From: Alexander Duyck <alexander.duyck@gmail.com>
To: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
kbuild test robot <lkp@intel.com>,
Rong Chen <rong.a.chen@intel.com>,
Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Hugh Dickins <hughd@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Daniel Jordan <daniel.m.jordan@oracle.com>,
linux-mm <linux-mm@kvack.org>,
Shakeel Butt <shakeelb@google.com>,
Matthew Wilcox <willy@infradead.org>,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
cgroups@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Wei Yang <richard.weiyang@gmail.com>,
Mel Gorman <mgorman@techsingularity.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [RFC PATCH v2 4/5] mm: Split release_pages work into 3 passes
Date: Thu, 20 Aug 2020 07:13:30 -0700 [thread overview]
Message-ID: <CAKgT0UdmKpn3x_=F4E-u+mCf75hu4Bu0O0dyds4mHq93G6wJVA@mail.gmail.com> (raw)
In-Reply-To: <a88eef1b-242d-78c6-fecb-35ea00cd739b@linux.alibaba.com>
On Thu, Aug 20, 2020 at 2:51 AM Alex Shi <alex.shi@linux.alibaba.com> wrote:
>
>
>
> 在 2020/8/19 下午10:57, Alexander Duyck 写道:
> >>> lruvec = relock_page_lruvec_irqsave(page, lruvec, &flags);
> >> the lock bounce is better with the patch, would you like to do further
> >> like using add_lruvecs to reduce bounce more?
> >>
> >> Thanks
> >> Alex
> > I'm not sure how much doing something like that would add. In my case
> > I had a very specific issue that this is addressing which is the fact
> > that every compound page was taking the LRU lock and zone lock
> > separately. With this patch that is reduced to one LRU lock per 15
> > pages and then the zone lock per page. By adding or sorting pages by
> > lruvec I am not sure there will be much benefit as I am not certain
> > how often we will end up with pages being interleaved between multiple
> > lruvecs. In addition as I am limiting the quantity to a pagevec which
> > limits the pages to 15 I am not sure there will be much benefit to be
> > seen for sorting the pages beforehand.
> >
>
> the relock will unlock and get another lock again, the cost in that, the 2nd
> lock need to wait for fairness for concurrency lruvec locking.
> If we can do sort before, we should remove the fairness waiting here. Of course,
> perf result depends on scenarios.
Agreed. The question is in how many scenarios are you going to have
pages interleaved between more than one lruvec? I suspect in most
cases you should only have one lruvec for all the pages being
processed in a single pagevec.
next prev parent reply other threads:[~2020-08-20 14:13 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-19 4:26 [RFC PATCH v2 0/5] Minor cleanups and performance optimizations for LRU rework Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 1/5] mm: Identify compound pages sooner in isolate_migratepages_block Alexander Duyck
2020-08-19 7:48 ` Alex Shi
2020-08-19 11:43 ` Matthew Wilcox
2020-08-19 14:48 ` Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 2/5] mm: Drop use of test_and_set_skip in favor of just setting skip Alexander Duyck
2020-08-19 7:50 ` Alex Shi
2020-08-19 4:27 ` [RFC PATCH v2 3/5] mm: Add explicit page decrement in exception path for isolate_lru_pages Alexander Duyck
2020-08-19 7:50 ` Alex Shi
2020-08-19 14:52 ` Alexander Duyck
2020-08-19 4:27 ` [RFC PATCH v2 4/5] mm: Split release_pages work into 3 passes Alexander Duyck
2020-08-19 7:53 ` Alex Shi
2020-08-19 14:57 ` Alexander Duyck
2020-08-20 9:49 ` Alex Shi
2020-08-20 14:13 ` Alexander Duyck [this message]
2020-08-19 4:27 ` [RFC PATCH v2 5/5] mm: Split move_pages_to_lru into 3 separate passes Alexander Duyck
2020-08-19 7:56 ` Alex Shi
2020-08-19 14:42 ` Alexander Duyck
2020-08-20 9:56 ` Alex Shi
2020-08-20 17:15 ` Alexander Duyck
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