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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-06-23 02:06:26 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-09-23 16:41:54 +0200 |
| commit | 4cdfc175c25c89eedc08460b5e6239c2ec67fcb6 (patch) | |
| tree | 716acd208cb0633cdd19fc0cd5ad601906cceb24 /kernel/rcutree.h | |
| parent | rcu: Segregate rcu_state fields to improve cache locality (diff) | |
| download | linux-4cdfc175c25c89eedc08460b5e6239c2ec67fcb6.tar.xz linux-4cdfc175c25c89eedc08460b5e6239c2ec67fcb6.zip | |
rcu: Move quiescent-state forcing into kthread
As the first step towards allowing quiescent-state forcing to be
preemptible, this commit moves RCU quiescent-state forcing into the
same kthread that is now used to initialize and clean up after grace
periods. This is yet another step towards keeping scheduling
latency down to a dull roar.
Updated to change from raw_spin_lock_irqsave() to raw_spin_lock_irq()
and to remove the now-unused rcu_state structure fields as suggested by
Peter Zijlstra.
Reported-by: Mike Galbraith <mgalbraith@suse.de>
Reported-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree.h')
| -rw-r--r-- | kernel/rcutree.h | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/kernel/rcutree.h b/kernel/rcutree.h index 5d92b80a0a28..2d04106d1533 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -378,13 +378,6 @@ struct rcu_state { u8 fqs_state ____cacheline_internodealigned_in_smp; /* Force QS state. */ - u8 fqs_active; /* force_quiescent_state() */ - /* is running. */ - u8 fqs_need_gp; /* A CPU was prevented from */ - /* starting a new grace */ - /* period because */ - /* force_quiescent_state() */ - /* was running. */ u8 boost; /* Subject to priority boost. */ unsigned long gpnum; /* Current gp number. */ unsigned long completed; /* # of last completed gp. */ @@ -413,8 +406,6 @@ struct rcu_state { struct completion barrier_completion; /* Wake at barrier end. */ unsigned long n_barrier_done; /* ++ at start and end of */ /* _rcu_barrier(). */ - raw_spinlock_t fqslock; /* Only one task forcing */ - /* quiescent states. */ unsigned long jiffies_force_qs; /* Time at which to invoke */ /* force_quiescent_state(). */ unsigned long n_force_qs; /* Number of calls to */ @@ -433,6 +424,10 @@ struct rcu_state { struct list_head flavors; /* List of RCU flavors. */ }; +/* Values for rcu_state structure's gp_flags field. */ +#define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ +#define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ + extern struct list_head rcu_struct_flavors; #define for_each_rcu_flavor(rsp) \ list_for_each_entry((rsp), &rcu_struct_flavors, flavors) |