Re: [PATCH] mm, hwpoison: Add comment describing when to add new cases

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

On Tue, Apr 21, 2015 at 11:11:30AM -0700, Andi Kleen wrote:
> From: Andi Kleen <ak@linux.intel.com>
> 
> Here's another comment fix for hwpoison.
> 
> It describes the "guiding principle" on when to add new
> memory error recovery code.
> 
> Signed-off-by: Andi Kleen <ak@linux.intel.com>

Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

> ---
>  mm/memory-failure.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 25c2054..d553993 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -20,6 +20,13 @@
>   * this code has to be extremely careful. Generally it tries to use 
>   * normal locking rules, as in get the standard locks, even if that means 
>   * the error handling takes potentially a long time.
> + *
> + * It can be very tempting to add handling for obscure cases here.
> + * In general any code for handling new cases should only be added if:
> + * - You know how to test it.
> + * - You have a test that can be added to mce-test
> + * - The case actually shows up as a frequent (top 10) page state in
> + *   tools/vm/page-types when running a real workload.
>   * 
>   * There are several operations here with exponential complexity because
>   * of unsuitable VM data structures. For example the operation to map back 
> -- 
> 1.9.3
> 
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>