linux-kernel - Re: [PATCH -V3] NUMA balancing: reduce TLB flush via delaying mapping on hint page fault

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] [day] [month] [year] [list]

Message-ID: <20210421074047.GD15768@suse.de>
Date:   Wed, 21 Apr 2021 08:40:47 +0100
From:   Mel Gorman <mgorman@...e.de>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Peter Zijlstra <peterz@...radead.org>,
        Peter Xu <peterx@...hat.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Matthew Wilcox <willy@...radead.org>,
        Will Deacon <will@...nel.org>,
        Michel Lespinasse <walken@...gle.com>,
        Arjun Roy <arjunroy@...gle.com>,
        Huang Ying <ying.huang@...el.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH -V3] NUMA balancing: reduce TLB flush via delaying
 mapping on hint page fault

On Thu, Apr 08, 2021 at 09:22:36PM +0800, Huang Ying wrote:
> With NUMA balancing, in hint page fault handler, the faulting page
> will be migrated to the accessing node if necessary.  During the
> migration, TLB will be shot down on all CPUs that the process has run
> on recently.  Because in the hint page fault handler, the PTE will be
> made accessible before the migration is tried.  The overhead of TLB
> shooting down can be high, so it's better to be avoided if possible.
> In fact, if we delay mapping the page until migration, that can be
> avoided.  This is what this patch doing.
> 

<SNIP>

> Signed-off-by: "Huang, Ying" <ying.huang@...el.com>
> Reviewed-by: Mel Gorman <mgorman@...e.de>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Peter Xu <peterx@...hat.com>
> Cc: Johannes Weiner <hannes@...xchg.org>
> Cc: Vlastimil Babka <vbabka@...e.cz>
> Cc: "Matthew Wilcox" <willy@...radead.org>
> Cc: Will Deacon <will@...nel.org>
> Cc: Michel Lespinasse <walken@...gle.com>
> Cc: Arjun Roy <arjunroy@...gle.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>

Hi Andrew,

I do not see this in the mmots tree. Was something missed in this patch
that needs fixing or did it just fall through the cracks?

Thanks.

-- 
Mel Gorman
SUSE Labs