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Don't always zero memory in malloc(). This saves around 2us on a

full-length PKB allocation.
tags/v0.9.3
Michael Brown il y a 18 ans
Parent
révision
35776f481c
2 fichiers modifiés avec 23 ajouts et 6 suppressions
  1. 17
    2
      src/core/malloc.c
  2. 6
    4
      src/include/stdlib.h

+ 17
- 2
src/core/malloc.c Voir le fichier

@@ -134,8 +134,6 @@ void * alloc_memblock ( size_t size, size_t align ) {
134 134
 			 */
135 135
 			if ( pre_size < MIN_MEMBLOCK_SIZE )
136 136
 				list_del ( &pre->list );
137
-			/* Zero allocated memory, for calloc() */
138
-			memset ( block, 0, size );
139 137
 			DBG ( "Allocated [%p,%p)\n", block,
140 138
 			      ( ( ( void * ) block ) + size ) );
141 139
 			return block;
@@ -297,6 +295,23 @@ void free ( void *ptr ) {
297 295
 	realloc ( ptr, 0 );
298 296
 }
299 297
 
298
+/**
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+ * Allocate cleared memory
300
+ *
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+ * @v size		Requested size
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+ * @ret ptr		Allocated memory
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+ *
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+ * Allocate memory as per malloc(), and zero it.
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+ */
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+void * _calloc ( size_t size ) {
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+	void *data;
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+
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+	data = malloc ( size );
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+	if ( data )
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+		memset ( data, 0, size );
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+	return data;
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+}
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+
300 315
 /**
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  * Add memory to allocation pool
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  *

+ 6
- 4
src/include/stdlib.h Voir le fichier

@@ -8,6 +8,8 @@ extern void free ( void *ptr );
8 8
 extern int system ( const char *command );
9 9
 extern long int random ( void );
10 10
 
11
+extern void * _calloc ( size_t len );
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+
11 13
 /**
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  * Allocate cleared memory
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  *
@@ -17,12 +19,12 @@ extern long int random ( void );
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  *
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  * Allocate memory as per malloc(), and zero it.
19 21
  *
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- * Note that malloc() and calloc() are identical, in the interests of
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- * reducing code size.  Callers should not, however, rely on malloc()
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- * clearing memory, since this behaviour may change in future.
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+ * This is implemented as a static inline, with the body of the
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+ * function in _calloc(), since in most cases @c nmemb will be 1 and
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+ * doing the multiply is just wasteful.
23 25
  */
24 26
 static inline void * calloc ( size_t nmemb, size_t size ) {
25
-	return malloc ( nmemb * size );
27
+	return _calloc ( nmemb * size );
26 28
 }
27 29
 
28 30
 #endif /* STDLIB_H */

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