Re: [RFC PATCH v3 0/7] slub: Delay freezing of CPU partial slabs

[Christoph Lameter]

On Tue, 31 Oct 2023, Chengming Zhou wrote:

> The current scheme (which this series implemented) is:
>
> - node partial slabs: PG_Workingset (set or clear with per-node list_lock protection)
> - cpu partial slabs: !PG_Workingset

And then the frozen flag needs to be set. Otherwise slab_free() would 
conclude it is on a partial list?

> - cpu slabs: !PG_Workingset && frozen (set or clear using cmpxchg together with freelist)



> - full slabs: !PG_Workingset

And frozen is clear? Otherwise it is the same as a cpu partial slab.

> As Vlastimil noted, it's possible to drop "frozen" bit for cpu slabs, but
> we keep it for performance, since we don't need to grab node list_lock to
> check whether PG_Workingset is set or not if the "frozen" bit is set.
>
> Thanks!