> On Feb 22, 2022, at 4:10 AM, Vasily Averin <vvs@xxxxxxxxxxxxx> wrote: > > On 22.02.2022 13:23, Hyeonggon Yoo wrote: >>> On Tue, Feb 22, 2022 at 12:22:02PM +0300, Vasily Averin wrote: >>> Dear all, >>> >>> I've found that /proc/slabinfo shows inadequate numbers of in-use slab objects. >>> it assumes that all objects stored in cpu caches are always 100% in use. > >>> Is it a bug or perhaps a well-known feature that I missed? >> This is not a bug.. > > Thank you for explanation, > I think it would be useful to document this somewhere. (Documnetation? man slabinfo ?) > Also I would like to know is it some (fast) way to get real numbers in userspace ? > crash is too fat for this task. > Do you know perhaps some other userspace utility or may be systemtap/drgn script? Btw, implementing fast slab counters independent from the sl*b implementation and the physical layout of data might be an interesting idea. Currently /proc/slabinfo is often confusing because of the slab merging. It’s particularly true when someone tries to compare memory usage on two different kernel versions, for example: the set of slab caches might look very different depending on subtle changes in object sizes and the caches merging outcome.
