linux-kernel - Re: [RFC] [PATCH v5 0/3] fadvise: support POSIX_FADV

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 12 Feb 2012 23:24:27 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Andrea Righi <andrea@...terlinux.com>,
	Hillf Danton <dhillf@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Minchan Kim <minchan.kim@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Johannes Weiner <jweiner@...hat.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Rik van Riel <riel@...hat.com>,
	Hugh Dickins <hughd@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [RFC] [PATCH v5 0/3] fadvise: support POSIX_FADV_NOREUSE

On Sun, 12 Feb 2012 12:58:34 +0100, Andrea Righi <andrea@...terlinux.com> wrote:
> On Sun, Feb 12, 2012 at 03:16:07PM +0800, Hillf Danton wrote:
> > Hello Andrea
> > 
> > On Sun, Feb 12, 2012 at 8:21 AM, Andrea Righi <andrea@...terlinux.com> wrote:
> > [...]
> > >  - Some of the routines to implement the generic interval tree has been taken
> > >   from the x86 PAT code, that uses interval trees to keep track of PAT ranges
> > >   (in the future it would be interesting to convert also the x86 PAT code to
> > >   use the generic interval tree implementation).
> > >
> > Perhaps the tree implemented in this work could also be used in tracking
> > regions in mm/hugetlb.c.
> > 
> > Thanks
> > Hillf
> 
> Thanks, Hillf.
> 
> Yes, I quickly looked at the hugtlb code, it seems another potential
> user of the interval tree. Now all the hugetlb regions are stored in a
> list, the interval tree is a more efficient structure for lookups -
> O(log(n)), so there are probably advantages in presence of many
> different disjoint intervals.
> 
> mmh... at the moment there's not a way to map region_count() with the
> current kinterval API, but we can easily extend it to provide also this
> feature (count the overlap size of two intervals).
> 

I am also extending the hugetlb region list in the hugetlb cgroup
patchset i recently posted to make sure we don't merge region if the
associated private data doesn't match (in my case it is the pointer to
hugetlb cgroup). Ref:
http://article.gmane.org/gmane.linux.kernel.mm/73829

The goal is to make sure a region add with different private value
results in below.


    old
      |       hcg1      |
      -------------------

new
|             hcg2               |
----------------------------------

results in 

 | hcg2   | |     hcg1       | |   hcg2 |
 ---------  __________________ ----------


-aneesh

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/