On Thu, Oct 01, 2020 at 12:19:57PM -0700, Linus Torvalds wrote: > Adding Vlastimil, Roman and the kernel mailing list to the cc. > > Vlastimil, Roman - this looks like a slab regression. And while others > have touched slab in this merge window, you guys did so more than > most.. Comments?
Thank you, Linus! I think it's a regression from my slab controller changes, and I have a theory. Bastian, can you, please, share your config? I will come up with a patch soon. Thanks! > > On Wed, Sep 30, 2020 at 11:55 PM Bastian Bittorf <b...@npl.de> wrote: > > > > Since 5.9-rc1 i can see false values, booting with qemu (128mb RAM): > > > > / # free > > total used free shared buff/cache > > available > > Mem: 122176 18014398506028288 114848 0 3461024 > > 3568096 > > that looks like a negative 64-bit number shifted down by 10 bits (bytes -> > kB). > > > / # cat /proc/meminfo | grep ^V > > VmallocTotal: 34359738367 kB > > .. but this part is normal. VMALLOC_TOTAL is the VM space for vmalloc > areas, and it's large on a 64-bit machine. > > And afaik, it hasn't changed in a long time. > > So I think there's something else confusing 'free'. > > I think it's this: > > > / # cat /proc/meminfo > > MemAvailable: 3617184 kB > .. > > Slab: 10321920 kB > > SReclaimable: 3506176 kB > > SUnreclaim: 6815744 kB > > because those slab reclaimable/unreclaimable numbers look completely > bogus. You have more unreclaimable slab space than you have memory. > > Hmm. I'm not seeing anything similar. And your config looks sane, with > the main difference I see wrt SLAB being that you have > > # CONFIG_SLAB_MERGE_DEFAULT is not set > > but there's nothing wrong with that either. > > It would be lovely if you could bisect it, but maybe Vlastimil or > Roman will go "Ahh, obviously.." > > Linus
