[UNIKRAFT PATCH v5 5/5] lib/ukallocpool: Batched allocation

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Introduce low-overhead interfaces for batched allocations and batched
freeing of objects.

Signed-off-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>
---
 lib/ukallocpool/exportsyms.uk          |  2 ++
 lib/ukallocpool/include/uk/allocpool.h | 30 ++++++++++++++++++++++++++
 lib/ukallocpool/pool.c                 | 29 +++++++++++++++++++++++++
 3 files changed, 61 insertions(+)

diff --git a/lib/ukallocpool/exportsyms.uk b/lib/ukallocpool/exportsyms.uk
index 68c16ebe..0f4c3de4 100644
--- a/lib/ukallocpool/exportsyms.uk
+++ b/lib/ukallocpool/exportsyms.uk
@@ -5,5 +5,7 @@ uk_allocpool_reqmem
 uk_allocpool_availcount
 uk_allocpool_objlen
 uk_allocpool_take
+uk_allocpool_take_batch
 uk_allocpool_return
+uk_allocpool_return_batch
 uk_allocpool2ukalloc
diff --git a/lib/ukallocpool/include/uk/allocpool.h 
b/lib/ukallocpool/include/uk/allocpool.h
index 1f6747f1..55bccb86 100644
--- a/lib/ukallocpool/include/uk/allocpool.h
+++ b/lib/ukallocpool/include/uk/allocpool.h
@@ -157,6 +157,22 @@ size_t uk_allocpool_objlen(struct uk_allocpool *p);
  */
 void *uk_allocpool_take(struct uk_allocpool *p);
 
+/**
+ * Get multiple objects from a pool.
+ *
+ * @param p
+ *  Pointer to memory pool.
+ * @param obj
+ *  Pointer to array that will be filled with pointers of
+ *  allocated objects from the pool.
+ * @param count
+ *  Maximum number of objects that should be taken from the pool.
+ * @return
+ *  Number of successfully allocated objects on the given array.
+ */
+unsigned int uk_allocpool_take_batch(struct uk_allocpool *p,
+                                    void *obj[], unsigned int count);
+
 /**
  * Return one object back to a pool.
  * HINT: It is recommended to use this call instead of uk_free() whenever
@@ -169,6 +185,20 @@ void *uk_allocpool_take(struct uk_allocpool *p);
  */
 void uk_allocpool_return(struct uk_allocpool *p, void *obj);
 
+/**
+ * Return multiple objects to a pool.
+ *
+ * @param p
+ *  Pointer to memory pool.
+ * @param obj
+ *  Pointer to array that with pointers of objects that
+ *  should be returned.
+ * @param count
+ *  Number of objects that are on the array.
+ */
+void uk_allocpool_return_batch(struct uk_allocpool *p,
+                              void *obj[], unsigned int count);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/ukallocpool/pool.c b/lib/ukallocpool/pool.c
index a7c3acf0..390f6b92 100644
--- a/lib/ukallocpool/pool.c
+++ b/lib/ukallocpool/pool.c
@@ -172,6 +172,23 @@ void *uk_allocpool_take(struct uk_allocpool *p)
        return _take_free_obj(p);
 }
 
+unsigned int uk_allocpool_take_batch(struct uk_allocpool *p,
+                                    void *obj[], unsigned int count)
+{
+       unsigned int i;
+
+       UK_ASSERT(p);
+       UK_ASSERT(obj);
+
+       for (i = 0; i < count; ++i) {
+               if (unlikely(uk_list_empty(&p->free_obj)))
+                       break;
+               obj[i] = _take_free_obj(p);
+       }
+
+       return i;
+}
+
 void uk_allocpool_return(struct uk_allocpool *p, void *obj)
 {
        UK_ASSERT(p);
@@ -179,6 +196,18 @@ void uk_allocpool_return(struct uk_allocpool *p, void *obj)
        _prepend_free_obj(p, obj);
 }
 
+void uk_allocpool_return_batch(struct uk_allocpool *p,
+                              void *obj[], unsigned int count)
+{
+       unsigned int i;
+
+       UK_ASSERT(p);
+       UK_ASSERT(obj);
+
+       for (i = 0; i < count; ++i)
+               _prepend_free_obj(p, obj[i]);
+}
+
 #if CONFIG_LIBUKALLOC_IFSTATS
 static ssize_t pool_availmem(struct uk_alloc *a)
 {
-- 
2.20.1