Re: [RFC PATCH] fs/exec: Add the support for ELF program's NUMA replication

From: Huang Shijie
Date: Wed Sep 08 2021 - 21:50:33 EST

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(). :)

Huang Shijie