On 07/03/2018 05:18 AM, Andrew Morton wrote: > On Mon, 2 Jul 2018 12:34:00 -0700 Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >> On Sun, Jul 1, 2018 at 10:52 PM Waiman Long <longman@xxxxxxxxxx> wrote: >>> A rogue application can potentially create a large number of negative >>> dentries in the system consuming most of the memory available if it >>> is not under the direct control of a memory controller that enforce >>> kernel memory limit. >> I certainly don't mind the patch series, but I would like it to be >> accompanied with some actual example numbers, just to make it all a >> bit more concrete. >> >> Maybe even performance numbers showing "look, I've filled the dentry >> lists with nasty negative dentries, now it's all slower because we >> walk those less interesting entries". >> > (Please cc linux-mm@xxxxxxxxx on this work) > > Yup. The description of the user-visible impact of current behavior is > far too vague. > > In the [5/6] changelog it is mentioned that a large number of -ve > dentries can lead to oom-killings. This sounds bad - -ve dentries > should be trivially reclaimable and we shouldn't be oom-killing in such > a situation. The OOM situation was observed in an older distro kernel. It may not be the case with the upstream kernel. I will double check that. Cheers, Longman
