From: Huang Shijie via Libc-alpha <libc-alpha@sourceware.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: song.bao.hua@hisilicon.com,
Huang Shijie via Libc-alpha <libc-alpha@sourceware.org>,
zwang@amperecomputing.com, willy@infradead.org,
linux-mm@kvack.org, viro@zeniv.linux.org.uk,
patches@amperecomputing.com, torvalds@linux-foundation.org,
akpm@linux-foundation.org
Subject: Re: [PATCH] Add LD_NUMA_REPLICATION for glibc
Date: Fri, 3 Sep 2021 15:15:35 +0000 [thread overview]
Message-ID: <YTI8FyHQVZ+o1ZGP@hsj> (raw)
In-Reply-To: <87bl5a6ul2.fsf@oldenburg.str.redhat.com>
On Fri, Sep 03, 2021 at 08:28:57AM +0200, Florian Weimer wrote:
> * Huang Shijie via Libc-alpha:
>
> > This patch adds LD_NUMA_REPLICATION which influences the linkage of shared libraries at run time.
> >
> > If LD_NUMA_REPLICATION is set for program foo like this:
> > #LD_NUMA_REPLICATION=1 ./foo
> >
> > At the time ld.so mmaps the shared libraries, it will uses
> > mmap(, c->prot | PROT_WRITE, MAP_COPY | MAP_FILE | MAP_POPULATE,)
> > for them, and the mmap will trigger COW(copy on write) for the shared
> > libraries at the NUMA node which the program `foo` runs. After the
> > COW, the foo will have a copy of the shared library segment(mmap
> > covered) which belong to the same NUMA node.
> >
> > So when enable LD_NUMA_REPLICATION, it will consume more memory,
> > but it will reduce the remote-access in NUMA.
>
> I think the kernel could do this in a much better way, avoiding
> duplicating the pages within the same NUMA node.
I think maybe only the per-NUMA-node page cache can avoid it..
>
> The other issue is the temporary RWX mapping, which does not
> interoperate well with some security hardening features.
>
Thanks for the feedback.
I CC more people who may have interesting about this.
Thanks
Huang Shijie
next prev parent reply other threads:[~2021-09-03 7:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-03 12:14 [PATCH] Add LD_NUMA_REPLICATION for glibc Huang Shijie via Libc-alpha
2021-09-03 6:28 ` Florian Weimer via Libc-alpha
2021-09-03 15:15 ` Huang Shijie via Libc-alpha [this message]
2021-09-03 22:16 ` Song Bao Hua (Barry Song) via Libc-alpha
2021-09-06 9:14 ` Huang Shijie via Libc-alpha
2021-09-09 10:19 ` Huang Shijie via Libc-alpha
2021-09-10 11:01 ` Florian Weimer via Libc-alpha
2021-09-13 14:40 ` Huang Shijie via Libc-alpha
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