Re: [PATCH v4 3/9] mm/lru: replace pgdat lru_lock with lruvec lock

[Shakeel Butt]

On Tue, Nov 19, 2019 at 4:24 AM Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> wrote:
>
> This patchset move lru_lock into lruvec, give a lru_lock for each of
> lruvec, thus bring a lru_lock for each of memcg per node.
>
> This is the main patch to replace per node lru_lock with per memcg
> lruvec lock.
>
> We introduce function lock_page_lruvec, it's same as vanilla pgdat lock
> when memory cgroup unset, w/o memcg, the function will keep repin the
> lruvec's lock to guard from page->mem_cgroup changes in page
> migrations between memcgs. (Thanks Hugh Dickins and Konstantin
> Khlebnikov reminder on this. Than the core logical is same as their
> previous patchs)
>
> According to Daniel Jordan's suggestion, I run 64 'dd' with on 32
> containers on my 2s* 8 core * HT box with the modefied case:
>   https://git.kernel.org/pub/scm/linux/kernel/git/wfg/vm-scalability.git/tree/case-lru-file-readtwice
>
> With this and later patches, the dd performance is 144MB/s, the vanilla
> kernel performance is 123MB/s. 17% performance increased.
>
> Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxxxx>
> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Roman Gushchin <guro@xxxxxx>
> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
> Cc: Chris Down <chris@xxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>
> Cc: Qian Cai <cai@xxxxxx>
> Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: "JÃrÃme Glisse" <jglisse@xxxxxxxxxx>
> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
> Cc: swkhack <swkhack@xxxxxxxxx>
> Cc: "Potyra, Stefan" <Stefan.Potyra@xxxxxxxxxxxxxx>
> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
> Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
> Cc: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> Cc: Jason Gunthorpe <jgg@xxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab+samsung@xxxxxxxxxx>
> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
> Cc: Peng Fan <peng.fan@xxxxxxx>
> Cc: Nikolay Borisov <nborisov@xxxxxxxx>
> Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
> Cc: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> Cc: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Tejun Heo <tj@xxxxxxxxxx>
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-mm@xxxxxxxxx
> Cc: cgroups@xxxxxxxxxxxxxxx

This patch (and series) still have unsafe accesses to lruvec.

Alex, I was hoping that you would drop this series in favor of Hugh's
patches. Anyways I will post Hugh patches for review to be considered
for 5.6. I will run a couple of performance experiments.

Shakeel