Commit c091dd96 authored by Baoquan He's avatar Baoquan He Committed by Andrew Morton
Browse files

mm/init: remove the unnecessary special treatment for memory-less node 

Because memory-less node's ->node_present_pages and its zone's
->present_pages are all 0, the judgement before calling node_set_state()
to set N_MEMORY, N_HIGH_MEMORY, N_NORMAL_MEMORY for node is enough to skip
memory-less node.  The 'continue;' statement inside for_each_node() loop
of free_area_init() is gilding the lily.

Here, remove the special handling to make memory-less node share the same
code flow as normal node.

And also rephrase the code comments above the 'continue' statement
and move them above above line 'if (pgdat->node_present_pages)'.

[bhe@redhat.com: redo code comments, per Mike]
  Link: https://lkml.kernel.org/r/ZhYJAVQRYJSTKZng@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20240326061134.1055295-3-bhe@redhat.com


Signed-off-by: default avatarBaoquan He <bhe@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 850ed205

mm/mm_init.c

+11 −16
Original line number Diff line number Diff line
@@ -1835,29 +1835,24 @@ void __init free_area_init(unsigned long *max_zone_pfn) 
				panic("Cannot allocate %zuB for node %d.\n",

				       sizeof(*pgdat), nid);

			arch_refresh_nodedata(nid, pgdat);

			free_area_init_node(nid);



			/*

			 * We do not want to confuse userspace by sysfs

			 * files/directories for node without any memory

			 * attached to it, so this node is not marked as

			 * N_MEMORY and not marked online so that no sysfs

			 * hierarchy will be created via register_one_node for

			 * it. The pgdat will get fully initialized by

			 * hotadd_init_pgdat() when memory is hotplugged into

			 * this node.

			 */

			continue;

		}



		pgdat = NODE_DATA(nid);

		free_area_init_node(nid);



		/* Any memory on that node */

		if (pgdat->node_present_pages)

		/*

		 * No sysfs hierarcy will be created via register_one_node()

		 *for memory-less node because here it's not marked as N_MEMORY

		 *and won't be set online later. The benefit is userspace

		 *program won't be confused by sysfs files/directories of

		 *memory-less node. The pgdat will get fully initialized by

		 *hotadd_init_pgdat() when memory is hotplugged into this node.

		 */

		if (pgdat->node_present_pages) {

			node_set_state(nid, N_MEMORY);

			check_for_memory(pgdat);

		}

	}



	calc_nr_kernel_pages();

	memmap_init();