Module: xenomai-3
Branch: wip/dovetail
Commit: 00ecc7cb46166bf983209b6e9a5090b05dc6472c
URL:
http://git.xenomai.org/?p=xenomai-3.git;a=commit;h=00ecc7cb46166bf983209b6e9a5090b05dc6472c
Author: Philippe Gerum <r...@xenomai.org>
Date: Sun Feb 28 08:23:32 2016 +0100
cobalt/init: get main heap memory from vmalloc()
There is no reason to ask for physically contiguous memory from
alloc_pages[_exact]() for the main heap: real-time heaps are certainly
no place for getting DMA-suitable buffers from.
Using alloc_pages*() for common Cobalt heaps is a problem:
- this raises the probability of getting allocation failures in case
of memory fragmentation (although seldom at boot time, some
Cobalt-based modules also using such services could fail allocating
their heap later on).
- this restricts the maximum heap size to MAX_ORDER (currently 4Mb),
which may be too small in some configurations.
Therefore, switch from alloc_pages_exact() to vmalloc().
---
include/cobalt/kernel/heap.h | 4 ++++
kernel/cobalt/heap.c | 28 ++++++++++++++++++++++++++++
kernel/cobalt/init.c | 7 +++----
3 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/include/cobalt/kernel/heap.h b/include/cobalt/kernel/heap.h
index 988004f..a1cea69 100644
--- a/include/cobalt/kernel/heap.h
+++ b/include/cobalt/kernel/heap.h
@@ -130,6 +130,10 @@ static inline void xnheap_cleanup_proc(void) { }
/* Public interface. */
+void *xnheap_vmalloc(size_t size);
+
+void xnheap_vfree(void *p);
+
int xnheap_init(struct xnheap *heap, void *membase, u32 size);
void xnheap_set_name(struct xnheap *heap,
diff --git a/kernel/cobalt/heap.c b/kernel/cobalt/heap.c
index 70f1c8f..2fcb6ba 100644
--- a/kernel/cobalt/heap.c
+++ b/kernel/cobalt/heap.c
@@ -21,6 +21,8 @@
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/log2.h>
+#include <linux/kconfig.h>
+#include <asm/pgtable.h>
#include <cobalt/kernel/assert.h>
#include <cobalt/kernel/heap.h>
#include <cobalt/kernel/vfile.h>
@@ -655,4 +657,30 @@ out:
}
EXPORT_SYMBOL_GPL(xnheap_check_block);
+void *xnheap_vmalloc(size_t size)
+{
+ /*
+ * We want memory used in real-time context to be pulled from
+ * ZONE_NORMAL, however we don't need it to be physically
+ * contiguous.
+ *
+ * 32bit systems which would need HIGHMEM for running a Cobalt
+ * configuration would also be required to support PTE
+ * pinning, which not all architectures provide. Moreover,
+ * pinning PTEs eagerly for a potentially (very) large amount
+ * of memory may quickly degrade performance.
+ *
+ * If using a different kernel/user memory split cannot be the
+ * answer for those configs, it's likely that basing such
+ * software on a 32bit system had to be wrong in the first
+ * place anyway.
+ */
+ return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
+}
+
+void xnheap_vfree(void *p)
+{
+ vfree(p);
+}
+
/** @} */
diff --git a/kernel/cobalt/init.c b/kernel/cobalt/init.c
index 0eab3be..6cbb67b 100644
--- a/kernel/cobalt/init.c
+++ b/kernel/cobalt/init.c
@@ -18,6 +18,7 @@
*/
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/vmalloc.h>
#include <linux/ipipe_tickdev.h>
#include <xenomai/version.h>
#include <cobalt/kernel/sched.h>
@@ -127,7 +128,6 @@ static void sys_shutdown(void)
struct xnthread *thread, *tmp;
struct xnsched *sched;
void *membase;
- u32 memsize;
int cpu;
spl_t s;
@@ -155,9 +155,8 @@ static void sys_shutdown(void)
xnregistry_cleanup();
membase = xnheap_get_membase(&cobalt_heap);
- memsize = xnheap_get_size(&cobalt_heap);
xnheap_destroy(&cobalt_heap);
- free_pages_exact(membase, memsize);
+ vfree(membase);
}
static int __init mach_setup(void)
@@ -290,7 +289,7 @@ static __init int sys_init(void)
if (sysheap_size_arg == 0)
sysheap_size_arg = CONFIG_XENO_OPT_SYS_HEAPSZ;
- heapaddr = alloc_pages_exact(sysheap_size_arg * 1024, GFP_KERNEL);
+ heapaddr = vmalloc(sysheap_size_arg * 1024);
if (heapaddr == NULL ||
xnheap_init(&cobalt_heap, heapaddr, sysheap_size_arg * 1024)) {
return -ENOMEM;
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