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rcu: Remove kfree_rcu() special casing and lazy-callback handling

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This commit removes kfree_rcu() special-casing and the lazy-callback
handling from Tree RCU.  It moves some of this special casing to Tiny RCU,
the removal of which will be the subject of later commits.

This results in a nice negative delta.

Suggested-by: Paul E. McKenney <paulmck@linux.ibm.com>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
[ paulmck: Add slab.h #include, thanks to kbuild test robot <lkp@intel.com>. ]
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Joel Fernandes (Google)
2019-08-30 12:36:32 -04:00
committed by Paul E. McKenney
parent e99637becb
commit 77a40f9703
12 changed files with 90 additions and 159 deletions
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27
kernel/rcu/rcu.h
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@@ -198,33 +198,6 @@ 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)
{
rcu_callback_t f;
unsigned long offset = (unsigned long)head->func;
rcu_lock_acquire(&rcu_callback_map);
if (__is_kfree_rcu_offset(offset)) {
trace_rcu_invoke_kfree_callback(rn, head, offset);
kfree((void *)head - offset);
rcu_lock_release(&rcu_callback_map);
return true;
} else {
trace_rcu_invoke_callback(rn, head);
f = head->func;
WRITE_ONCE(head->func, (rcu_callback_t)0L);
f(head);
rcu_lock_release(&rcu_callback_map);
return false;
}
}
#ifdef CONFIG_RCU_STALL_COMMON
extern int rcu_cpu_stall_ftrace_dump;