svn commit: r334545 - in head/sys: contrib/zstd/lib/freebsd kern netinet/libalias sys

[Mateusz Guzik]

Author: mjg
Date: Sat Jun  2 22:20:09 2018
New Revision: 334545
URL: https://svnweb.freebsd.org/changeset/base/334545

Log:
  malloc: try to use builtins for zeroing at the callsite
  
  Plenty of allocation sites pass M_ZERO and sizes which are small and known
  at compilation time. Handling them internally in malloc loses this information
  and results in avoidable calls to memset.
  
  Instead, let the compiler take the advantage of it whenever possible.
  
  Discussed with:	jeff

Modified:
  head/sys/contrib/zstd/lib/freebsd/stdlib.h
  head/sys/kern/kern_malloc.c
  head/sys/netinet/libalias/alias_mod.h
  head/sys/sys/malloc.h

Modified: head/sys/contrib/zstd/lib/freebsd/stdlib.h
==============================================================================
--- head/sys/contrib/zstd/lib/freebsd/stdlib.h	Sat Jun  2 22:12:57 2018	(r334544)
+++ head/sys/contrib/zstd/lib/freebsd/stdlib.h	Sat Jun  2 22:20:09 2018	(r334545)
@@ -35,6 +35,7 @@
 
 MALLOC_DECLARE(M_ZSTD);
 
+#undef malloc
 #define	malloc(x)	(malloc)((x), M_ZSTD, M_WAITOK)
 #define	free(x)		(free)((x), M_ZSTD)
 #define	calloc(a, b)	(mallocarray)((a), (b), M_ZSTD, M_WAITOK | M_ZERO)

Modified: head/sys/kern/kern_malloc.c
==============================================================================
--- head/sys/kern/kern_malloc.c	Sat Jun  2 22:12:57 2018	(r334544)
+++ head/sys/kern/kern_malloc.c	Sat Jun  2 22:20:09 2018	(r334545)
@@ -549,7 +549,7 @@ malloc_dbg(caddr_t *vap, size_t *sizep, struct malloc_
  *	the allocation fails.
  */
 void *
-malloc(size_t size, struct malloc_type *mtp, int flags)
+(malloc)(size_t size, struct malloc_type *mtp, int flags)
 {
 	int indx;
 	caddr_t va;

Modified: head/sys/netinet/libalias/alias_mod.h
==============================================================================
--- head/sys/netinet/libalias/alias_mod.h	Sat Jun  2 22:12:57 2018	(r334544)
+++ head/sys/netinet/libalias/alias_mod.h	Sat Jun  2 22:20:09 2018	(r334545)
@@ -41,6 +41,7 @@ MALLOC_DECLARE(M_ALIAS);
 
 /* Use kernel allocator. */
 #if defined(_SYS_MALLOC_H_)
+#undef malloc
 #define	malloc(x)	malloc(x, M_ALIAS, M_NOWAIT|M_ZERO)
 #define	calloc(n, x)	mallocarray((n), (x), M_ALIAS, M_NOWAIT|M_ZERO)
 #define	free(x)		free(x, M_ALIAS)

Modified: head/sys/sys/malloc.h
==============================================================================
--- head/sys/sys/malloc.h	Sat Jun  2 22:12:57 2018	(r334544)
+++ head/sys/sys/malloc.h	Sat Jun  2 22:20:09 2018	(r334545)
@@ -38,6 +38,9 @@
 #define	_SYS_MALLOC_H_
 
 #include <sys/param.h>
+#ifdef _KERNEL
+#include <sys/systm.h>
+#endif
 #include <sys/queue.h>
 #include <sys/_lock.h>
 #include <sys/_mutex.h>
@@ -183,6 +186,22 @@ void	free(void *addr, struct malloc_type *type);
 void	free_domain(void *addr, struct malloc_type *type);
 void	*malloc(size_t size, struct malloc_type *type, int flags) __malloc_like
 	    __result_use_check __alloc_size(1);
+#ifdef _KERNEL
+#define	malloc(size, type, flags) ({					\
+	void *_malloc_item;						\
+	size_t _size = (size);						\
+	if (__builtin_constant_p(size) && __builtin_constant_p(flags) &&\
+	    ((flags) & M_ZERO)) {					\
+		_malloc_item = malloc(_size, type, (flags) &~ M_ZERO);	\
+		if (((flags) & M_WAITOK) || _malloc_item != NULL)	\
+			bzero(_malloc_item, _size);			\
+	} else {							\
+		_malloc_item = malloc(_size, type, flags);		\
+	}								\
+	_malloc_item;							\
+})
+#endif
+
 void	*malloc_domain(size_t size, struct malloc_type *type, int domain,
 	    int flags) __malloc_like __result_use_check __alloc_size(1);
 void	*mallocarray(size_t nmemb, size_t size, struct malloc_type *type,