linux-kernel - Re: [PATCH v2 1/4] tracing/histogram: Optimize division by constants

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:   Fri, 29 Oct 2021 16:25:49 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     Kalesh Singh <kaleshsingh@...gle.com>
Cc:     surenb@...gle.com, hridya@...gle.com, namhyung@...nel.org,
        kernel-team@...roid.com, mhiramat@...nel.org,
        Jonathan Corbet <corbet@....net>,
        Ingo Molnar <mingo@...hat.com>, Shuah Khan <shuah@...nel.org>,
        Tom Zanussi <zanussi@...nel.org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH v2 1/4] tracing/histogram: Optimize division by
 constants

On Fri, 29 Oct 2021 11:53:16 -0700
Kalesh Singh <kaleshsingh@...gle.com> wrote:

> > If these functions are only called when val2 is constant, can't we make it
> > such that we get val2 from the hist_field directly? That is:
> >
> >         u64 val2 = operand2->constant;  
> 
> operand2 might be a var ref to a constant, so we would need to resolve
> that with hist_field_var_ref().

So can a var_ref change? If not, then we should convert that to a constant
for this operation.

-- Steve