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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-01-27 23:17:50 +0100 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 20:38:18 +0200 |
| commit | 9226b10d78ffe7895549045fe388dc5e73b87eac (patch) | |
| tree | 29d959a37f8d502c97948e49f895ae3269793b12 /kernel/rcu/tree.h | |
| parent | rcu: Eliminate flavor scan in rcu_momentary_dyntick_idle() (diff) | |
| download | linux-9226b10d78ffe7895549045fe388dc5e73b87eac.tar.xz linux-9226b10d78ffe7895549045fe388dc5e73b87eac.zip | |
rcu: Place guard on rcu_all_qs() and rcu_note_context_switch() actions
The rcu_all_qs() and rcu_note_context_switch() do a series of checks,
taking various actions to supply RCU with quiescent states, depending
on the outcomes of the various checks. This is a bit much for scheduling
fastpaths, so this commit creates a separate ->rcu_urgent_qs field in
the rcu_dynticks structure that acts as a global guard for these checks.
Thus, in the common case, rcu_all_qs() and rcu_note_context_switch()
check the ->rcu_urgent_qs field, find it false, and simply return.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index b212cd0f22c7..d2f276fc2edc 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -113,8 +113,9 @@ 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. */ - bool rcu_need_heavy_qs; /* 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. */ + bool rcu_urgent_qs; /* GP old need light quiescent state. */ #ifdef CONFIG_NO_HZ_FULL_SYSIDLE long long dynticks_idle_nesting; /* irq/process nesting level from idle. */ |