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Subject: Re: [PATCH v3 20/21] dyndbg: add user-flag, negating-flags, and
 filtering on flags
From:   Joe Perches <joe@perches.com>
To:     Jim Cromie <jim.cromie@gmail.com>, jbaron@akamai.com,
        linux-kernel@vger.kernel.org, akpm@linuxfoundation.org,
        gregkh@linuxfoundation.org
Cc:     linux@rasmusvillemoes.dk, Jonathan Corbet <corbet@lwn.net>,
        Andrew Morton <akpm@linux-foundation.org>,
        Will Deacon <will@kernel.org>,
        Orson Zhai <orson.zhai@unisoc.com>,
        Petr Mladek <pmladek@suse.com>, linux-doc@vger.kernel.org
Date:   Wed, 17 Jun 2020 15:13:28 -0700
In-Reply-To: <20200617162536.611386-23-jim.cromie@gmail.com>
References: <20200617162536.611386-1-jim.cromie@gmail.com>
         <20200617162536.611386-23-jim.cromie@gmail.com>
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On Wed, 2020-06-17 at 10:25 -0600, Jim Cromie wrote:
> 1. Add a user-flag [u] which works like the [pfmlt] flags, but has no
> effect on callsite behavior; it allows incremental marking of
> arbitrary sets of callsites.
> 
> 2. Add [PFMLTU] flags, which negate their counterparts; P===!p etc.
> And in ddebug_read_flags():
>    current code does:	[pfmltu_] -> flags
>    copy it to:		[PFMLTU_] -> mask
> 
> also disallow both of a pair: ie no 'pP', no true & false.
> 
> 3. Add filtering ops into ddebug_change(), right after all the
> callsite-property selections are complete.  These filter on the
> callsite's current flagstate before applying modflags.
> 
> Why ?
> 
> The u-flag & filter flags
> 
> The 'u' flag lets the user assemble an arbitary set of callsites.
> Then using filter flags, user can activate the 'u' callsite set.
> 
>   #> echo 'file foo.c +u; file bar.c +u' > control   # and repeat
>   #> echo 'u+p' > control
> 
> Of course, you can continue to just activate your set without ever
> marking it 1st, but you could trivially add the markup as you go, then
> be able to use it as a constraint later, to undo or modify your set.

Does this set selection also allow for selection by
increasing decimal level?

Can sites be enabled for a value less than x?