--- /dev/null
+/*
+ * Read-Copy Update definitions shared among RCU implementations.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you can access it online at
+ * http://www.gnu.org/licenses/gpl-2.0.html.
+ *
+ * Copyright IBM Corporation, 2011
+ *
+ * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ */
+
+#ifndef __LINUX_RCU_H
+#define __LINUX_RCU_H
+
+#include <trace/events/rcu.h>
+#ifdef CONFIG_RCU_TRACE
+#define RCU_TRACE(stmt) stmt
+#else /* #ifdef CONFIG_RCU_TRACE */
+#define RCU_TRACE(stmt)
+#endif /* #else #ifdef CONFIG_RCU_TRACE */
+
+/*
+ * Process-level increment to ->dynticks_nesting field. This allows for
+ * architectures that use half-interrupts and half-exceptions from
+ * process context.
+ *
+ * DYNTICK_TASK_NEST_MASK defines a field of width DYNTICK_TASK_NEST_WIDTH
+ * that counts the number of process-based reasons why RCU cannot
+ * consider the corresponding CPU to be idle, and DYNTICK_TASK_NEST_VALUE
+ * is the value used to increment or decrement this field.
+ *
+ * The rest of the bits could in principle be used to count interrupts,
+ * but this would mean that a negative-one value in the interrupt
+ * field could incorrectly zero out the DYNTICK_TASK_NEST_MASK field.
+ * We therefore provide a two-bit guard field defined by DYNTICK_TASK_MASK
+ * that is set to DYNTICK_TASK_FLAG upon initial exit from idle.
+ * The DYNTICK_TASK_EXIT_IDLE value is thus the combined value used upon
+ * initial exit from idle.
+ */
+#define DYNTICK_TASK_NEST_WIDTH 7
+#define DYNTICK_TASK_NEST_VALUE ((LLONG_MAX >> DYNTICK_TASK_NEST_WIDTH) + 1)
+#define DYNTICK_TASK_NEST_MASK (LLONG_MAX - DYNTICK_TASK_NEST_VALUE + 1)
+#define DYNTICK_TASK_FLAG ((DYNTICK_TASK_NEST_VALUE / 8) * 2)
+#define DYNTICK_TASK_MASK ((DYNTICK_TASK_NEST_VALUE / 8) * 3)
+#define DYNTICK_TASK_EXIT_IDLE (DYNTICK_TASK_NEST_VALUE + \
+ DYNTICK_TASK_FLAG)
+
+/*
+ * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
+ * by call_rcu() and rcu callback execution, and are therefore not part of the
+ * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
+ */
+
+#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
+# define STATE_RCU_HEAD_READY 0
+# define STATE_RCU_HEAD_QUEUED 1
+
+extern struct debug_obj_descr rcuhead_debug_descr;
+
+static inline int debug_rcu_head_queue(struct rcu_head *head)
+{
+ int r1;
+
+ r1 = debug_object_activate(head, &rcuhead_debug_descr);
+ debug_object_active_state(head, &rcuhead_debug_descr,
+ STATE_RCU_HEAD_READY,
+ STATE_RCU_HEAD_QUEUED);
+ return r1;
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+ debug_object_active_state(head, &rcuhead_debug_descr,
+ STATE_RCU_HEAD_QUEUED,
+ STATE_RCU_HEAD_READY);
+ debug_object_deactivate(head, &rcuhead_debug_descr);
+}
+#else /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+static inline int debug_rcu_head_queue(struct rcu_head *head)
+{
+ return 0;
+}
+
+static inline void debug_rcu_head_unqueue(struct rcu_head *head)
+{
+}
+#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+
+void kfree(const void *);
+
+/*
+ * Reclaim the specified callback, either by invoking it (non-lazy case)
+ * or freeing it directly (lazy case). Return true if lazy, false otherwise.
+ */
+static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head)
+{
+ unsigned long offset = (unsigned long)head->func;
+
+ rcu_lock_acquire(&rcu_callback_map);
+ if (__is_kfree_rcu_offset(offset)) {
+ RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
+ kfree((void *)head - offset);
+ rcu_lock_release(&rcu_callback_map);
+ return true;
+ } else {
+ RCU_TRACE(trace_rcu_invoke_callback(rn, head));
+ head->func(head);
+ rcu_lock_release(&rcu_callback_map);
+ return false;
+ }
+}
+
+#ifdef CONFIG_RCU_STALL_COMMON
+
+extern int rcu_cpu_stall_suppress;
+int rcu_jiffies_till_stall_check(void);
+
+#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+
+/*
+ * Strings used in tracepoints need to be exported via the
+ * tracing system such that tools like perf and trace-cmd can
+ * translate the string address pointers to actual text.
+ */
+#define TPS(x) tracepoint_string(x)
+
+void rcu_early_boot_tests(void);
+
+/*
+ * This function really isn't for public consumption, but RCU is special in
+ * that context switches can allow the state machine to make progress.
+ */
+extern void resched_cpu(int cpu);
+
+#endif /* __LINUX_RCU_H */
Code Review / kvmfornfv.git / blobdiff