From: Khalid Aziz <khalid.aziz@oracle.com>
To: Dave Hansen <dave.hansen@linux.intel.com>,
Rob Gardner <rob.gardner@oracle.com>,
davem@davemloft.net, corbet@lwn.net, arnd@arndb.de,
akpm@linux-foundation.org
Cc: hpa@zytor.com, viro@zeniv.linux.org.uk, nitin.m.gupta@oracle.com,
chris.hyser@oracle.com, tushar.n.dave@oracle.com,
sowmini.varadhan@oracle.com, mike.kravetz@oracle.com,
adam.buchbinder@gmail.com, minchan@kernel.org, hughd@google.com,
kirill.shutemov@linux.intel.com, keescook@chromium.org,
allen.pais@oracle.com, aryabinin@virtuozzo.com,
atish.patra@oracle.com, joe@perches.com, pmladek@suse.com,
jslaby@suse.cz, cmetcalf@mellanox.com,
paul.gortmaker@windriver.com, mhocko@suse.com,
jmarchan@redhat.com, lstoakes@gmail.com, 0x7f454c46@gmail.com,
vbabka@suse.cz, tglx@linutronix.de, mingo@redhat.com,
dan.j.williams@intel.com, iamjoonsoo.kim@lge.com,
mgorman@techsingularity.net, vdavydov.dev@gmail.com,
hannes@cmpxchg.org, namit@vmware.com, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
linux-arch@vger.kernel.org, x86@kernel.org, linux-mm@kvack.org,
Khalid Aziz <khalid@gonehiking.org>
Subject: Re: [RFC PATCH v3] sparc64: Add support for Application Data Integrity (ADI)
Date: Wed, 4 Jan 2017 16:58:13 -0700 [thread overview]
Message-ID: <ba9c4de2-cec1-1c88-82c9-24a524eb7948@oracle.com> (raw)
In-Reply-To: <2c0502d0-20ef-44ac-db5b-7f651a70b978@linux.intel.com>
On 01/04/2017 04:49 PM, Dave Hansen wrote:
> On 01/04/2017 03:44 PM, Rob Gardner wrote:
>> On 01/04/2017 03:40 PM, Dave Hansen wrote:
>>> On 01/04/2017 03:35 PM, Rob Gardner wrote:
>>>> Tags are not cleared at all when memory is freed, but rather, lazily
>>>> (and automatically) cleared when memory is allocated.
>>> What does "allocated" mean in this context? Physical or virtual? What
>>> does this do, for instance?
>>
>> The first time a virtual page is touched by a process after the malloc,
>> the kernel does clear_user_page() or something similar, which zeroes the
>> memory. At the same time, the memory tags are cleared.
>
> OK, so the tags can't survive a MADV_FREE. That's definitely something
> for apps to understand that use MADV_FREE as a substitute for memset().
> It also means that tags can't be set for physically unallocated memory.
>
> Neither of those are deal killers, but it would be nice to document it.
This can go into the adi.txt doc file.
>
> How does this all work with large pages?
It works with large pages the same way as normal sized pages. The TTE
for a large page also will have the mcd bit set in it and tags are set
and referenced the same way.
--
Khalid
next prev parent reply other threads:[~2017-01-04 23:59 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-04 22:46 [RFC PATCH v3] sparc64: Add support for Application Data Integrity (ADI) Khalid Aziz
2017-01-04 23:27 ` Dave Hansen
2017-01-04 23:35 ` Rob Gardner
2017-01-04 23:40 ` Dave Hansen
2017-01-04 23:44 ` Rob Gardner
2017-01-04 23:49 ` Dave Hansen
2017-01-04 23:56 ` Rob Gardner
2017-01-04 23:58 ` Khalid Aziz [this message]
2017-01-05 0:01 ` Dave Hansen
2017-01-05 0:05 ` Rob Gardner
2017-01-05 0:14 ` Dave Hansen
2017-01-05 0:26 ` Khalid Aziz
2017-01-05 19:22 ` Dave Hansen
2017-01-05 20:30 ` Khalid Aziz
2017-01-06 9:19 ` Michal Hocko
2017-01-06 15:32 ` Khalid Aziz
2017-01-06 15:36 ` Dave Hansen
2017-01-06 16:22 ` Khalid Aziz
2017-01-06 16:25 ` David Miller
2017-01-06 16:55 ` Dave Hansen
2017-01-06 17:02 ` David Miller
2017-01-06 17:10 ` Khalid Aziz
2017-01-06 17:54 ` Rob Gardner
2017-01-06 18:18 ` Khalid Aziz
2017-01-06 18:28 ` Rob Gardner
2017-01-06 17:08 ` Khalid Aziz
2017-01-04 23:43 ` Khalid Aziz
2017-01-04 23:31 ` Dave Hansen
2017-01-04 23:46 ` Khalid Aziz
2017-01-04 23:50 ` Dave Hansen
2017-01-05 9:37 ` Jerome Marchand
2017-01-05 15:13 ` Khalid Aziz
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=ba9c4de2-cec1-1c88-82c9-24a524eb7948@oracle.com \
--to=khalid.aziz@oracle.com \
--cc=0x7f454c46@gmail.com \
--cc=adam.buchbinder@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=allen.pais@oracle.com \
--cc=arnd@arndb.de \
--cc=aryabinin@virtuozzo.com \
--cc=atish.patra@oracle.com \
--cc=chris.hyser@oracle.com \
--cc=cmetcalf@mellanox.com \
--cc=corbet@lwn.net \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=davem@davemloft.net \
--cc=hannes@cmpxchg.org \
--cc=hpa@zytor.com \
--cc=hughd@google.com \
--cc=iamjoonsoo.kim@lge.com \
--cc=jmarchan@redhat.com \
--cc=joe@perches.com \
--cc=jslaby@suse.cz \
--cc=keescook@chromium.org \
--cc=khalid@gonehiking.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lstoakes@gmail.com \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=mike.kravetz@oracle.com \
--cc=minchan@kernel.org \
--cc=mingo@redhat.com \
--cc=namit@vmware.com \
--cc=nitin.m.gupta@oracle.com \
--cc=paul.gortmaker@windriver.com \
--cc=pmladek@suse.com \
--cc=rob.gardner@oracle.com \
--cc=sowmini.varadhan@oracle.com \
--cc=sparclinux@vger.kernel.org \
--cc=tglx@linutronix.de \
--cc=tushar.n.dave@oracle.com \
--cc=vbabka@suse.cz \
--cc=vdavydov.dev@gmail.com \
--cc=viro@zeniv.linux.org.uk \
--cc=x86@kernel.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).