DPDK patches and discussions
 help / color / mirror / Atom feed
From: Stephen Hemminger <stephen@networkplumber.org>
To: "Richardson, Bruce" <bruce.richardson@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove	unnecessary hugepage zero-filling
Date: Wed, 18 Nov 2015 11:09:06 -0800	[thread overview]
Message-ID: <20151118110906.3e0b3dcd@samsung9> (raw)
In-Reply-To: <59AF69C657FD0841A61C55336867B5B035985B24@IRSMSX103.ger.corp.intel.com>

On Wed, 18 Nov 2015 16:13:32 +0000
"Richardson, Bruce" <bruce.richardson@intel.com> wrote:

> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen Hemminger
> > Sent: Wednesday, November 18, 2015 4:00 PM
> > To: Xie, Huawei <huawei.xie@intel.com>
> > Cc: dev@dpdk.org
> > Subject: Re: [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove unnecessary
> > hugepage zero-filling
> > 
> > On Wed, 18 Nov 2015 12:07:54 +0000
> > "Xie, Huawei" <huawei.xie@intel.com> wrote:
> > 
> > > >>> The kernel fills new allocated (huge) pages with zeros.
> > > >>> DPDK just has to touch the pages to trigger the allocation.
> > > I think we shouldn't reply on the assumption that kernel has zeroed
> > > the memory. Kernel zeroes the memory mostly to avoid information
> > > leakage.It could also achieve this by setting each bit to 1.
> > > What we indeed need to check is later DPDK initialization code doesn't
> > > assume the memory has been zeroed. Otherwise zero only that part of
> > > the memory. Does this makes sense?
> > 
> > If all new pages are zero, why does DPDK have to pre-touch the pages at
> > all?
> 
> The pages won't actually be mapped into the processes address space until accessed. 
> 
> /Bruce

Isn't that what mmap MAP_POPULATE flag (not currently used) will do.

  reply	other threads:[~2015-11-18 19:09 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-18  3:27 [dpdk-dev] [RFC PATCH 0/2] Reduce DPDK initialization time Zhihong Wang
2015-11-18  3:27 ` [dpdk-dev] [RFC PATCH 1/2] lib/librte_eal: Reduce timer " Zhihong Wang
2015-11-18  3:27 ` [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove unnecessary hugepage zero-filling Zhihong Wang
2015-11-18 10:39   ` Mcnamara, John
2015-11-18 10:44     ` Wang, Zhihong
2015-11-18 12:07       ` Xie, Huawei
2015-11-18 16:00         ` Stephen Hemminger
2015-11-18 16:13           ` Richardson, Bruce
2015-11-18 19:09             ` Stephen Hemminger [this message]
2015-11-19  2:15               ` Wang, Zhihong
2015-11-19  6:04                 ` Xie, Huawei
2015-11-19  6:32                   ` Wang, Zhihong
2015-11-19  9:18                     ` Sergio Gonzalez Monroy
2015-11-23  2:54                     ` Xie, Huawei
2015-11-23 10:18                       ` Bruce Richardson
2015-11-20 12:15               ` Bruce Richardson
2015-11-19  3:54         ` Wang, Zhihong
2015-11-19  6:09           ` Xie, Huawei
2015-11-19  9:14         ` Sergio Gonzalez Monroy
2015-11-23  3:46           ` Xie, Huawei
2015-11-23  4:07             ` Stephen Hemminger
2015-11-23  5:05               ` Xie, Huawei
2015-11-23  6:52                 ` Stephen Hemminger
2015-11-25 18:24                   ` Xie, Huawei
2015-12-24  8:34 ` [dpdk-dev] [RFC PATCH 0/2] Reduce DPDK initialization time Qiu, Michael

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=20151118110906.3e0b3dcd@samsung9 \
    --to=stephen@networkplumber.org \
    --cc=bruce.richardson@intel.com \
    --cc=dev@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).