Re: [PATCH] mm: Drop "PFNs busy" printk in an expected path.

From: Michal Hocko
Date: Thu Dec 29 2016 - 04:13:11 EST


This has been already brought up
http://lkml.kernel.org/r/20161130092239.GD18437@xxxxxxxxxxxxxx and there
was a proposed patch for that which ratelimited the output
http://lkml.kernel.org/r/20161130132848.GG18432@xxxxxxxxxxxxxx resp.
http://lkml.kernel.org/r/robbat2-20161130T195244-998539995Z@xxxxxxxxxxxxxxxxxx

then the email thread just died out because the issue turned out to be a
configuration issue. Michal indicated that the message might be useful
so dropping it completely seems like a bad idea. I do agree that
something has to be done about that though. Can we reconsider the
ratelimit thing?

On Wed 28-12-16 18:31:31, Eric Anholt wrote:
> For CMA allocations, we expect to occasionally hit this error path, at
> which point CMA will retry. Given that, we shouldn't be spamming
> dmesg about it.
>
> The Raspberry Pi graphics driver does frequent CMA allocations, and
> during regression testing this printk was sometimes occurring 100s of
> times per second.
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
> Cc: linux-stable <stable@xxxxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 6de9440e3ae2..bea7204c14a5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7289,8 +7289,6 @@ int alloc_contig_range(unsigned long start, unsigned long end,
>
> /* Make sure the range is really isolated. */
> if (test_pages_isolated(outer_start, end, false)) {
> - pr_info("%s: [%lx, %lx) PFNs busy\n",
> - __func__, outer_start, end);
> ret = -EBUSY;
> goto done;
> }
> --
> 2.11.0
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@xxxxxxxxxx For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>

--
Michal Hocko
SUSE Labs