From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07CC81534EC; Mon, 29 Jul 2024 14:49:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722264569; cv=none; b=C/uk+6skNvHXcfJ/PUhcUaliiZM50I4QOTNeXG0j5alie3DyQnZM3ZN5vJ1T5SaNV3RxB/F6rIsEfqwqwxOVxnJNH2SXmB+sX1PHoIoTlegoAMlD3KUQY536zxh6U9/W87QceGYTp1XZyBi3rfqIBRTFt33lwbs7JXrLjYoaPRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722264569; c=relaxed/simple; bh=o9d+uKlTPe2mDv83pCJEl1+vFwvuCqNcuo1JM8/jn60=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=r0tbbCxlHugv9UXs+//2zo8llLE+toEx+6kdbSZktS0LJSFfTLp58OBot0UlXpsl2v5ZAoQyEkpC7AEVcmbXu9UDJfR/ydfTowQ8fQZTdwjvnkCoHHc60SyD/awQqEBP/RIiHtJMwuwz+5mAahmDqYlDcy9WrbYHTk+UuUMmqm8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hajshv5z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hajshv5z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06D21C32786; Mon, 29 Jul 2024 14:49:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722264568; bh=o9d+uKlTPe2mDv83pCJEl1+vFwvuCqNcuo1JM8/jn60=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hajshv5zY4N7pSkiuJIXOSJTFrEIgJSnCCwtiDYTK2fgY5FWXbqu1svgCDZs63+rB YoRXpN7tXqsWNKuChT5X1jWd4KnBtScjh797QoNDbk5+LimfLmpOpRf6OczOzSO4IN aNsrjQxs8huVA4lWOqKvqIpWkFB8vpfRavsmiKz9dvgqY88Nop1j4C2lDuNgo0ZpJM OhsLQz0stPAXTF+jB/zq/YEYCWKK8Pe/QJJOB/LfWdhEm+Pc0ehKYz6OsBPIRgVoy3 xP+NEyOXzCHeE3bZvha9O8vREDpPijLjefnpApSa+g/YCJwl/Mpj72dronKCQDuoyg 26IYn5bXgLg0Q== Date: Mon, 29 Jul 2024 23:49:24 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: LKML , Linux trace kernel , Masami Hiramatsu , Mathieu Desnoyers Subject: Re: [PATCH] tracing: Use refcount for trace_event_file reference counter Message-Id: <20240729234924.6accc2e6216e3b7be1a97e61@kernel.org> In-Reply-To: <20240726144208.687cce24@rorschach.local.home> References: <20240726144208.687cce24@rorschach.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 26 Jul 2024 14:42:08 -0400 Steven Rostedt wrote: > From: Steven Rostedt > > Instead of using an atomic counter for the trace_event_file reference > counter, use the refcount interface. It has various checks to make sure > the reference counting is correct, and will warn if it detects an error > (like refcount_inc() on '0'). > > Signed-off-by: Steven Rostedt (Google) Looks good to me. Masami Hiramatsu (Google) Thanks, > --- > include/linux/trace_events.h | 2 +- > kernel/trace/trace_events.c | 8 ++++---- > 2 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h > index 9df3e2973626..fed58e54f15e 100644 > --- a/include/linux/trace_events.h > +++ b/include/linux/trace_events.h > @@ -680,7 +680,7 @@ struct trace_event_file { > * caching and such. Which is mostly OK ;-) > */ > unsigned long flags; > - atomic_t ref; /* ref count for opened files */ > + refcount_t ref; /* ref count for opened files */ > atomic_t sm_ref; /* soft-mode reference counter */ > atomic_t tm_ref; /* trigger-mode reference counter */ > }; > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 852643d957de..81ade9ddcbe5 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -992,18 +992,18 @@ static void remove_subsystem(struct trace_subsystem_dir *dir) > > void event_file_get(struct trace_event_file *file) > { > - atomic_inc(&file->ref); > + refcount_inc(&file->ref); > } > > void event_file_put(struct trace_event_file *file) > { > - if (WARN_ON_ONCE(!atomic_read(&file->ref))) { > + if (WARN_ON_ONCE(!refcount_read(&file->ref))) { > if (file->flags & EVENT_FILE_FL_FREED) > kmem_cache_free(file_cachep, file); > return; > } > > - if (atomic_dec_and_test(&file->ref)) { > + if (refcount_dec_and_test(&file->ref)) { > /* Count should only go to zero when it is freed */ > if (WARN_ON_ONCE(!(file->flags & EVENT_FILE_FL_FREED))) > return; > @@ -2999,7 +2999,7 @@ trace_create_new_event(struct trace_event_call *call, > atomic_set(&file->tm_ref, 0); > INIT_LIST_HEAD(&file->triggers); > list_add(&file->list, &tr->events); > - event_file_get(file); > + refcount_set(&file->ref, 1); > > return file; > } > -- > 2.43.0 > -- Masami Hiramatsu (Google)