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: <b26fc2d6-207c-4d93-b9a3-1fa81fd89f6c@intel.com>
Date: Fri, 23 Feb 2024 13:19:01 -0800
From: Dave Hansen <dave.hansen@...el.com>
To: John Groves <John@...ves.net>, Dan Williams <dan.j.williams@...el.com>
Cc: John Groves <jgroves@...ron.com>, Jonathan Corbet <corbet@....net>,
 Vishal Verma <vishal.l.verma@...el.com>, Dave Jiang <dave.jiang@...el.com>,
 Alexander Viro <viro@...iv.linux.org.uk>,
 Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
 Matthew Wilcox <willy@...radead.org>, linux-cxl@...r.kernel.org,
 linux-fsdevel@...r.kernel.org, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org, nvdimm@...ts.linux.dev, john@...alactic.com,
 Dave Chinner <david@...morbit.com>, Christoph Hellwig <hch@...radead.org>,
 dave.hansen@...ux.intel.com, gregory.price@...verge.com
Subject: Re: [RFC PATCH 16/20] famfs: Add fault counters

On 2/23/24 12:39, John Groves wrote:
>> We had similar unit test regression concerns with fsdax where some
>> upstream change silently broke PMD faults. The solution there was trace
>> points in the fault handlers and a basic test that knows apriori that it
>> *should* be triggering a certain number of huge faults:
>>
>> https://github.com/pmem/ndctl/blob/main/test/dax.sh#L31
> Good approach, thanks Dan! My working assumption is that we'll be able to make
> that approach work in the famfs tests. So the fault counters should go away
> in the next version.

I do really suspect there's something more generic that should be done
here.  Maybe we need a generic 'huge_faults' perf event to pair up with
the good ol' faults that we already have:

# perf stat -e faults /bin/ls

 Performance counter stats for '/bin/ls':

               104      faults


       0.001499862 seconds time elapsed

       0.001490000 seconds user
       0.000000000 seconds sys




Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ