[PATCH v2 0/9] treewide, numa_memblks: remove redundant work during NUMA init

[PATCH v2 0/9] treewide, numa_memblks: remove redundant work during NUMA init

[Sang-Heon Jeon]

Every existing numa_add_memblk() caller passes a valid node id and
separately marks that node in numa_nodes_parsed with node_set(). In
addition, numa_nodemask_from_meminfo() recomputes the same "nodes that own
memory" set from numa_meminfo, which numa_nodes_parsed already contains.

This redundancy implicitly depends on the callers' node_set(). So, before
removing the redundancy, make numa_add_memblk() set the node in
numa_nodes_parsed explicitly. Then remove the per-caller node_set() and
numa_nodemask_from_meminfo().

Also, since the generic numa_register_meminfo() already sets
node_possible_map to numa_nodes_parsed, remove the duplicate assignment in
arch_numa's numa_register_nodes().

Patch 1 adds the node_set() to numa_add_memblk() itself, so every memblk's
node is set in numa_nodes_parsed on add.

Patches 2-6 depend on patch 1 and remove the redundant per-caller node_set()
from all callers.

Patch 7 removes both numa_nodemask_from_meminfo() call sites and the unused
function itself.

Patch 8 removes the duplicate node_possible_map assignment in arch_numa.

Patch 9 is a minor cleanup, using the existing numa_add_reserved_memblk()
wrapper in numa_cleanup_meminfo().

No functional change.

---
Changes from v1 [1]
- remove warning in numa_add_memblk_to() when start == end
- add Acked-by tag
- rebased onto latest mm-new

[1] https://lore.kernel.org/all/20260628135828.1393120-1-ekffu200098@gmail.com/
--- 

Sang-Heon Jeon (9):
  mm: numa_memblks: set numa_nodes_parsed in numa_add_memblk()
  ACPI: NUMA: remove redundant numa_nodes_parsed node_set()
  of/numa: remove redundant numa_nodes_parsed node_set()
  x86/numa: remove redundant numa_nodes_parsed node_set()
  arch_numa: remove redundant numa_nodes_parsed node_set()
  LoongArch: remove redundant numa_nodes_parsed node_set()
  mm: numa_memblks: remove redundant numa_nodemask_from_meminfo()
  arch_numa: remove redundant node_possible_map assignment
  mm: numa_memblks: use numa_add_reserved_memblk() in
    numa_cleanup_meminfo()

 arch/loongarch/kernel/numa.c |  1 -
 arch/x86/mm/amdtopology.c    |  1 -
 arch/x86/mm/numa.c           |  1 -
 drivers/acpi/numa/srat.c     |  2 --
 drivers/base/arch_numa.c     |  4 ----
 drivers/of/of_numa.c         |  5 +----
 mm/numa_memblks.c            | 39 +++++++++++++++++-------------------
 7 files changed, 19 insertions(+), 34 deletions(-)

-- 
2.43.0

[PATCH v2 1/9] mm: numa_memblks: set numa_nodes_parsed in numa_add_memblk()

[Sang-Heon Jeon]

Every existing numa_add_memblk() caller separately marks the new node in
numa_nodes_parsed with node_set().  Set the node in numa_add_memblk() itself
on a successful add, so this no longer depends on each caller.

numa_add_memblk_to() now returns -EINVAL for an out-of-range node id, so a
zero return implies @nid was valid.  No caller passes an invalid one, so
existing callers are unaffected.

The per-caller node_set() calls are removed in later patches.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 mm/numa_memblks.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
index 3c3c4eac3514..9815192549c3 100644
--- a/mm/numa_memblks.c
+++ b/mm/numa_memblks.c
@@ -135,13 +135,20 @@ EXPORT_SYMBOL(__node_distance);
 static int __init numa_add_memblk_to(int nid, u64 start, u64 end,
 				     struct numa_meminfo *mi)
 {
+	/* whine about and ignore invalid nid */
+	if (nid < 0 || nid >= MAX_NUMNODES) {
+		pr_warn("Warning: invalid memblk node id %d [mem %#010Lx-%#010Lx]\n",
+			nid, start, end - 1);
+		return -EINVAL;
+	}
+
 	/* ignore zero length blks */
 	if (start == end)
 		return 0;
 
 	/* whine about and ignore invalid blks */
-	if (start > end || nid < 0 || nid >= MAX_NUMNODES) {
-		pr_warn("Warning: invalid memblk node %d [mem %#010Lx-%#010Lx]\n",
+	if (start > end) {
+		pr_warn("Warning: invalid memblk node size %d [mem %#010Lx-%#010Lx]\n",
 			nid, start, end - 1);
 		return 0;
 	}
@@ -193,13 +200,20 @@ static void __init numa_move_tail_memblk(struct numa_meminfo *dst, int idx,
  * @end: End address of the new memblk
  *
  * Add a new memblk to the default numa_meminfo.
+ * On success @nid is also set in numa_nodes_parsed.
  *
  * RETURNS:
  * 0 on success, -errno on failure.
  */
 int __init numa_add_memblk(int nid, u64 start, u64 end)
 {
-	return numa_add_memblk_to(nid, start, end, &numa_meminfo);
+	int ret;
+
+	ret = numa_add_memblk_to(nid, start, end, &numa_meminfo);
+	if (!ret)
+		node_set(nid, numa_nodes_parsed);
+
+	return ret;
 }
 
 /**
-- 
2.43.0

[PATCH v2 2/9] ACPI: NUMA: remove redundant numa_nodes_parsed node_set()

[Sang-Heon Jeon]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 drivers/acpi/numa/srat.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index 62d4a8df0b8c..5c407dc6401e 100644
--- a/drivers/acpi/numa/srat.c
+++ b/drivers/acpi/numa/srat.c
@@ -399,8 +399,6 @@ acpi_parse_memory_affinity(union acpi_subtable_headers *header,
 		goto out_err_bad_srat;
 	}
 
-	node_set(node, numa_nodes_parsed);
-
 	pr_info("SRAT: Node %u PXM %u [mem %#010Lx-%#010Lx]%s%s\n",
 		node, pxm,
 		(unsigned long long) start, (unsigned long long) end - 1,
-- 
2.43.0

[PATCH v2 3/9] of/numa: remove redundant numa_nodes_parsed node_set()

[Sang-Heon Jeon]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
---
 drivers/of/of_numa.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/of/of_numa.c b/drivers/of/of_numa.c
index cd2dc8e825c9..230d5f628c1b 100644
--- a/drivers/of/of_numa.c
+++ b/drivers/of/of_numa.c
@@ -59,11 +59,8 @@ static int __init of_numa_parse_memory_nodes(void)
 			r = -EINVAL;
 		}
 
-		for (i = 0; !r && !of_address_to_resource(np, i, &rsrc); i++) {
+		for (i = 0; !r && !of_address_to_resource(np, i, &rsrc); i++)
 			r = numa_add_memblk(nid, rsrc.start, rsrc.end + 1);
-			if (!r)
-				node_set(nid, numa_nodes_parsed);
-		}
 
 		if (!i || r) {
 			of_node_put(np);
-- 
2.43.0

[PATCH v2 4/9] x86/numa: remove redundant numa_nodes_parsed node_set()

[Sang-Heon Jeon]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 arch/x86/mm/amdtopology.c | 1 -
 arch/x86/mm/numa.c        | 1 -
 2 files changed, 2 deletions(-)

diff --git a/arch/x86/mm/amdtopology.c b/arch/x86/mm/amdtopology.c
index f980b0eb0105..1cb581bbf2b6 100644
--- a/arch/x86/mm/amdtopology.c
+++ b/arch/x86/mm/amdtopology.c
@@ -150,7 +150,6 @@ int __init amd_numa_init(void)
 
 		prevbase = base;
 		numa_add_memblk(nodeid, base, limit);
-		node_set(nodeid, numa_nodes_parsed);
 	}
 
 	if (nodes_empty(numa_nodes_parsed))
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 99d0a9332c14..ced66e68a68e 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -216,7 +216,6 @@ static int __init dummy_numa_init(void)
 	printk(KERN_INFO "Faking a node at [mem %#018Lx-%#018Lx]\n",
 	       0LLU, PFN_PHYS(max_pfn) - 1);
 
-	node_set(0, numa_nodes_parsed);
 	node_set(0, numa_phys_nodes_parsed);
 	numa_add_memblk(0, 0, PFN_PHYS(max_pfn));
 
-- 
2.43.0

[PATCH v2 5/9] arch_numa: remove redundant numa_nodes_parsed node_set()

[Sang-Heon Jeon]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 drivers/base/arch_numa.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index 442ea239bba7..c7f63c4cf367 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c
@@ -279,7 +279,6 @@ static int __init dummy_numa_init(void)
 		pr_err("NUMA init failed\n");
 		return ret;
 	}
-	node_set(0, numa_nodes_parsed);
 
 	numa_off = true;
 	return 0;
-- 
2.43.0

[PATCH v2 6/9] LoongArch: remove redundant numa_nodes_parsed node_set()

[Sang-Heon Jeon]

numa_add_memblk() now sets the node in numa_nodes_parsed itself, so the
caller's own node_set() is redundant.  Remove it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 arch/loongarch/kernel/numa.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/loongarch/kernel/numa.c b/arch/loongarch/kernel/numa.c
index 8b89898e20df..c96c53623715 100644
--- a/arch/loongarch/kernel/numa.c
+++ b/arch/loongarch/kernel/numa.c
@@ -216,7 +216,6 @@ static int __init fake_numa_init(void)
 	phys_addr_t start = memblock_start_of_DRAM();
 	phys_addr_t end = memblock_end_of_DRAM() - 1;
 
-	node_set(0, numa_nodes_parsed);
 	pr_info("Faking a node at [mem %pap-%pap]\n", &start, &end);
 
 	return numa_add_memblk(0, start, end + 1);
-- 
2.43.0

[PATCH v2 7/9] mm: numa_memblks: remove redundant numa_nodemask_from_meminfo()

[Sang-Heon Jeon]

numa_add_memblk() now sets each added node in numa_nodes_parsed, so
numa_nodes_parsed already contains every node that owns memory.  The nodes
numa_nodemask_from_meminfo() adds from numa_meminfo are already set, so the
calls in numa_alloc_distance() and numa_register_meminfo() are redundant.

So remove both call sites and the unused function itself.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 mm/numa_memblks.c | 16 ----------------
 1 file changed, 16 deletions(-)

diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
index 9815192549c3..48428060e93f 100644
--- a/mm/numa_memblks.c
+++ b/mm/numa_memblks.c
@@ -17,20 +17,6 @@ nodemask_t numa_nodes_parsed __initdata;
 static struct numa_meminfo numa_meminfo __initdata_or_meminfo;
 static struct numa_meminfo numa_reserved_meminfo __initdata_or_meminfo;
 
-/*
- * Set nodes, which have memory in @mi, in *@nodemask.
- */
-static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
-					      const struct numa_meminfo *mi)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(mi->blk); i++)
-		if (mi->blk[i].start != mi->blk[i].end &&
-		    mi->blk[i].nid != NUMA_NO_NODE)
-			node_set(mi->blk[i].nid, *nodemask);
-}
-
 /**
  * numa_reset_distance - Reset NUMA distance table
  *
@@ -56,7 +42,6 @@ static int __init numa_alloc_distance(void)
 
 	/* size the new table and allocate it */
 	nodes_parsed = numa_nodes_parsed;
-	numa_nodemask_from_meminfo(&nodes_parsed, &numa_meminfo);
 
 	for_each_node_mask(i, nodes_parsed)
 		cnt = i;
@@ -415,7 +400,6 @@ static int __init numa_register_meminfo(struct numa_meminfo *mi)
 
 	/* Account for nodes with cpus and no memory */
 	node_possible_map = numa_nodes_parsed;
-	numa_nodemask_from_meminfo(&node_possible_map, mi);
 	if (WARN_ON(nodes_empty(node_possible_map)))
 		return -EINVAL;
 
-- 
2.43.0

[PATCH v2 8/9] arch_numa: remove redundant node_possible_map assignment

[Sang-Heon Jeon]

numa_register_meminfo() sets node_possible_map to numa_nodes_parsed.  The
later assignment in numa_register_nodes() is therefore redundant, so remove
it.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 drivers/base/arch_numa.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/base/arch_numa.c b/drivers/base/arch_numa.c
index c7f63c4cf367..6476227b772c 100644
--- a/drivers/base/arch_numa.c
+++ b/drivers/base/arch_numa.c
@@ -221,9 +221,6 @@ static int __init numa_register_nodes(void)
 		node_set_online(nid);
 	}
 
-	/* Setup online nodes to actual nodes*/
-	node_possible_map = numa_nodes_parsed;
-
 	return 0;
 }
 
-- 
2.43.0

[PATCH v2 9/9] mm: numa_memblks: use numa_add_reserved_memblk() in numa_cleanup_meminfo()

[Sang-Heon Jeon]

numa_cleanup_meminfo() calls the internal numa_add_memblk_to() to add a
block to numa_reserved_meminfo, even though numa_add_reserved_memblk() wraps
exactly that.

Use the wrapper instead, so numa_add_memblk_to() is reached only through its
two wrappers.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 mm/numa_memblks.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/numa_memblks.c b/mm/numa_memblks.c
index 48428060e93f..426d17ff6859 100644
--- a/mm/numa_memblks.c
+++ b/mm/numa_memblks.c
@@ -255,8 +255,7 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
 
 		/* preserve info for non-RAM areas above 'max_pfn': */
 		if (bi->end > high) {
-			numa_add_memblk_to(bi->nid, high, bi->end,
-					   &numa_reserved_meminfo);
+			numa_add_reserved_memblk(bi->nid, high, bi->end);
 			bi->end = high;
 		}
 
-- 
2.43.0

Re: [PATCH v2 0/9] treewide, numa_memblks: remove redundant work during NUMA init

[Mike Rapoport]

On Fri,  3 Jul 2026 13:13:20 +0900, Sang-Heon Jeon wrote:
> Every existing numa_add_memblk() caller passes a valid node id and
> separately marks that node in numa_nodes_parsed with node_set(). In
> addition, numa_nodemask_from_meminfo() recomputes the same "nodes that own
> memory" set from numa_meminfo, which numa_nodes_parsed already contains.
> 
> This redundancy implicitly depends on the callers' node_set(). So, before
> removing the redundancy, make numa_add_memblk() set the node in
> numa_nodes_parsed explicitly. Then remove the per-caller node_set() and
> numa_nodemask_from_meminfo().
> 
> [...]

Applied to numa_memblks-redundant-work branch of memblock.git tree, thanks!

[1/9] mm: numa_memblks: set numa_nodes_parsed in numa_add_memblk()
      commit: abdbd8329281f40afd381346410d6d43604af82c
[2/9] ACPI: NUMA: remove redundant numa_nodes_parsed node_set()
      commit: 7cbdade40fb8f440c13ccd7a02d104bf32285187
[3/9] of/numa: remove redundant numa_nodes_parsed node_set()
      commit: 3b1e5d902dfa832e4b175cb1f5a000236d45ceb5
[4/9] x86/numa: remove redundant numa_nodes_parsed node_set()
      commit: 63fa742bae02f0d2ffe95ff540a51837815abc5c
[5/9] arch_numa: remove redundant numa_nodes_parsed node_set()
      commit: 8b9cecbdc78c5a6cfaaf3b00ce7ebe05cf5417e7
[6/9] LoongArch: remove redundant numa_nodes_parsed node_set()
      commit: 3aeac07c5b1c3399487f4b38182f8cfbc3dbbd53
[7/9] mm: numa_memblks: remove redundant numa_nodemask_from_meminfo()
      commit: a9bafc1832d2db97813069823821ed333b8ecda6
[8/9] arch_numa: remove redundant node_possible_map assignment
      commit: f5a77a50a14dffb659ee8f550c824f8280e37fce
[9/9] mm: numa_memblks: use numa_add_reserved_memblk() in numa_cleanup_meminfo()
      commit: e55424c84afd48aa2f0f761ae0c006128ef541cf

tree: https://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock
branch: numa_memblks-redundant-work

--
Sincerely yours,
Mike.