From: Mel Gorman <mgorman@techsingularity.net>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: willy@infradead.org, mhocko@suse.com, linux-mm@kvack.org,
akpm@linux-foundation.org
Subject: Re: [RFC] put page to pcp->lists[] tail if it is not on the same node
Date: Fri, 19 Oct 2018 09:38:18 +0100 [thread overview]
Message-ID: <20181019083818.GQ5819@techsingularity.net> (raw)
In-Reply-To: <20181019043303.s5axhjfb2v2lzsr3@master>
On Fri, Oct 19, 2018 at 04:33:03AM +0000, Wei Yang wrote:
> node
> Reply-To: Wei Yang <richard.weiyang@gmail.com>
>
> Masters,
>
> During the code reading, I pop up this idea.
>
> In case we put some intelegence of NUMA node to pcp->lists[], we may
> get a better performance.
>
Why?
> The idea is simple:
>
> Put page on other nodes to the tail of pcp->lists[], because we
> allocate from head and free from tail.
>
Pages from remote nodes are not placed on local lists. Even in the slab
context, such objects are placed on alien caches which have special
handling.
> Since my desktop just has one numa node, I couldn't test the effect.
I suspect it would eventually cause a crash or at least weirdness as the
page zone ids would not match due to different nodes.
> Sorry for sending this without a real justification. Hope this will not
> make you uncomfortable. I would be very glad if you suggest some
> verifications that I could do.
>
> Below is my testing patch, look forward your comments.
>
I commend you trying to understand how the page allocator works but I
suggest you take a step back, pick a workload that is of interest and
profile it to see where hot spots are that may pinpoint where an
improvement can be made.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2018-10-19 8:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-19 4:33 [RFC] put page to pcp->lists[] tail if it is not on the same node Wei Yang
2018-10-19 8:38 ` Mel Gorman [this message]
2018-10-20 0:54 ` Wei Yang
2018-10-20 16:33 ` Wei Yang
2018-10-21 2:36 ` Wei Yang
2018-10-21 12:12 ` Mel Gorman
2018-10-22 1:24 ` Wei Yang
2018-10-19 13:43 ` Vlastimil Babka
2018-10-20 1:38 ` Wei Yang
2018-10-20 16:10 ` Wei Yang
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