linux-kernel - Re: [PATCH -V2 0/9] memcg: add HugeTLB resource tracking

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]

Message-Id: <20120301144029.545a5589.akpm@linux-foundation.org>
Date:	Thu, 1 Mar 2012 14:40:29 -0800
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
Cc:	linux-mm@...ck.org, mgorman@...e.de,
	kamezawa.hiroyu@...fujitsu.com, dhillf@...il.com,
	aarcange@...hat.com, mhocko@...e.cz, hannes@...xchg.org,
	linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
	David Gibson <david@...son.dropbear.id.au>
Subject: Re: [PATCH -V2 0/9] memcg: add HugeTLB resource tracking

On Thu,  1 Mar 2012 14:46:11 +0530
"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com> wrote:

> This patchset implements a memory controller extension to control
> HugeTLB allocations. It is similar to the existing hugetlb quota
> support in that, the limit is enforced at mmap(2) time and not at
> fault time. HugeTLB's quota mechanism limits the number of huge pages
> that can allocated per superblock.
> 
> For shared mappings we track the regions mapped by a task along with the
> memcg. We keep the memory controller charged even after the task
> that did mmap(2) exits. Uncharge happens during truncate. For Private
> mappings we charge and uncharge from the current task cgroup.

I haven't begin to get my head around this yet, but I'd like to draw
your attention to https://lkml.org/lkml/2012/2/15/548.  That fix has
been hanging around for a while, but I haven't done anything with it
yet because I don't like its additional blurring of the separation
between hugetlb core code and hugetlbfs.  I want to find time to sit
down and see if the fix can be better architected but haven't got
around to that yet.

I expect that your patches will conflict at least mechanically with
David's, which is not a big issue.  But I wonder whether your patches
will copy the same bug into other places, and whether you can think of
a tidier way of addressing the bug which David is seeing?

--
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/