Merge branches 'doc.2012.10.23c', 'fixes.2012.10.23c', 'hotplug.2012.10.23c', 'srcu...

diff --cc Documentation/RCU/whatisRCU.txt
Simple merge

diff --cc kernel/rcutorture.c
Simple merge

diff --cc kernel/rcutree.c
index 74df86bd9204aef5ec9d14ca8b4b0094777bef87,ca3221595ed53475591d286de192bac718e98051,4eafb89bd60f2885f2f1e7b389d3758fa7611328,74df86bd9204aef5ec9d14ca8b4b0094777bef87,8ef81527a89f3641365529aef5ea8f20f75be40e..027153cfa1f44bf37d903a3050d582ee80dc9b06
--- 1/kernel/rcutree.c
--- 2/kernel/rcutree.c
--- 3/kernel/rcutree.c
--- 4/kernel/rcutree.c
--- 5/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@@@@@ -212,20 -212,20 -212,20 -212,20 -212,14 +212,14 @@@@@@ DEFINE_PER_CPU(struct rcu_dynticks, rcu
     #endif
     };
     
- ---static int blimit = 10;            /* Maximum callbacks per rcu_do_batch. */
- ---static int qhimark = 10000;        /* If this many pending, ignore blimit. */
- ---static int qlowmark = 100; /* Once only this many pending, use blimit. */
+ +++static long blimit = 10;   /* Maximum callbacks per rcu_do_batch. */
+ +++static long qhimark = 10000;       /* If this many pending, ignore blimit. */
+ +++static long qlowmark = 100;        /* Once only this many pending, use blimit. */
     
- ---module_param(blimit, int, 0444);
- ---module_param(qhimark, int, 0444);
- ---module_param(qlowmark, int, 0444);
- -- 
- -- int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
- -- int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
- -- 
- -- module_param(rcu_cpu_stall_suppress, int, 0644);
- -- module_param(rcu_cpu_stall_timeout, int, 0644);
+ +++module_param(blimit, long, 0444);
+ +++module_param(qhimark, long, 0444);
+ +++module_param(qlowmark, long, 0444);
     
 -   int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
 -   int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
 -   
 -   module_param(rcu_cpu_stall_suppress, int, 0644);
 -   module_param(rcu_cpu_stall_timeout, int, 0644);
 -   
     static ulong jiffies_till_first_fqs = RCU_JIFFIES_TILL_FORCE_QS;
     static ulong jiffies_till_next_fqs = RCU_JIFFIES_TILL_FORCE_QS;
     
@@@@@@ -2308,10 -2347,10 -2305,32 -2308,10 -2301,10 +2337,32 @@@@@@ static int synchronize_sched_expedited_
      */
     void synchronize_sched_expedited(void)
     {
-- --   int firstsnap, s, snap, trycount = 0;
++ ++   long firstsnap, s, snap;
++ ++   int trycount = 0;
++ ++   struct rcu_state *rsp = &rcu_sched_state;
+  + 
 -  -   /* Note that atomic_inc_return() implies full memory barrier. */
 -  -   firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started);
++ ++   /*
++ ++    * If we are in danger of counter wrap, just do synchronize_sched().
++ ++    * By allowing sync_sched_expedited_started to advance no more than
++ ++    * ULONG_MAX/8 ahead of sync_sched_expedited_done, we are ensuring
++ ++    * that more than 3.5 billion CPUs would be required to force a
++ ++    * counter wrap on a 32-bit system.  Quite a few more CPUs would of
++ ++    * course be required on a 64-bit system.
++ ++    */
++ ++   if (ULONG_CMP_GE((ulong)atomic_long_read(&rsp->expedited_start),
++ ++                    (ulong)atomic_long_read(&rsp->expedited_done) +
++ ++                    ULONG_MAX / 8)) {
++ ++           synchronize_sched();
++ ++           atomic_long_inc(&rsp->expedited_wrap);
++ ++           return;
++ ++   }
 +  +
-  -    /* Note that atomic_inc_return() implies full memory barrier. */
-  -    firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started);
++ ++   /*
++ ++    * Take a ticket.  Note that atomic_inc_return() implies a
++ ++    * full memory barrier.
++ ++    */
++ ++   snap = atomic_long_inc_return(&rsp->expedited_start);
++ ++   firstsnap = snap;
        get_online_cpus();
        WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id()));
     

diff --cc kernel/rcutree.h
Simple merge

diff --cc kernel/rcutree_plugin.h
Simple merge