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From: Nicholas Piggin <npiggin@gmail.com>
To: Shijie Huang <shijie@amperemail.onmicrosoft.com>,
	Matthew Wilcox <willy@infradead.org>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, song.bao.hua@hisilicon.com,
	torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
	Frank Wang <zwang@amperecomputing.com>
Subject: Re: Is it possible to implement the per-node page cache for programs/libraries?
Date: Thu, 02 Sep 2021 13:25:36 +1000	[thread overview]
Message-ID: <1630552995.2mupnzoqzs.astroid@bobo.none> (raw)
In-Reply-To: <YS7yjcqA6txFHd99@casper.infradead.org>

Excerpts from Matthew Wilcox's message of September 1, 2021 1:25 pm:
> On Wed, Sep 01, 2021 at 11:07:41AM +0800, Shijie Huang wrote:
>>     In the NUMA, we only have one page cache for each file. For the
>> program/shared libraries, the
>> remote-access delays longer then the  local-access.
>> 
>> So, is it possible to implement the per-node page cache for
>> programs/libraries?
> 
> At this point, we have no way to support text replication within a
> process.  So what you're suggesting (if implemented) would work for
> processes which limit themselves to a single node.  That is, if you
> have a system with CPUs 0-3 on node 0 and CPUs 4-7 on node 1, a process
> which only works on node 0 or only works on node 1 will get text on the
> appropriate node.
> 
> If there's a process which runs on both nodes 0 and 1, there's no support
> for per-node PGDs.  So it will get a mix of pages from nodes 0 and 1,
> and that doesn't necessarily seem like a big win.  I haven't yet dived
> into how hard it would be to make mm->pgd a per-node allocation.
> 
> I have been thinking about this a bit; one of our internal performance
> teams flagged the potential performance win to me a few months ago.
> I don't have a concrete design for text replication yet; there have been
> various attempts over the years, but none were particularly compelling.

What was not compelling about it?

https://lists.openwall.net/linux-kernel/2007/07/27/112

What are the other attempts?

Thanks,
Nick

  parent reply	other threads:[~2021-09-02  3:25 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-01  3:07 Shijie Huang
2021-09-01  3:07 ` Shijie Huang
2021-09-01  2:09 ` Barry Song
2021-09-01  2:09   ` Barry Song
2021-09-01  3:25 ` Matthew Wilcox
2021-09-01 13:30   ` Huang Shijie
2021-09-01 14:25     ` Huang Shijie
2021-09-01 11:32       ` Matthew Wilcox
2021-09-01 23:58       ` Matthew Wilcox
2021-09-02  0:15         ` Barry Song
2021-09-02  0:15           ` Barry Song
2021-09-02  1:13           ` Linus Torvalds
2021-09-02  1:13             ` Linus Torvalds
2021-09-02 10:16         ` Huang Shijie
2021-09-02  3:25   ` Nicholas Piggin [this message]
2021-09-02 10:17     ` Matthew Wilcox
2021-09-03  7:10       ` Nicholas Piggin
2021-09-03 19:01         ` Matthew Wilcox
2021-09-03 19:08           ` Linus Torvalds
2021-09-03 19:08             ` Linus Torvalds
2021-09-06  9:56             ` Huang Shijie
2021-09-03 23:42           ` Nicholas Piggin
2021-09-01  4:55 ` Al Viro
2021-09-01 13:10   ` Huang Shijie
2021-09-01 17:24   ` Linus Torvalds
2021-09-01 17:24     ` Linus Torvalds
2021-09-01 17:29     ` Linus Torvalds
2021-09-01 17:29       ` Linus Torvalds
2021-09-01 22:56       ` Barry Song
2021-09-01 22:56         ` Barry Song
2021-09-02 10:12         ` Huang Shijie
2021-09-02 10:08       ` Huang Shijie

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