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

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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: Baoquan He <bhe@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "Mike Rapoport (IBM)" <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Baoquan He 2024-03-26 14:11:28 +08:00 committed by Andrew Morton
parent 850ed20539
commit c091dd963f
1 changed files with 11 additions and 16 deletions
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27
mm/mm_init.c
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@ -1835,28 +1835,23 @@ 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);
check_for_memory(pgdat);
}
}
calc_nr_kernel_pages();