Re: [PATCH v18 00/32] per memcg lru_lock

[Michal Hocko]

On Mon 24-08-20 11:42:04, Andrew Morton wrote:
> On Mon, 24 Aug 2020 20:54:33 +0800 Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> wrote:
> 
> > The new version which bases on v5.9-rc2. The first 6 patches was picked into
> > linux-mm, and add patch 25-32 that do some further post optimization.
> 
> 32 patches, version 18.  That's quite heroic.  I'm unsure whether I
> should merge it up at this point - what do people think?

This really needs a proper review. Unfortunately
: 24 files changed, 646 insertions(+), 443 deletions(-)
is quite an undertaking to review as well. Especially in a tricky code
which is full of surprises.

I do agree that per memcg locking looks like a nice feature but I do not
see any pressing reason to merge it ASAP. The cover letter doesn't
really describe any pressing usecase that cannot really live without
this being merged.

I am fully aware of my dept to review but I simply cannot find enough
time to sit on it and think it through to have a meaningful feedback at
this moment.

> > Following Daniel Jordan's suggestion, I have run 208 'dd' with on 104
> > containers on a 2s * 26cores * HT box with a modefied case:
> > https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice
> > With this patchset, the readtwice performance increased about 80%
> > in concurrent containers.
> 
> That's rather a slight amount of performance testing for a huge
> performance patchset!  Is more detailed testing planned?

Agreed! This needs much better testing coverage.

-- 
Michal Hocko
SUSE Labs