LU-3494 libcfs: Add relocation function to libcfs heap

When changing the values of the node in the heap which might affect
its ranking, we have to remove the node from the heap, change the
values and then insert the node into the heap again. The process of
inserting into the heap might fail because of memory insufficiency.
Sometimes, it is not convienient and efficient for a caller to handle
such kind of failure.

This patch adds a new function to do the job.

Signed-off-by: Li Xi <lixi@ddn.com>
Change-Id: I31ce530d750341f6479470ba61457d9ed03afed3
Reviewed-on: http://review.whamcloud.com/6743
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Bobbie Lind <bobbie.j.lind@intel.com>
Reviewed-by: Liang Zhen <liang.zhen@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/libcfs/include/libcfs/libcfs_heap.h b/libcfs/include/libcfs/libcfs_heap.h
index 40d4eda..8a9a855 100644 (file)
--- a/libcfs/include/libcfs/libcfs_heap.h
+++ b/libcfs/include/libcfs/libcfs_heap.h
@@ -166,6 +166,7 @@ cfs_binheap_t *cfs_binheap_create(cfs_binheap_ops_t *ops, unsigned int flags,
 cfs_binheap_node_t *cfs_binheap_find(cfs_binheap_t *h, unsigned int idx);
 int cfs_binheap_insert(cfs_binheap_t *h, cfs_binheap_node_t *e);
 void cfs_binheap_remove(cfs_binheap_t *h, cfs_binheap_node_t *e);
+void cfs_binheap_relocate(cfs_binheap_t *h, cfs_binheap_node_t *e);
 
 static inline int
 cfs_binheap_size(cfs_binheap_t *h)

diff --git a/libcfs/libcfs/heap.c b/libcfs/libcfs/heap.c
index f9362ea..ed87fa7 100644 (file)
--- a/libcfs/libcfs/heap.c
+++ b/libcfs/libcfs/heap.c
@@ -463,8 +463,7 @@ cfs_binheap_remove(cfs_binheap_t *h, cfs_binheap_node_t *e)
 
        last->chn_index = cur_idx;
        *cur_ptr = last;
-       if (!cfs_binheap_bubble(h, *cur_ptr))
-               cfs_binheap_sink(h, *cur_ptr);
+       cfs_binheap_relocate(h, *cur_ptr);
 
        e->chn_index = CBH_POISON;
        if (h->cbh_ops->hop_exit)
@@ -472,4 +471,19 @@ cfs_binheap_remove(cfs_binheap_t *h, cfs_binheap_node_t *e)
 }
 EXPORT_SYMBOL(cfs_binheap_remove);
 
+/**
+ * Relocate a node in the binary heap.
+ * Should be called whenever a node's values
+ * which affects its ranking are changed.
+ *
+ * \param[in] h The heap
+ * \param[in] e The node
+ */
+void
+cfs_binheap_relocate(cfs_binheap_t *h, cfs_binheap_node_t *e)
+{
+       if (!cfs_binheap_bubble(h, e))
+               cfs_binheap_sink(h, e);
+}
+EXPORT_SYMBOL(cfs_binheap_relocate);
 /** @} heap */