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Date: Mon, 3 Jun 2024 13:05:04 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Mark
 Rutland <mark.rutland@arm.com>, Mathieu Desnoyers
 <mathieu.desnoyers@efficios.com>, Andrew Morton
 <akpm@linux-foundation.org>, Alexei Starovoitov
 <alexei.starovoitov@gmail.com>, Florent Revest <revest@chromium.org>,
 Martin KaFai Lau <martin.lau@linux.dev>, bpf <bpf@vger.kernel.org>, Sven
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 Peter Zijlstra <peterz@infradead.org>, Thomas Gleixner
 <tglx@linutronix.de>, Guo Ren <guoren@kernel.org>
Subject: Re: [PATCH v2 10/27] ftrace: Add subops logic to allow one ops to
 manage many
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On Mon, 3 Jun 2024 11:46:36 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:

> > > at the beginning of the loop.
> > > Also, at the end of the loop,
> > > 
> > > if (ftrace_hash_empty(new_hash)) {
> > > 	free_ftrace_hash(new_hash);
> > > 	new_hash = EMPTY_HASH;
> > > 	break;
> > > }  
> 
> And we still need this (I think this should be done in intersect_hash(), we just
> need to count the number of entries.) 

Ah, I see. if it ends with nothing intersecting it should be empty. I added:

	/* If nothing intersects, make it the empty set */
	if (ftrace_hash_empty(*hash)) {
		free_ftrace_hash(*hash);
		*hash = EMPTY_HASH;
	}

to the end of intersect_hash().

-- Steve