Re: [PATCH] mm/smaps_rollup: return empty file for kthreads instead of ESRCH

[Alex Xu (Hello71)]

Excerpts from Alexey Dobriyan's message of April 14, 2022 2:55 am:
> Returning ESRCH is better so that programs don't waste time reading and
> closing empty files and instantiating useless inodes.

Yes, except ESRCH is not returned for open, it is returned for read.

> Of course it is different if this patch was sent as response to a regression.

I'm not sure I would classify it as a regression; I don't have an 
existing program which broke, it is a new program which happens to use 
some functionality which worked with a previous kernel. It is 
theoretically possible that some program exists that currently uses 
4.14, and will break if upgraded to 4.19+, but it is also possible that 
some program exists that currently uses 4.19+ and will break if this 
patch is applied.

Cheers,
Alex.