driver core: Convert link_mem_sections to use find_memory_block_hinted.

Modify link_mem_sections() to pass in the previous mem_block as a hint to
locating the next mem_block.  Since they are typically added in order this
results in a massive saving in time during boot of a very large system.
For example, on a 16TB x86_64 machine, it reduced the total time spent
linking all node's memory sections from 1 hour, 27 minutes to 46 seconds.

Signed-off-by: Robin Holt <holt@sgi.com>
To: Gary Hade <garyhade@us.ibm.com>
To: Badari Pulavarty <pbadari@us.ibm.com>
To: Ingo Molnar <mingo@elte.hu>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 2872e86837b2..ee53558b452f 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -409,25 +409,27 @@ static int link_mem_sections(int nid)
         unsigned long start_pfn = NODE_DATA(nid)->node_start_pfn;
         unsigned long end_pfn = start_pfn + NODE_DATA(nid)->node_spanned_pages;
         unsigned long pfn;
+        struct memory_block *mem_blk = NULL;
         int err = 0;
 
         for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
                 unsigned long section_nr = pfn_to_section_nr(pfn);
                 struct mem_section *mem_sect;
-                struct memory_block *mem_blk;
                 int ret;
 
                 if (!present_section_nr(section_nr))
                         continue;
                 mem_sect = __nr_to_section(section_nr);
-                mem_blk = find_memory_block(mem_sect);
+                mem_blk = find_memory_block_hinted(mem_sect, mem_blk);
                 ret = register_mem_sect_under_node(mem_blk, nid);
                 if (!err)
                         err = ret;
 
                 /* discard ref obtained in find_memory_block() */
-                kobject_put(&mem_blk->sysdev.kobj);
         }
+
+        if (mem_blk)
+                kobject_put(&mem_blk->sysdev.kobj);
         return err;
 }