linux-kernel - Re: [PATCH] mm: move more expensive part of XA setup out of mapping check

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: <YXhEAZMf9Qrsev82@casper.infradead.org>
Date:   Tue, 26 Oct 2021 19:08:01 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     Jens Axboe <axboe@...nel.dk>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Linux Memory Management List <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm: move more expensive part of XA setup out of mapping
 check

On Tue, Oct 26, 2021 at 10:01:20AM -0600, Jens Axboe wrote:
> The fast path here is not needing any writeback, yet we spend time setting
> up the xarray lookup data upfront. Move the part that actually needs to
> iterate the address space mapping into a separate helper, saving ~30% of
> the time here.

No objection to this patch, but it did remind me that I never saw an answer to
https://lore.kernel.org/all/CAHk-=wg_-EwefQ_3Osz4iJxTrTk3tfrV53Z7-jaGg=tm9i5TXg@mail.gmail.com/
(and nor did lore)