hotplug memory remove: generic __remove_pages() support
Generic helper function to remove section mappings and sysfs entries for the
section of the memory we are removing. offline_pages() correctly adjusted
zone and marked the pages reserved.
TODO: Yasunori Goto is working on patches to free up allocations from bootmem.
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/sparse.c b/mm/sparse.c
index 7e919138..186a85b 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -208,12 +208,13 @@
}
/*
- * We need this if we ever free the mem_maps. While not implemented yet,
- * this function is included for parity with its sibling.
+ * Decode mem_map from the coded memmap
*/
-static __attribute((unused))
+static
struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pnum)
{
+ /* mask off the extra low bits of information */
+ coded_mem_map &= SECTION_MAP_MASK;
return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);
}
@@ -404,6 +405,28 @@
}
#endif /* CONFIG_SPARSEMEM_VMEMMAP */
+static void free_section_usemap(struct page *memmap, unsigned long *usemap)
+{
+ if (!usemap)
+ return;
+
+ /*
+ * Check to see if allocation came from hot-plug-add
+ */
+ if (PageSlab(virt_to_page(usemap))) {
+ kfree(usemap);
+ if (memmap)
+ __kfree_section_memmap(memmap, PAGES_PER_SECTION);
+ return;
+ }
+
+ /*
+ * TODO: Allocations came from bootmem - how do I free up ?
+ */
+ printk(KERN_WARNING "Not freeing up allocations from bootmem "
+ "- leaking memory\n");
+}
+
/*
* returns the number of sections whose mem_maps were properly
* set. If this is <=0, then that means that the passed-in
@@ -456,4 +479,20 @@
}
return ret;
}
+
+void sparse_remove_one_section(struct zone *zone, struct mem_section *ms)
+{
+ struct page *memmap = NULL;
+ unsigned long *usemap = NULL;
+
+ if (ms->section_mem_map) {
+ usemap = ms->pageblock_flags;
+ memmap = sparse_decode_mem_map(ms->section_mem_map,
+ __section_nr(ms));
+ ms->section_mem_map = 0;
+ ms->pageblock_flags = NULL;
+ }
+
+ free_section_usemap(memmap, usemap);
+}
#endif