On 7/2/19 5:33 PM, Andrew Morton wrote: > On Tue, 2 Jul 2019 16:44:24 -0400 Waiman Long <longman@xxxxxxxxxx> wrote: > >> On 7/2/19 4:03 PM, Andrew Morton wrote: >>> On Tue, 2 Jul 2019 14:37:30 -0400 Waiman Long <longman@xxxxxxxxxx> wrote: >>> >>>> Currently, a value of '1" is written to /sys/kernel/slab/<slab>/shrink >>>> file to shrink the slab by flushing all the per-cpu slabs and free >>>> slabs in partial lists. This applies only to the root caches, though. >>>> >>>> Extends this capability by shrinking all the child memcg caches and >>>> the root cache when a value of '2' is written to the shrink sysfs file. >>> Why? >>> >>> Please fully describe the value of the proposed feature to or users. >>> Always. >> Sure. Essentially, the sysfs shrink interface is not complete. It allows >> the root cache to be shrunk, but not any of the memcg caches. > But that doesn't describe anything of value. Who wants to use this, > and why? How will it be used? What are the use-cases? > For me, the primary motivation of posting this patch is to have a way to make the number of active objects reported in /proc/slabinfo more accurately reflect the number of objects that are actually being used by the kernel. When measuring changes in slab objects consumption between successive run of a certain workload, I can more easily see the amount of increase. Without that, the data will have much more noise and it will be harder to see a pattern. Cheers, Longman
