Re: [PATCH] mm/vmstat: Reduce zone lock hold time when reading /proc/pagetypeinfo

[Qian Cai]

> On Oct 23, 2019, at 5:56 AM, Mel Gorman <mgorman@xxxxxxx> wrote:
> 
> Again, the cost is when reading a proc file. From what Andrew said,
> the lock is necessary to safely walk the list but if anything. I would
> be ok with limiting the length of the walk but honestly, I would also
> be ok with simply deleting the proc file. The utility for debugging a
> problem with it is limited now (it was more important when fragmentation
> avoidance was first introduced) and there is little an admin can do with
> the information. I can't remember the last time I asked for the contents
> of the file when trying to debug a problem. There is a possibility that
> someone will complain but I'm not aware of any utility that reads the
> information and does something useful with it. In the unlikely event
> something breaks, the file can be re-added with a limited walk.

Agree. It is better to remove this file all together in linux-next first for a while to see if anyone complains loudly.