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 for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20191104152517.GD10485@infradead.org>
Date:   Mon, 4 Nov 2019 07:25:17 -0800
From:   Christoph Hellwig <hch@...radead.org>
To:     Shaokun Zhang <zhangshaokun@...ilicon.com>
Cc:     linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        Yang Guo <guoyang2@...wei.com>,
        "Darrick J. Wong" <darrick.wong@...cle.com>
Subject: Re: [PATCH] xfs: optimise xfs_mod_icount/ifree when delta < 0

On Mon, Nov 04, 2019 at 07:29:40PM +0800, Shaokun Zhang wrote:
> From: Yang Guo <guoyang2@...wei.com>
> 
> percpu_counter_compare will be called by xfs_mod_icount/ifree to check
> whether the counter less than 0 and it is a expensive function.
> let's check it only when delta < 0, it will be good for xfs's performance.

How much overhead do you see?  In the end the compare is just a debug
check, so if it actually shows up we should remove it entirely.

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ