Re: [PATCH] mm/vmscan: fix infinite loop in drop_slab_node

[Chris Down]

Vlastimil Babka writes:
> On 9/8/20 5:09 PM, Chris Down wrote:
> > drop_caches by its very nature can be extremely performance intensive -- if
> > someone wants to abort after trying too long, they can just send a
> > TASK_KILLABLE signal, no? If exiting the loop and returning to usermode doesn't
> > reliably work when doing that, then _that's_ something to improve, but this
> > looks premature to me until that's demonstrated not to work.
>
> Hm there might be existings scripts (even though I dislike those) running
> drop_caches periodically, and they are currently not set up to be killed, so one
> day it might surprise someone. Dropping should be a one-time event, not a
> continual reclaim.

Sure, but these scripts can send it to their child themselves instead of using 
WCE, no? As far as I know, that's the already supported way to abort 
drop_caches-induced reclaim.