Re: [PATCH 1/6] s390/con3270: replace __get_free_page() with kmalloc()

[Heiko Carstens <hca@linux.ibm.com>]

On Thu, May 28, 2026 at 10:09:49AM +0300, Mike Rapoport (Microsoft) wrote:
> con3270_alloc_view() allocates a staging buffer used to assemble
> 3270 datastream content before it is copied into channel program
> requests.
> 
> This buffer can be allocated with kmalloc() as there's nothing special
> about it to go directly to the page allocator.
> 
> kmalloc() provides a better API that does not require ugly casts and
> kfree() does not need to know the size of the freed object.
> 
> Performance difference between kmalloc() and __get_free_pages() is not
> measurable as both allocators take an object/page from a per-CPU list for
> fast path allocations.
> 
> For the slow path the performance is anyway determined by the amount of
> reclaim involved rather than by what allocator is used.
> 
> Replace use of __get_free_page() with kmalloc() and free_page() with
> kfree().
> 
> Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
>  drivers/s390/char/con3270.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Reviewed-by: Heiko Carstens <hca@linux.ibm.com>