Re: [PATCH] Fix sparsemem on Cell

KAMEZAWA Hiroyuki
2006-12-16T08:03:53Z

On Fri, 15 Dec 2006 11:45:36 -0800
Andrew Morton <akpm@osdl.org> wrote:

> Perhaps if the function's role in the world was commented it would be clearer.
>

How about patch like this ? (this one is not tested.)
Already-exisiting-more-generic-flag is available ?

-Kame
==
include/linux/memory_hotplug.h | 8 ++++++++
mm/memory_hotplug.c | 14 ++++++++++++++
mm/page_alloc.c | 11 +++++++----
3 files changed, 29 insertions(+), 4 deletions(-)

Index: linux-2.6.20-rc1-mm1/include/linux/memory_hotplug.h
===================================================================
--- linux-2.6.20-rc1-mm1.orig/include/linux/memory_hotplug.h 2006-11-30 06:57:37.000000000 +0900
+++ linux-2.6.20-rc1-mm1/include/linux/memory_hotplug.h 2006-12-16 16:42:40.000000000 +0900
@@ -133,6 +133,10 @@
#endif /* CONFIG_NUMA */
#endif /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */

+extern int under_memory_hotadd(void);
+
+
+
#else /* ! CONFIG_MEMORY_HOTPLUG */
/*
* Stub functions for when hotplug is off
@@ -159,6 +163,10 @@
dump_stack();
return -ENOSYS;
}
+static inline int under_memory_hotadd()
+{
+ return 0;
+}

#endif /* ! CONFIG_MEMORY_HOTPLUG */
static inline int __remove_pages(struct zone *zone, unsigned long start_pfn,
Index: linux-2.6.20-rc1-mm1/mm/memory_hotplug.c
===================================================================
--- linux-2.6.20-rc1-mm1.orig/mm/memory_hotplug.c 2006-12-16 14:24:10.000000000 +0900
+++ linux-2.6.20-rc1-mm1/mm/memory_hotplug.c 2006-12-16 16:51:08.000000000 +0900
@@ -26,6 +26,17 @@

#include <asm/tlbflush.h>

+/*
+ * Because memory hotplug shares some codes for initilization with boot,
+ * we sometimes have to check what we are doing ?
+ */
+static atomic_t memory_hotadd_count;
+
+int under_memory_hotadd(void)
+{
+ return atomic_read(&memory_hotadd_count);
+}
+
/* add this memory to iomem resource */
static struct resource *register_memory_resource(u64 start, u64 size)
{
@@ -273,10 +284,13 @@
if (ret)
goto error;
}
+ atomic_inc(&memory_hotadd_count);

/* call arch's memory hotadd */
ret = arch_add_memory(nid, start, size);

+ atomic_dec(&memory_hotadd_count);
+
if (ret < 0)
goto error;

Index: linux-2.6.20-rc1-mm1/mm/page_alloc.c
===================================================================
--- linux-2.6.20-rc1-mm1.orig/mm/page_alloc.c 2006-12-16 14:24:38.000000000 +0900
+++ linux-2.6.20-rc1-mm1/mm/page_alloc.c 2006-12-16 16:53:02.000000000 +0900
@@ -2069,10 +2069,13 @@
unsigned long pfn;

for (pfn = start_pfn; pfn < end_pfn; pfn++) {
- if (!early_pfn_valid(pfn))
- continue;
- if (!early_pfn_in_nid(pfn, nid))
- continue;
+ if (!under_memory_hotadd()) {
+ /* we are in boot */
+ if (!early_pfn_valid(pfn))
+ continue;
+ if (!early_pfn_in_nid(pfn, nid))
+ continue;
+ }
page = pfn_to_page(pfn);
set_page_links(page, zone, nid, pfn);
init_page_count(page);