAX/2. */ int dynticks_nmi_nesting; /* Track NMI nesting level. */ atomic_t dynticks; /* Even value for idle, else odd. */ - int rcu_sched_qs_mask; /* GP old, need heavy quiescent state. */ + bool rcu_need_heavy_qs; /* GP old, need heavy quiescent state. */ unsigned long rcu_qs_ctr; /* Light universal quiescent state ctr. */ #ifdef CONFIG_NO_HZ_FULL_SYSIDLE long long dynticks_idle_nesting; @@ -484,7 +484,6 @@ struct rcu_state { struct rcu_node *level[RCU_NUM_LVLS + 1]; /* Hierarchy levels (+1 to */ /* shut bogus gcc warning) */ - u8 flavor_mask; /* bit in flavor mask. */ struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */ call_rcu_func_t call; /* call_rcu() flavor. */ int ncpus; /* # CPUs seen so far. */ |