From: Andrew Morton <akpm@linux-foundation.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Balbir Singh <balbirs@nvidia.com>,
linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org,
linux-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
David Hildenbrand <david@redhat.com>, Zi Yan <ziy@nvidia.com>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>, Byungchul Park <byungchul@sk.com>,
Gregory Price <gourry@gourry.net>,
Ying Huang <ying.huang@linux.alibaba.com>,
Alistair Popple <apopple@nvidia.com>
Subject: Re: [PATCH] mm/migrate_device: Add tracepoints for debugging
Date: Tue, 11 Nov 2025 15:50:42 -0800 [thread overview]
Message-ID: <20251111155042.b07ecb045c978fe4c457b1d0@linux-foundation.org> (raw)
In-Reply-To: <20251110161954.47d88433@gandalf.local.home>
On Mon, 10 Nov 2025 16:19:54 -0500 Steven Rostedt <rostedt@goodmis.org> wrote:
> On Thu, 16 Oct 2025 16:46:19 +1100
> Balbir Singh <balbirs@nvidia.com> wrote:
>
> > Add tracepoints for debugging device migration flow in migrate_device.c.
> > This is helpful in debugging how long migration took (time can be
> > tracked backwards from migrate_device_finalize to migrate_vma_setup).
> >
> > A combination of these events along with existing thp:*, exceptions:*
> > and migrate:* is very useful for debugging issues related to
> > migration.
> >
>
> ...
>
> > hmm-tests-855 [002] 50.042800: set_migration_pmd: addr=7f2908a00000, pmd=dfffffffd39ffe00
> > hmm-tests-855 [002] 50.062345: remove_migration_pmd: addr=7f2908a00000, pmd=efffffe00403fe00
>
> Each TRACE_EVENT() is equivalent to:
>
> DECLARE_EVENT_CLASS(event, ...)
> DEFINE_EVENT(event, event, ...)
>
> Where a class is around 4-5K in size, and the DEFINE_EVENT is between
> 500 and 1k in size.
>
> By using a single DECLARE_EVENT_CLASS() for multiple events, you can save
> several thousands of bytes of memory.
Thanks for the detailed review. I'll drop this version of the patch.
next prev parent reply other threads:[~2025-11-11 23:50 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-16 5:46 Balbir Singh
2025-11-10 21:19 ` Steven Rostedt
2025-11-11 23:50 ` Andrew Morton [this message]
2025-11-11 23:55 ` Balbir Singh
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