Make sparse's initalization be accessible at runtime. This
allows sparse mappings to be created after boot in a hotplug
situation.
This patch is separated from the previous one just to give an
indication how much of the sparse infrastructure is *just* for
hotplug memory.
Signed-off-by: Dave Hansen <[EMAIL PROTECTED]>
---
memhotplug-dave/include/linux/mmzone.h | 2
memhotplug-dave/mm/sparse.c | 72 ++++++++++++++++++++++++---------
2 files changed, 56 insertions(+), 18 deletions(-)
diff -puN mm/sparse.c~B-sparse-152-sparse-hotplug mm/sparse.c
--- memhotplug/mm/sparse.c~B-sparse-152-sparse-hotplug 2005-03-16
15:46:39.000000000 -0800
+++ memhotplug-dave/mm/sparse.c 2005-03-16 15:46:39.000000000 -0800
@@ -52,6 +52,40 @@ unsigned long __init node_memmap_size_by
return nr_pages * sizeof(struct page);
}
+static int sparse_init_one_section(struct mem_section *ms, int pnum, struct
page *mem_map)
+{
+ if (ms->section_mem_map &&
+ (ms->section_mem_map != SECTION_MARKED_PRESENT))
+ return -EEXIST;
+ /*
+ * Subtle, we encode the real pfn into the mem_map such that
+ * the identity pfn - section_mem_map will return the actual
+ * physical page frame number.
+ */
+ ms->section_mem_map = mem_map - (pnum << PFN_SECTION_SHIFT);
+
+ return 1;
+}
+
+static struct page *sparse_early_mem_map_alloc(int pnum)
+{
+ struct page *map;
+ int nid = early_pfn_to_nid(pnum << PFN_SECTION_SHIFT);
+
+ map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
+ if (map)
+ return map;
+
+ map = alloc_bootmem_node(NODE_DATA(nid),
+ sizeof(struct page) * PAGES_PER_SECTION);
+ if (map)
+ return map;
+
+ printk(KERN_WARNING "%s: allocation failed\n", __FUNCTION__);
+ mem_section[pnum].section_mem_map = 0;
+ return NULL;
+}
+
/*
* Allocate the accumulated non-linear sections, allocate a mem_map
* for each and record the physical to section mapping.
@@ -60,28 +94,30 @@ void sparse_init(void)
{
int pnum;
struct page *map;
- int nid;
for (pnum = 0; pnum < NR_MEM_SECTIONS; pnum++) {
if (!mem_section[pnum].section_mem_map)
continue;
- nid = early_pfn_to_nid(pnum << PFN_SECTION_SHIFT);
- map = alloc_remap(nid, sizeof(struct page) * PAGES_PER_SECTION);
- if (!map)
- map = alloc_bootmem_node(NODE_DATA(nid),
- sizeof(struct page) * PAGES_PER_SECTION);
- if (!map) {
- mem_section[pnum].section_mem_map = 0;
- continue;
- }
-
- /*
- * Subtle, we encode the real pfn into the mem_map such that
- * the identity pfn - section_mem_map will return the actual
- * physical page frame number.
- */
- mem_section[pnum].section_mem_map = map -
- (pnum << PFN_SECTION_SHIFT);
+ map = sparse_early_mem_map_alloc(pnum);
+ if (map)
+ sparse_init_one_section(&mem_section[pnum], pnum, map);
}
}
+
+/*
+ * returns the number of sections whose mem_maps were properly
+ * set. If this is <=0, then that means that the passed-in
+ * map was not consumed and must be freed.
+ */
+int sparse_add_one_section(int start_pfn, int nr_pages, struct page *map)
+{
+ struct mem_section *ms = __pfn_to_section(start_pfn);
+
+ if (ms->section_mem_map & SECTION_MARKED_PRESENT)
+ return -EEXIST;
+
+ ms->section_mem_map |= SECTION_MARKED_PRESENT;
+
+ return sparse_init_one_section(ms, start_pfn >> PFN_SECTION_SHIFT, map);
+}
diff -puN include/linux/mmzone.h~B-sparse-152-sparse-hotplug
include/linux/mmzone.h
--- memhotplug/include/linux/mmzone.h~B-sparse-152-sparse-hotplug
2005-03-16 15:46:39.000000000 -0800
+++ memhotplug-dave/include/linux/mmzone.h 2005-03-16 15:46:39.000000000
-0800
@@ -445,6 +445,8 @@ struct mem_section {
extern struct mem_section mem_section[NR_MEM_SECTIONS];
+#define SECTION_MARKED_PRESENT ((void *)-1)
+
/*
* Given a kernel address, find the home node of the underlying memory.
*/
_
