[PATCH] i82593.h: make header comment GPL-compatible

[linux-2.6] / kernel / rcupdate.c

diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index f436993bd590a4b0bb145d4402d52cb2aaeb7c76..c4d159a21e042cc184a6d04e64b7b2273dfb5872 100644 (file)
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -45,6 +45,7 @@
 #include <linux/percpu.h>
 #include <linux/notifier.h>
 #include <linux/rcupdate.h>
+#include <linux/rcuref.h>
 #include <linux/cpu.h>
 
 /* Definition for rcupdate control block. */
@@ -70,7 +71,20 @@ DEFINE_PER_CPU(struct rcu_data, rcu_bh_data) = { 0L };
 
 /* Fake initialization required by compiler */
 static DEFINE_PER_CPU(struct tasklet_struct, rcu_tasklet) = {NULL};
-static int maxbatch = 10;
+static int maxbatch = 10000;
+
+#ifndef __HAVE_ARCH_CMPXCHG
+/*
+ * We use an array of spinlocks for the rcurefs -- similar to ones in sparc
+ * 32 bit atomic_t implementations, and a hash function similar to that
+ * for our refcounting needs.
+ * Can't help multiprocessors which donot have cmpxchg :(
+ */
+
+spinlock_t __rcuref_hash[RCUREF_HASH_SIZE] = {
+       [0 ... (RCUREF_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
+};
+#endif
 
 /**
  * call_rcu - Queue an RCU callback for invocation after a grace period.
@@ -95,6 +109,10 @@ void fastcall call_rcu(struct rcu_head *head,
        rdp = &__get_cpu_var(rcu_data);
        *rdp->nxttail = head;
        rdp->nxttail = &head->next;
+
+       if (unlikely(++rdp->count > 10000))
+               set_need_resched();
+
        local_irq_restore(flags);
 }
 
@@ -126,9 +144,24 @@ void fastcall call_rcu_bh(struct rcu_head *head,
        rdp = &__get_cpu_var(rcu_bh_data);
        *rdp->nxttail = head;
        rdp->nxttail = &head->next;
+       rdp->count++;
+/*
+ *  Should we directly call rcu_do_batch() here ?
+ *  if (unlikely(rdp->count > 10000))
+ *      rcu_do_batch(rdp);
+ */
        local_irq_restore(flags);
 }
 
+/*
+ * Return the number of RCU batches processed thus far.  Useful
+ * for debug and statistics.
+ */
+long rcu_batches_completed(void)
+{
+       return rcu_ctrlblk.completed;
+}
+
 /*
  * Invoke the completed RCU callbacks. They are expected to be in
  * a per-cpu list.
@@ -143,6 +176,7 @@ static void rcu_do_batch(struct rcu_data *rdp)
                next = rdp->donelist = list->next;
                list->func(list);
                list = next;
+               rdp->count--;
                if (++count >= maxbatch)
                        break;
        }
@@ -476,6 +510,7 @@ void synchronize_kernel(void)
 }
 
 module_param(maxbatch, int, 0);
+EXPORT_SYMBOL_GPL(rcu_batches_completed);
 EXPORT_SYMBOL(call_rcu);  /* WARNING: GPL-only in April 2006. */
 EXPORT_SYMBOL(call_rcu_bh);  /* WARNING: GPL-only in April 2006. */
 EXPORT_SYMBOL_GPL(synchronize_rcu);