Hi,

On Wed, Jan 07, 2026 at 09:57:34AM +0530, Ritesh Harjani wrote:

Mike Rapoport [off-list ref] writes:

quoted

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

Move calculations of zone limits to a dedicated arch_zone_limits_init()
function.

Later MM core will use this function as an architecture specific callback
during nodes and zones initialization and thus there won't be a need to
call free_area_init() from every architecture.

Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
---
 arch/powerpc/mm/mem.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 3ddbfdbfa941..32c496bfab4f 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c

@@ -221,13 +221,23 @@ static int __init mark_nonram_nosave(void)
  * anyway) will take a first dip into ZONE_NORMAL and get otherwise served by
  * ZONE_DMA.
  */
-static unsigned long max_zone_pfns[MAX_NR_ZONES];
+void __init arch_zone_limits_init(unsigned long *max_zone_pfns)
+{
+#ifdef CONFIG_ZONE_DMA
+	max_zone_pfns[ZONE_DMA]	= min(zone_dma_limit, max_low_pfn - 1) + 1;

Hi Mike, 

This doesn't look correct. Isn't the zone_dma_limit value in bytes actually?
Shouldn't it be -

     max_zone_pfns[ZONE_DMA] = min((zone_dma_limit >> PAGE_SHIFT) + 1, max_low_pfn);

You are right, I'll update it for v3. 
 

-ritesh

-- 
Sincerely yours,
Mike.