Re: [PATCH 10/17] jbd2: replace __get_free_pages() with kmalloc()

[Jan Kara]

On Sat 23-05-26 20:54:22, Mike Rapoport (Microsoft) wrote:
> jbd2_alloc() falls back from kmem_cache_alloc() to __get_free_pages() for
> allocations larger than PAGE_SIZE.
> But kmalloc() can handle such cases with essentially the same fallback.
> 
> Replace use of __get_free_pages() with kmalloc() and simplify
> jbd2_free() as both kmem_cache_alloc() and kmalloc() allocations can be
> freed with kfree().
> 
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@xxxxxxx>

I'll just note that we allocate here fs block size large buffer so the same
kind of allocator as we use for folios would be even better. But that's a
different cleanup I guess.

								Honza

> ---
>  fs/jbd2/journal.c | 7 ++-----
>  1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 4f397fcdb13c..1137b471e490 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -2784,7 +2784,7 @@ void *jbd2_alloc(size_t size, gfp_t flags)
>  	if (size < PAGE_SIZE)
>  		ptr = kmem_cache_alloc(get_slab(size), flags);
>  	else
> -		ptr = (void *)__get_free_pages(flags, get_order(size));
> +		ptr = kmalloc(size, flags);
>  
>  	/* Check alignment; SLUB has gotten this wrong in the past,
>  	 * and this can lead to user data corruption! */
> @@ -2795,10 +2795,7 @@ void *jbd2_alloc(size_t size, gfp_t flags)
>  
>  void jbd2_free(void *ptr, size_t size)
>  {
> -	if (size < PAGE_SIZE)
> -		kmem_cache_free(get_slab(size), ptr);
> -	else
> -		free_pages((unsigned long)ptr, get_order(size));
> +	kfree(ptr);
>  };
>  
>  /*
> 
> -- 
> 2.53.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR