DPDK patches and discussions
 help / color / mirror / Atom feed
From: Tiwei Bie <tiwei.bie@intel.com>
To: Bruce Richardson <bruce.richardson@intel.com>
Cc: dev@dpdk.org, stable@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] eal/bsd: don't zero the pages during mmap in contigmem
Date: Mon, 8 May 2017 17:13:34 +0800	[thread overview]
Message-ID: <20170508091334.GB11935@debian> (raw)
In-Reply-To: <20170508085357.GA47408@bricha3-MOBL3.ger.corp.intel.com>

On Mon, May 08, 2017 at 09:53:57AM +0100, Bruce Richardson wrote:
> On Mon, May 08, 2017 at 08:09:16AM +0000, Tiwei Bie wrote:
> > Don't zero the pages during mmap in contigmem. Instead, zero the
> > pages after mmap in primary process. Otherwise, the multi-process
> > support will be broken, as the pages will be zeroed when secondary
> > processes map the memory.
> > 
> > Fixes: 82f931805506 ("contigmem: zero all pages during mmap")
> > Cc: stable@dpdk.org
> > 
> > Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> > ---
> I agree there is a problem here, but I'm not sure about the solution to
> it. I still think that the kernel should zero the pages before they get
> given to userspace. Is there any way to keep that working e.g
> 
> * have them zeroed on mmap only when they are not already mmaped into
>   another process?
> * have them zeroed on init, and again on unmap by the last process to
>   have them mapped?
> 

I think it's the simplest way to fix it in userspace, so I just did it.
I'd like to fix it in kernel if you also prefer this.

Best regards,
Tiwei Bie

      reply	other threads:[~2017-05-08  9:11 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-08  8:09 Tiwei Bie
2017-05-08  8:53 ` Bruce Richardson
2017-05-08  9:13   ` Tiwei Bie [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20170508091334.GB11935@debian \
    --to=tiwei.bie@intel.com \
    --cc=bruce.richardson@intel.com \
    --cc=dev@dpdk.org \
    --cc=stable@dpdk.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).