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Re: [PATCH] i386: Increase MALLOC_ALIGNMENT to 16 [BZ #21120]
On Fri, Jun 30, 2017 at 7:31 AM, Joseph Myers <joseph@codesourcery.com> wrote:
> On Fri, 30 Jun 2017, Carlos O'Donell wrote:
>
>> (a) Should we add a new file malloc-alignment.h to specify a new parameter.
>> - Adds new file malloc-alignment.h.
>> - 2 new files.
>
> My preference is to add headers like this and so reduce the need for
> #ifndef (that is, have a generic malloc-alignment that includes the
> definition that's currently guarded with #ifndef).
>
I like this idea. Here is the patch. OK for master?
Thanks.
--
H.J.
From 1c13144a6252b1edc40c4900c6ea683aea6fc691 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.tools@gmail.com>
Date: Thu, 29 Jun 2017 10:26:04 -0700
Subject: [PATCH] i386: Increase MALLOC_ALIGNMENT to 16 [BZ #21120]
GCC 7 changed the definition of max_align_t on i386:
https://gcc.gnu.org/git/?p=gcc.git;a=commitdiff;h=9b5c49ef97e63cc63f1ffa13baf771368105ebe2
As a result, glibc malloc no longer returns memory blocks which are as
aligned as max_align_t requires.
This causes malloc/tst-malloc-thread-fail to fail with an error like this
one:
error: allocation function 0, size 144 not aligned to 16
This patch moves the MALLOC_ALIGNMENT definition to <malloc-alignment.h>
and increases the malloc alignment to 16 for i386.
[BZ #21120]
* malloc/malloc-internal.h (MALLOC_ALIGNMENT): Moved to ...
* sysdeps/generic/malloc-alignment.h: Here. New file.
* sysdeps/i386/malloc-alignment.h: Likewise.
* sysdeps/generic/malloc-machine.h: Include <malloc-alignment.h>.
---
malloc/malloc-internal.h | 10 ----------
sysdeps/generic/malloc-alignment.h | 31 +++++++++++++++++++++++++++++++
sysdeps/generic/malloc-machine.h | 1 +
sysdeps/i386/malloc-alignment.h | 24 ++++++++++++++++++++++++
4 files changed, 56 insertions(+), 10 deletions(-)
create mode 100644 sysdeps/generic/malloc-alignment.h
create mode 100644 sysdeps/i386/malloc-alignment.h
diff --git a/malloc/malloc-internal.h b/malloc/malloc-internal.h
index dbd801a..6a62717 100644
--- a/malloc/malloc-internal.h
+++ b/malloc/malloc-internal.h
@@ -58,16 +58,6 @@
/* The corresponding word size. */
#define SIZE_SZ (sizeof (INTERNAL_SIZE_T))
-/* MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks. It
- must be a power of two at least 2 * SIZE_SZ, even on machines for
- which smaller alignments would suffice. It may be defined as larger
- than this though. Note however that code and data structures are
- optimized for the case of 8-byte alignment. */
-#ifndef MALLOC_ALIGNMENT
-# define MALLOC_ALIGNMENT (2 * SIZE_SZ < __alignof__ (long double) \
- ? __alignof__ (long double) : 2 * SIZE_SZ)
-#endif
-
/* The corresponding bit mask value. */
#define MALLOC_ALIGN_MASK (MALLOC_ALIGNMENT - 1)
diff --git a/sysdeps/generic/malloc-alignment.h b/sysdeps/generic/malloc-alignment.h
new file mode 100644
index 0000000..efd03fa
--- /dev/null
+++ b/sysdeps/generic/malloc-alignment.h
@@ -0,0 +1,31 @@
+/* Define MALLOC_ALIGNMENT for malloc. Generic version.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _GENERIC_MALLOC_ALIGNMENT_H
+#define _GENERIC_MALLOC_ALIGNMENT_H
+
+/* MALLOC_ALIGNMENT is the minimum alignment for malloc'ed chunks. It
+ must be a power of two at least 2 * SIZE_SZ, even on machines for
+ which smaller alignments would suffice. It may be defined as larger
+ than this though. Note however that code and data structures are
+ optimized for the case of 8-byte alignment. */
+#define MALLOC_ALIGNMENT (2 * SIZE_SZ < __alignof__ (long double) \
+ ? __alignof__ (long double) : 2 * SIZE_SZ)
+
+
+#endif /* !defined(_GENERIC_MALLOC_ALIGNMENT_H) */
diff --git a/sysdeps/generic/malloc-machine.h b/sysdeps/generic/malloc-machine.h
index 21aa9fc..4491b90 100644
--- a/sysdeps/generic/malloc-machine.h
+++ b/sysdeps/generic/malloc-machine.h
@@ -21,6 +21,7 @@
#define _GENERIC_MALLOC_MACHINE_H
#include <atomic.h>
+#include <malloc-alignment.h>
#ifndef atomic_full_barrier
# define atomic_full_barrier() __asm ("" ::: "memory")
diff --git a/sysdeps/i386/malloc-alignment.h b/sysdeps/i386/malloc-alignment.h
new file mode 100644
index 0000000..f72f7a8
--- /dev/null
+++ b/sysdeps/i386/malloc-alignment.h
@@ -0,0 +1,24 @@
+/* Define MALLOC_ALIGNMENT for malloc. i386 version.
+ Copyright (C) 2017 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _I386_MALLOC_ALIGNMENT_H
+#define _I386_MALLOC_ALIGNMENT_H
+
+#define MALLOC_ALIGNMENT 16
+
+#endif /* !defined(_I386_MALLOC_ALIGNMENT_H) */
--
2.9.4