[PATCH] cma: Take __GFP_NOWARN into account in cma_alloc()

[Jaewon Kim]

Hello

2017-10-04 21:54 GMT+09:00 Boris Brezillon <boris.brezillon at free-electrons.com>:
> cma_alloc() unconditionally prints an INFO message when the CMA
> allocation fails. Make this message conditional on the non-presence of
> __GFP_NOWARN in gfp_mask.
>
> Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
> ---
> Hello,
>
> This patch aims at removing INFO messages that are displayed when the
> VC4 driver tries to allocate buffer objects. From the driver perspective
> an allocation failure is acceptable, and the driver can possibly do
> something to make following allocation succeed (like flushing the VC4
> internal cache).
When I made the patch, there was no GFP.
In my opinion, it is a good idea removing log in case of __GFP_NOWARN.
>
> Also, I don't understand why this message is only an INFO message, and
> not a WARN (pr_warn()). Please let me know if you have good reasons to
> keep it as an unconditional pr_info().
Thank to Michal Hocko, I changed to pr_info rather than just printk in
my first patch code.
https://marc.info/?l=linux-mm&m=148300462103801&w=2
I thought it is just info. It can be pr_warn if need.

Thank you
Jaewon Kim
>
> Thanks,
>
> Boris
> ---
>  mm/cma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/cma.c b/mm/cma.c
> index c0da318c020e..022e52bd8370 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -460,7 +460,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align,
>
>         trace_cma_alloc(pfn, page, count, align);
>
> -       if (ret) {
> +       if (ret && !(gfp_mask & __GFP_NOWARN)) {
>                 pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n",
>                         __func__, count, ret);
>                 cma_debug_show_areas(cma);
> --
> 2.11.0
>
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