Re: [PATCH] z3fold: make pages_nr atomic

[Andrew Morton]

On Thu, 3 Nov 2016 22:24:07 +0100 Vitaly Wool <vitalywool@xxxxxxxxx> wrote:

> On Thu, Nov 3, 2016 at 10:14 PM, Andrew Morton
> <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Thu, 3 Nov 2016 22:00:58 +0100 Vitaly Wool <vitalywool@xxxxxxxxx> wrote:
> >
> >> This patch converts pages_nr per-pool counter to atomic64_t.
> >
> > Which is slower.
> >
> > Presumably there is a reason for making this change.  This reason
> > should be described in the changelog.
> 
> The reason [which I thought was somewhat obvious :) ] is that there
> won't be a need to take a per-pool lock to read or modify that
> counter.

But the patch didn't change the locking.  And as far as I can tell,
neither does "z3fold: extend compaction function".