On Mon, Aug 05, 2024 at 01:03:56PM -0700, Dan Williams wrote:

Mike Rapoport wrote:

quoted

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

Instead of looping over numa_meminfo array to detect node's start and
end addresses use get_pfn_range_for_init().

This is shorter and make it easier to lift numa_memblks to generic code.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Tested-by: Zi Yan <ziy@nvidia.com> # for x86_64 and arm64
---
 arch/x86/mm/numa.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index edfc38803779..cfe7e5477cf8 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c

@@ -521,17 +521,10 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)
 
 	/* Finally register nodes. */
 	for_each_node_mask(nid, node_possible_map) {
-		u64 start = PFN_PHYS(max_pfn);
-		u64 end = 0;
+		unsigned long start_pfn, end_pfn;
 
-		for (i = 0; i < mi->nr_blks; i++) {
-			if (nid != mi->blk[i].nid)
-				continue;
-			start = min(mi->blk[i].start, start);
-			end = max(mi->blk[i].end, end);
-		}
-
-		if (start >= end)
+		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
+		if (start_pfn >= end_pfn)

Assuming I understand why this works, would it be worth a comment like:

"Note, get_pfn_range_for_nid() depends on memblock_set_node() having
 already happened"

Will add a comment, sure.
 

...at least that context was not part of the diff so took me second to
figure out how this works.

-- 
Sincerely yours,
Mike.