[PATCH 14/15] x86/numa: remove redundant iteration over memblock.reserved

Mike Rapoport
2020-07-28T05:14:36Z

From: Mike Rapoport <rppt@linux.ibm.com>

numa_clear_kernel_node_hotplug() function first traverses numa_meminfo
regions to set node ID in memblock.reserved and than traverses
memblock.reserved to update reserved_nodemask to include node IDs that were
set in the first loop.

Remove redundant traversal over memblock.reserved and update
reserved_nodemask while iterating over numa_meminfo.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
---
arch/x86/mm/numa.c | 26 ++++++++++----------------
1 file changed, 10 insertions(+), 16 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 8ee952038c80..4078abd33938 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -498,31 +498,25 @@ static void __init numa_clear_kernel_node_hotplug(void)
* and use those ranges to set the nid in memblock.reserved.
* This will split up the memblock regions along node
* boundaries and will set the node IDs as well.
+ *
+ * The nid will also be set in reserved_nodemask which is later
+ * used to clear MEMBLOCK_HOTPLUG flag.
+ *
+ * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
+ * numa_meminfo might not include all memblock.reserved
+ * memory ranges, because quirks such as trim_snb_memory()
+ * reserve specific pages for Sandy Bridge graphics.
+ * These ranges will remain with nid == MAX_NUMNODES. ]
*/
for (i = 0; i < numa_meminfo.nr_blks; i++) {
struct numa_memblk *mb = numa_meminfo.blk + i;
int ret;

ret = memblock_set_node(mb->start, mb->end - mb->start, &memblock.reserved, mb->nid);
+ node_set(mb->nid, reserved_nodemask);
WARN_ON_ONCE(ret);
}

- /*
- * Now go over all reserved memblock regions, to construct a
- * node mask of all kernel reserved memory areas.
- *
- * [ Note, when booting with mem=nn[kMG] or in a kdump kernel,
- * numa_meminfo might not include all memblock.reserved
- * memory ranges, because quirks such as trim_snb_memory()
- * reserve specific pages for Sandy Bridge graphics. ]
- */
- for_each_memblock(reserved, mb_region) {
- int nid = memblock_get_region_node(mb_region);
-
- if (nid != MAX_NUMNODES)
- node_set(nid, reserved_nodemask);
- }
-
/*
* Finally, clear the MEMBLOCK_HOTPLUG flag for all memory
* belonging to the reserved node mask.
--
2.26.2