From: Steven Rostedt <rostedt@goodmis.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vincent Donnefort <vdonnefort@google.com>,
Joel Fernandes <joel@joelfernandes.org>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
suleiman@google.com, Thomas Gleixner <tglx@linutronix.de>,
Vineeth Pillai <vineeth@bitbyteword.org>,
Youssef Esmat <youssefesmat@google.com>,
Beau Belgrave <beaub@linux.microsoft.com>,
Alexander Graf <graf@amazon.com>, Baoquan He <bhe@redhat.com>,
Borislav Petkov <bp@alien8.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
David Howells <dhowells@redhat.com>,
Mike Rapoport <rppt@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Ross Zwisler <zwisler@google.com>,
Kees Cook <keescook@chromium.org>
Subject: Re: [PATCH v4 01/13] ring-buffer: Allow mapped field to be set without mapping
Date: Tue, 11 Jun 2024 21:57:18 -0400 [thread overview]
Message-ID: <20240611215718.03eb9fc0@rorschach.local.home> (raw)
In-Reply-To: <20240611213937.408770fa@rorschach.local.home>
On Tue, 11 Jun 2024 21:39:37 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Maybe explain why sometimes __rb_inc_dec_mapped() is called to
> > increment or decrement ->mapped, and sometimes it id done directly ?
> > I can see that the function also acquires the buffer mutex, which
> > isn't needed at the places where mapped is incremented/decremented
> > directly, but common code would still be nice, and it is odd to see
> > over/underflows handled sometimes but not always.
>
> Sure. I'll add comments explaining more.
And I found a bug with this code. It assumes that mapped will be equal
to 1 if it's the last mapping. That will no longer be the case.
-- Steve
next prev parent reply other threads:[~2024-06-12 1:57 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-11 19:28 [PATCH v4 00/13] tracing: Persistent traces across a reboot or crash Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 01/13] ring-buffer: Allow mapped field to be set without mapping Steven Rostedt
2024-06-11 22:43 ` Guenter Roeck
2024-06-11 22:53 ` Steven Rostedt
2024-06-11 23:53 ` Guenter Roeck
2024-06-12 1:39 ` Steven Rostedt
2024-06-12 1:57 ` Steven Rostedt [this message]
2024-06-11 19:28 ` [PATCH v4 02/13] ring-buffer: Add ring_buffer_alloc_range() Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 03/13] ring-buffer: Add ring_buffer_meta data Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 04/13] tracing: Implement creating an instance based on a given memory region Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 05/13] ring-buffer: Add output of ring buffer meta page Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 06/13] ring-buffer: Add test if range of boot buffer is valid Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 07/13] ring-buffer: Validate boot range memory events Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 08/13] tracing: Add option to use memmapped memory for trace boot instance Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 09/13] ring-buffer: Save text and data locations in mapped meta data Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 10/13] tracing/ring-buffer: Add last_boot_info file to boot instance Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 11/13] tracing: Handle old buffer mappings for event strings and functions Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 12/13] tracing: Update function tracing output for previous boot buffer Steven Rostedt
2024-06-11 19:28 ` [PATCH v4 13/13] tracing: Add last boot delta offset for stack traces Steven Rostedt
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