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Date:   Thu, 9 Sep 2021 09:48:49 +0000
From:   Huang Shijie <shijie@os.amperecomputing.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
        jlayton@kernel.org, bfields@fieldses.org,
        torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org,
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        song.bao.hua@hisilicon.com, patches@amperecomputing.com,
        zwang@amperecomputing.com
Subject: Re: [RFC PATCH] fs/exec: Add the support for ELF program's NUMA
 replication
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On Mon, Sep 06, 2021 at 01:09:22PM +0100, Matthew Wilcox wrote:
> On Mon, Sep 06, 2021 at 04:16:13PM +0000, Huang Shijie wrote:
> > This patch adds AT_NUMA_REPLICATION for execveat().
> > 
> > If this flag is set, the kernel will trigger COW(copy on write)
> > on the mmapped ELF binary. So the program will have a copied-page
> > on its NUMA node, even if the original page in page cache is
> > on other NUMA nodes.
> 
> This does absolutely nothing for programs which run on multiple NUMA
> nodes at the same time.
Yes. Not suit for that case (Mysql database..).

> 
> Also, I dislike the abuse of the term "COW" for this.  It's COF --
> Copy On Fault.
Maybe it is better to add new flags "NUMA_REPLICATION" in mmap(). :)

Thanks
Huang Shijie