From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Jiri Kosina <jikos@kernel.org>, Miroslav Benes <mbenes@suse.cz>,
Petr Mladek <pmladek@suse.com>
Subject: Re: [PATCH 03/11 v3] ftrace: Optimize testing what context current is in
Date: Mon, 9 Nov 2020 11:51:51 -0500 [thread overview]
Message-ID: <20201109115151.1d841d97@oasis.local.home> (raw)
In-Reply-To: <20201109121708.GK2594@hirez.programming.kicks-ass.net>
On Mon, 9 Nov 2020 13:17:08 +0100
Peter Zijlstra <peterz@infradead.org> wrote:
> This patch is misleading, it doesn't optimize it nearly as much as is
> possible and actually fixes the softirq case, which isn't at all
> mentioned.
This is actually an old patch I had for some time (it's been in the
ring buffer code for a while). I honestly didn't even realize that it
fixed softirq, which is why it isn't mentioned ;-)
I only said "optimize" I didn't say "optimal", thus it can be improved
more. When I first wrote this, I saw non noise improvements with it, so
it does indeed optimize it.
>
> Let me go do that other patch.
I'll keep this patch, and replace the code when your version is
available.
Thanks!
-- Steve
next prev parent reply other threads:[~2020-11-09 16:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-06 2:32 [PATCH 00/11 v3] ftrace: Have callbacks handle their own recursion Steven Rostedt
2020-11-06 2:32 ` [PATCH 01/11 v3] ftrace: Move the recursion testing into global headers Steven Rostedt
2020-11-06 2:32 ` [PATCH 02/11 v3] ftrace: Add ftrace_test_recursion_trylock() helper function Steven Rostedt
2020-11-06 2:32 ` [PATCH 03/11 v3] ftrace: Optimize testing what context current is in Steven Rostedt
2020-11-09 12:17 ` Peter Zijlstra
2020-11-09 16:51 ` Steven Rostedt [this message]
2020-11-06 2:32 ` [PATCH 04/11 v3] pstore/ftrace: Add recursion protection to the ftrace callback Steven Rostedt
2020-11-06 2:32 ` [PATCH 05/11 v3] kprobes/ftrace: " Steven Rostedt
2020-11-06 10:25 ` Masami Hiramatsu
2020-11-06 2:32 ` [PATCH 06/11 v3] livepatch/ftrace: " Steven Rostedt
2020-11-06 10:05 ` Miroslav Benes
2020-11-06 2:32 ` [PATCH 07/11 v3] livepatch: Trigger WARNING if livepatch function fails due to recursion Steven Rostedt
2020-11-06 10:07 ` Miroslav Benes
2020-11-06 2:32 ` [PATCH 08/11 v3] perf/ftrace: Add recursion protection to the ftrace callback Steven Rostedt
2020-11-06 2:32 ` [PATCH 09/11 v3] perf/ftrace: Check for rcu_is_watching() in callback function Steven Rostedt
2020-11-06 2:32 ` [PATCH 10/11 v3] ftrace: Reverse what the RECURSION flag means in the ftrace_ops Steven Rostedt
2020-11-06 2:32 ` [PATCH 11/11 v3] ftrace: Add recording of functions that caused recursion Steven Rostedt
2020-11-06 13:13 ` Petr Mladek
2020-11-06 13:41 ` Steven Rostedt
2020-11-06 14:27 ` Petr Mladek
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