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From: Stephen Hemminger <stephen@networkplumber.org>
To: "Xie, Huawei" <huawei.xie@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: Sun, 22 Nov 2015 22:52:20 -0800	[thread overview]
Message-ID: <20151122225220.1fd15ba8@xeon-e3> (raw)
In-Reply-To: <C37D651A908B024F974696C65296B57B4B1A701B@SHSMSX101.ccr.corp.intel.com>

On Mon, 23 Nov 2015 05:05:21 +0000
"Xie, Huawei" <huawei.xie@intel.com> wrote:

> On 11/23/2015 12:07 PM, Stephen Hemminger wrote:
> > On Mon, 23 Nov 2015 03:46:31 +0000
> > "Xie, Huawei" <huawei.xie@intel.com> wrote:
> >
> >>> Why cannot we rely on the kernel zeroing the memory ?
> >>> If that behavior were to change, then we can zero out the memory
> >>> ourselves.  
> >> It is undocumented kernel behavior. My opinion is if not a big burden,
> >> zero out the needed memory ourselves, otherwise resort to this kernel
> >> behavior.
> > Really, I think it is more an oversight of missing documentation,
> > the kernel has always (and will continue) to zero out memory that is given
> > to a process. If it didn't it would be a massive security hole.
> Agree. I believe this behavior will not change in future. For the
> security issue, kernel could also set all bits like to 1. Just wonder if
> this is best practice and whether there are other user space programs
> rely on this behavior.
> 

Glibc almost certainly depends on this, because heap is grown by mmaping addtional
memory.

  reply	other threads:[~2015-11-23  6:52 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
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 [this message]
2015-11-25 18:24                   ` Xie, Huawei
2015-12-24  8:34 ` [dpdk-dev] [RFC PATCH 0/2] Reduce DPDK initialization time Qiu, Michael

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