Re: [PATCH v4 02/14] memblock: add MEMBLOCK_RSRV_KERN flag

[Changyuan Lyu <changyuanl@google.com>]

Hi Mike,

On Thu,  6 Feb 2025 15:27:42 +0200, Mike Rapoport <rppt@kernel.org> wrote:
> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
>
> to denote areas that were reserved for kernel use either directly with
> memblock_reserve_kern() or via memblock allocations.
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
>  include/linux/memblock.h | 16 +++++++++++++++-
>  mm/memblock.c            | 32 ++++++++++++++++++++++++--------
>  2 files changed, 39 insertions(+), 9 deletions(-)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index e79eb6ac516f..65e274550f5d 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> ......
> @@ -116,7 +117,19 @@ int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid,
>  int memblock_add(phys_addr_t base, phys_addr_t size);
>  int memblock_remove(phys_addr_t base, phys_addr_t size);
>  int memblock_phys_free(phys_addr_t base, phys_addr_t size);
> -int memblock_reserve(phys_addr_t base, phys_addr_t size);
> +int __memblock_reserve(phys_addr_t base, phys_addr_t size, int nid,
> +		       enum memblock_flags flags);
> +
> +static __always_inline int memblock_reserve(phys_addr_t base, phys_addr_t size)
> +{
> +	return __memblock_reserve(base, size, NUMA_NO_NODE, 0);

Without this patch `memblock_reserve` eventually calls `memblock_add_range`
with `MAX_NUMNODES`, but with this patch, `memblock_reserve` calls
`memblock_add_range` with `NUMA_NO_NODE`. Is it intended or an
accidental typo? Thanks!

> ......
>
> -int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
> +int __init_memblock __memblock_reserve(phys_addr_t base, phys_addr_t size,
> +				       int nid, enum memblock_flags flags)
>  {
>  	phys_addr_t end = base + size - 1;
>
> -	memblock_dbg("%s: [%pa-%pa] %pS\n", __func__,
> -		     &base, &end, (void *)_RET_IP_);
> +	memblock_dbg("%s: [%pa-%pa] nid=%d flags=%x %pS\n", __func__,
> +		     &base, &end, nid, flags, (void *)_RET_IP_);
>
> -	return memblock_add_range(&memblock.reserved, base, size, MAX_NUMNODES, 0);

Originally `memblock_reserve` calls `memblock_add_range` with `MAX_NUMNODES`,
See my comments above.

Best,
Changyuan