linux-kernel - Re: [patch 113/131] mm: balance LRU lists based on relative thrashing

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAAmzW4OrmCBQC05E6Kr-pLw3VU=cthzZCpfEzDabhO5vTaq8KA@mail.gmail.com>
Date:   Wed, 10 Jun 2020 14:23:57 +0900
From:   Joonsoo Kim <js1304@...il.com>
To:     Johannes Weiner <hannes@...xchg.org>
Cc:     Alex Shi <alex.shi@...ux.alibaba.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        Linux Memory Management List <linux-mm@...ck.org>,
        Michal Hocko <mhocko@...e.com>,
        김민찬 <minchan@...nel.org>,
        mm-commits@...r.kernel.org, Rik van Riel <riel@...riel.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [patch 113/131] mm: balance LRU lists based on relative thrashing

2020년 6월 9일 (화) 오후 11:46, Johannes Weiner <hannes@...xchg.org>님이 작성:
>
> On Tue, Jun 09, 2020 at 05:15:33PM +0800, Alex Shi wrote:
> >
> >
> > 在 2020/6/4 上午7:03, Andrew Morton 写道:
> > >
> > > +   /* XXX: Move to lru_cache_add() when it supports new vs putback */
> >
> > Hi Hannes,
> >
> > Sorry for a bit lost, would you like to explain a bit more of your idea here?
> >
> > > +   spin_lock_irq(&page_pgdat(page)->lru_lock);
> > > +   lru_note_cost(page);
> > > +   spin_unlock_irq(&page_pgdat(page)->lru_lock);
> > > +
> >
> >
> > What could we see here w/o the lru_lock?
>
> It'll just be part of the existing LRU locking in
> pagevec_lru_move_fn(), when the new pages are added to the LRU in
> batch. See this older patch for example:
>
> https://lore.kernel.org/linux-mm/20160606194836.3624-6-hannes@cmpxchg.org/
>
> I didn't include it in this series to reduce conflict with Joonsoo's
> WIP series that also operates in this area and does something similar:

Thanks!

> https://lkml.org/lkml/2020/4/3/63

I haven't completed the rebase of my series but I guess that referenced patch
"https://lkml.org/lkml/2020/4/3/63" would be removed in the next version.

Before the I/O cost model, a new anonymous page contributes to the LRU reclaim
balance. But, now, a new anonymous page doesn't contributes to the I/O cost
so this adjusting patch would not be needed anymore.

If anyone wants to change this part,
"/* XXX: Move to lru_cache_add() when it supports new vs putback */", feel free
to do it.

Thanks.