diff options
| 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 /Documentation/RCU | |
| parent | rcu: Pull rcu_qs_ctr into rcu_dynticks structure (diff) | |
| download | linux-dev-0f9be8cabbc343218dd2807af7308656be113045.tar.xz linux-dev-0f9be8cabbc343218dd2807af7308656be113045.zip | |
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 'Documentation/RCU')
| -rw-r--r-- | Documentation/RCU/Design/Data-Structures/Data-Structures.html | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/RCU/Design/Data-Structures/Data-Structures.html b/Documentation/RCU/Design/Data-Structures/Data-Structures.html index 3d0311657533..e4bf20a68fa3 100644 --- a/Documentation/RCU/Design/Data-Structures/Data-Structures.html +++ b/Documentation/RCU/Design/Data-Structures/Data-Structures.html @@ -1104,7 +1104,7 @@ Its fields are as follows: 1 int dynticks_nesting; 2 int dynticks_nmi_nesting; 3 atomic_t dynticks; - 4 int rcu_sched_qs_mask; + 4 bool rcu_need_heavy_qs; 5 unsigned long rcu_qs_ctr; </pre> @@ -1124,7 +1124,7 @@ 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. -</p><p>The <tt>->rcu_sched_qs_mask</tt> field is used +</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 see a quiescent state from the corresponding CPU, so much so that it is willing to call for heavy-weight dyntick-counter operations. |