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Date:   Tue, 18 Dec 2018 12:20:37 +0100
From:   Peter Zijlstra <peterz@infradead.org>
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tejun Heo <tj@kernel.org>, lizefan@huawei.com,
        Johannes Weiner <hannes@cmpxchg.org>, axboe@kernel.dk,
        dennis@kernel.org, Dennis Zhou <dennisszhou@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jonathan Corbet <corbet@lwn.net>, cgroups@vger.kernel.org,
        linux-mm <linux-mm@kvack.org>, linux-doc@vger.kernel.org,
        LKML <linux-kernel@vger.kernel.org>, kernel-team@android.com
Subject: Re: [PATCH 6/6] psi: introduce psi monitor
Message-ID: <20181218112037.GB16284@hirez.programming.kicks-ass.net>
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On Tue, Dec 18, 2018 at 11:46:22AM +0100, Peter Zijlstra wrote:
> On Mon, Dec 17, 2018 at 05:21:05PM -0800, Suren Baghdasaryan wrote:
> > On Mon, Dec 17, 2018 at 8:22 AM Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > > How well has this thing been fuzzed? Custom string parser, yay!
> > 
> > Honestly, not much. Normal cases and some obvious corner cases. Will
> > check if I can use some fuzzer to get more coverage or will write a
> > script.
> > I'm not thrilled about writing a custom parser, so if there is a
> > better way to handle this please advise.
> 
> The grammar seems fairly simple, something like:
> 
>   some-full = "some" | "full" ;
>   threshold-abs = integer ;
>   threshold-pct = integer, { "%" } ;

Sorry, no {} there obviously. That '%' isn't optional.

>   threshold = threshold-abs | threshold-pct ;
>   window = integer ;
>   trigger = some-full, space, threshold, space, window ;

Clearly it's been a fair while since I wrote BNF like stuff ;-)