Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 1 Oct 2020 12:19:57 -0700 | Subject | Re: Linux 5.9-rc7 / VmallocTotal wrongly reported |
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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?
On Wed, Sep 30, 2020 at 11:55 PM Bastian Bittorf <bb@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
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