linux-kernel - Re: [PATCH v2 3/3] mm/slub: Use percpu partial free counter

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:   Wed, 3 Mar 2021 14:26:12 +0000
From:   Matthew Wilcox <willy@...radead.org>
To:     Christoph Lameter <cl@...two.de>
Cc:     Xunlei Pang <xlpang@...ux.alibaba.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Wen Yang <wenyang@...ux.alibaba.com>,
        Roman Gushchin <guro@...com>, Pekka Enberg <penberg@...il.com>,
        Konstantin Khlebnikov <khlebnikov@...dex-team.ru>,
        David Rientjes <rientjes@...gle.com>,
        linux-kernel@...r.kernel.org,
        "linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: Re: [PATCH v2 3/3] mm/slub: Use percpu partial free counter

On Tue, Mar 02, 2021 at 10:14:53AM +0100, Christoph Lameter wrote:
> On Mon, 10 Aug 2020, Xunlei Pang wrote:
> > -	atomic_long_t partial_free_objs;
> > +	atomic_long_t __percpu *partial_free_objs;
> 
> A percpu counter is never atomic. Just use unsigned long and use this_cpu
> operations for this thing. That should cut down further on the overhead.

What about allocations from interrupt context?  Should this be a local_t
instead?