Re: [PATCH 1/2] CPU, NUMA topology ABIs: clarify the overflow issue of sysfs pagebuf
From: Dave Hansen
Date: Thu Apr 29 2021 - 10:21:21 EST
On 4/29/21 12:03 AM, Tian Tao wrote:
> diff --git a/Documentation/ABI/stable/sysfs-devices-node b/Documentation/ABI/stable/sysfs-devices-node
> index 484fc04..82dfe64 100644
> --- a/Documentation/ABI/stable/sysfs-devices-node
> +++ b/Documentation/ABI/stable/sysfs-devices-node
> @@ -47,7 +47,10 @@ What: /sys/devices/system/node/nodeX/cpulist
> Date: October 2002
> Contact: Linux Memory Management list <linux-mm@xxxxxxxxx>
> - The CPUs associated to the node.
> + The CPUs associated to the node. The format is like 0-3,
> + 8-11, 14,17. maximum size is PAGE_SIZE, so the tail
> + of the string will be trimmed while its size is larger
> + than PAGE_SIZE.
I think it's pretty arguable that truncating output on a real system is
an ABI break. Doing this would make the interface rather useless.
Don't we need a real solution rather than throwing up our hands?
Do we think >PAGE_SIZE data out of a sysfs file is a worse ABI break or