From: Gang Li <ligang.bdlg@bytedance.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>,
Ingo Molnar <mingo@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
LKML <linux-kernel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>
Subject: Re: Re: [PATCH 3/3] mm: mmap_lock: add ip to mmap_lock tracepoints
Date: Mon, 2 Aug 2021 10:44:56 +0800 [thread overview]
Message-ID: <89c20b62-c0ab-3200-fb33-eb2058b7ba67@bytedance.com> (raw)
In-Reply-To: <20210730160319.6dfeaf7a@oasis.local.home>
On 7/31/21 4:03 AM, Steven Rostedt wrote:
> Yes, synthetic events are just like normal events, and have triggers,
> stack traces, and do pretty much anything that another event can do.
>
> I'm just finishing up a libtracfs called tracefs_sql() (hopefully
> posting it today), that allows you to create a synthetic event via an
> SQL statement. But I don't think this is what you are looking for.
>
> What about using function tracing? Because the tracepoint is called
> from __mmap_lock* helper functions that function tracer can see, you
> can just do the following:
>
> # trace-cmd start -e mmap_lock -p function -l '__mmap_lock_*'
> # trace-cmd show
> [..]
> trace-cmd-1840 [006] .... 194.576801: __mmap_lock_do_trace_start_locking <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576805: mmap_lock_start_locking: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false
>
> trace-cmd-1840 [006] .... 194.576806: __mmap_lock_do_trace_acquire_returned <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576807: mmap_lock_acquire_returned: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false success=true
>
> trace-cmd-1840 [006] .... 194.576811: __mmap_lock_do_trace_released <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576812: mmap_lock_released: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false
>
> trace-cmd-1840 [006] .... 194.576815: __mmap_lock_do_trace_start_locking <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576816: mmap_lock_start_locking: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false
>
> trace-cmd-1840 [006] .... 194.576816: __mmap_lock_do_trace_acquire_returned <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576817: mmap_lock_acquire_returned: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false success=true
>
> trace-cmd-1840 [006] .... 194.576820: __mmap_lock_do_trace_released <-do_user_addr_fault
> trace-cmd-1840 [006] ...1 194.576821: mmap_lock_released: mm=000000006515cb1f memcg_path=/user.slice/user-0.slice/session-2.scope write=false
>
>
> This looks exactly like the robots you are looking for.
>
> -- Steve
>
I think this is exactly what I am looking for.
Thanks!
next prev parent reply other threads:[~2021-08-02 2:45 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-29 9:28 [PATCH 3/3] mm: mmap_lock: add ip to mmap_lock tracepoints Gang Li
2021-07-29 17:33 ` Axel Rasmussen
2021-07-30 5:32 ` Gang Li
2021-07-30 20:03 ` Steven Rostedt
2021-08-02 2:44 ` Gang Li [this message]
2021-08-19 18:18 ` Gang Li
2021-08-31 3:24 ` Gang Li
2021-07-30 8:12 ` Vlastimil Babka
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