From: Byungchul Park <byungchul.park@lge.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com>,
linux-ide@vger.kernel.org,
Andreas Dilger <adilger.kernel@dilger.ca>,
Ext4 Developers List <linux-ext4@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Will Deacon <will@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
Joel Fernandes <joel@joelfernandes.org>,
Sasha Levin <sashal@kernel.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Chris Wilson <chris@chris-wilson.co.uk>,
duyuyang@gmail.com, johannes.berg@intel.com,
Tejun Heo <tj@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
Matthew Wilcox <willy@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Amir Goldstein <amir73il@gmail.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
kernel-team@lge.com, Linux-MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Minchan Kim <minchan@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
sj@kernel.org, Jerome Glisse <jglisse@redhat.com>,
Dennis Zhou <dennis@kernel.org>, Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
ngupta@vflare.org, linux-block <linux-block@vger.kernel.org>,
paolo.valente@linaro.org, Josef Bacik <josef@toxicpanda.com>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>, Jan Kara <jack@suse.cz>,
jack@suse.com, Jeff Layton <jlayton@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J. Wong" <djwong@kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Dave Airlie <airlied@linux.ie>,
rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com,
hamohammed.sa@gmail.com, 42.hyeyoo@gmail.com
Subject: Re: [PATCH RFC v6 00/21] DEPT(Dependency Tracker)
Date: Mon, 9 May 2022 10:22:02 +0900 [thread overview]
Message-ID: <20220509012202.GB6047@X58A-UD3R> (raw)
In-Reply-To: <CAHk-=whnPePcffsNQM+YSHMGttLXvpf8LbBQ8P7HEdqFXaV7Lg@mail.gmail.com>
On Wed, May 04, 2022 at 11:17:02AM -0700, Linus Torvalds wrote:
> On Wed, May 4, 2022 at 1:19 AM Byungchul Park <byungchul.park@lge.com> wrote:
> >
> > Hi Linus and folks,
> >
> > I've been developing a tool for detecting deadlock possibilities by
> > tracking wait/event rather than lock(?) acquisition order to try to
> > cover all synchonization machanisms.
>
> So what is the actual status of reports these days?
I'd like to mention one important thing here. Reportability would get
stronger if the more wait-event pairs get tagged everywhere DEPT can
work.
Everything e.g. HW-SW interface, any retry logic and so on can be a
wait-event pair if they work wait or event anyway. For example, polling
on an IO mapped read register and initiating the HW to go for the event
also can be a pair. Definitely those make DEPT more useful.
---
The way to use the APIs:
1. Define SDT(Simple Dependency Tracker)
DEFINE_DEPT_SDT(my_hw_event); <- add this
2. Tag on the waits
sdt_wait(&my_hw_event); <- add this
... retry logic until my hw work done ... <- the original code
3. Tag on the events
sdt_event(&my_hw_event); <- add this
run_my_hw(); <- the original code
---
These are all we should do. I believe DEPT would be a very useful tool
once all wait-event pairs get tagged by the developers in all subsystems
and device drivers.
Byungchul
> Last time I looked at some reports, it gave a lot of false positives
> due to mis-understanding prepare_to_sleep().
>
> For this all to make sense, it would need to not have false positives
> (or at least a very small number of them together with a way to sanely
> get rid of them), and also have a track record of finding things that
> lockdep doesn't.
>
> Maybe such reports have been sent out with the current situation, and
> I haven't seen them.
>
> Linus
next prev parent reply other threads:[~2022-05-09 1:30 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-04 8:17 [PATCH RFC v6 00/21] DEPT(Dependency Tracker) Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 01/21] llist: Move llist_{head,node} definition to types.h Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 02/21] dept: Implement Dept(Dependency Tracker) Byungchul Park
2022-05-21 3:24 ` Hyeonggon Yoo
2022-05-04 8:17 ` [PATCH RFC v6 03/21] dept: Apply Dept to spinlock Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 04/21] dept: Apply Dept to mutex families Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 05/21] dept: Apply Dept to rwlock Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 06/21] dept: Apply Dept to wait_for_completion()/complete() Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 07/21] dept: Apply Dept to seqlock Byungchul Park
2022-05-21 5:25 ` Hyeonggon Yoo
2022-05-24 6:00 ` Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 08/21] dept: Apply Dept to rwsem Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 09/21] dept: Add proc knobs to show stats and dependency graph Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 10/21] dept: Introduce split map concept and new APIs for them Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 11/21] dept: Apply Dept to wait/event of PG_{locked,writeback} Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 12/21] dept: Apply SDT to swait Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 13/21] dept: Apply SDT to wait(waitqueue) Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 14/21] locking/lockdep, cpu/hotplus: Use a weaker annotation in AP thread Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 15/21] dept: Distinguish each syscall context from another Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 16/21] dept: Distinguish each work " Byungchul Park
2022-05-04 11:23 ` Sergey Shtylyov
2022-05-04 8:17 ` [PATCH RFC v6 17/21] dept: Disable Dept within the wait_bit layer by default Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 18/21] dept: Disable Dept on struct crypto_larval's completion for now Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 19/21] dept: Differentiate onstack maps from others of different tasks in class Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 20/21] dept: Do not add dependencies between events within scheduler and sleeps Byungchul Park
2022-05-04 8:17 ` [PATCH RFC v6 21/21] dept: Unstage wait when tagging a normal sleep wait Byungchul Park
2022-05-04 18:17 ` [PATCH RFC v6 00/21] DEPT(Dependency Tracker) Linus Torvalds
2022-05-06 0:11 ` Byungchul Park
2022-05-07 7:20 ` Hyeonggon Yoo
2022-05-09 0:16 ` Byungchul Park
2022-05-09 20:47 ` Steven Rostedt
2022-05-09 23:38 ` Byungchul Park
2022-05-10 14:12 ` Steven Rostedt
2022-05-10 23:26 ` Byungchul Park
2022-05-10 11:18 ` Hyeonggon Yoo
2022-05-10 23:39 ` Byungchul Park
2022-05-11 10:04 ` Hyeonggon Yoo
2022-05-19 10:11 ` Catalin Marinas
2022-05-23 2:43 ` Byungchul Park
2022-05-09 1:22 ` Byungchul Park [this message]
2022-05-09 21:05 ` Theodore Ts'o
2022-05-09 22:28 ` Theodore Ts'o
2022-05-10 0:32 ` Byungchul Park
2022-05-10 1:32 ` Theodore Ts'o
2022-05-10 5:37 ` Byungchul Park
2022-05-11 1:16 ` Byungchul Park
2022-05-12 5:25 ` [REPORT] syscall reboot + umh + firmware fallback Byungchul Park
2022-05-12 9:15 ` Tejun Heo
2022-05-12 11:18 ` Byungchul Park
2022-05-12 13:56 ` Theodore Ts'o
2022-05-23 1:10 ` Byungchul Park
2022-05-12 16:41 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220509012202.GB6047@X58A-UD3R \
--to=byungchul.park@lge.com \
--cc=42.hyeyoo@gmail.com \
--cc=adilger.kernel@dilger.ca \
--cc=airlied@linux.ie \
--cc=akpm@linux-foundation.org \
--cc=amir73il@gmail.com \
--cc=bfields@fieldses.org \
--cc=chris@chris-wilson.co.uk \
--cc=cl@linux.com \
--cc=damien.lemoal@opensource.wdc.com \
--cc=dan.j.williams@intel.com \
--cc=daniel.vetter@ffwll.ch \
--cc=david@fromorbit.com \
--cc=dennis@kernel.org \
--cc=djwong@kernel.org \
--cc=dri-devel@lists.freedesktop.org \
--cc=duyuyang@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=hamohammed.sa@gmail.com \
--cc=hannes@cmpxchg.org \
--cc=hch@infradead.org \
--cc=jack@suse.com \
--cc=jack@suse.cz \
--cc=jglisse@redhat.com \
--cc=jlayton@kernel.org \
--cc=joel@joelfernandes.org \
--cc=johannes.berg@intel.com \
--cc=josef@toxicpanda.com \
--cc=kernel-team@lge.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-ext4@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-ide@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=melissa.srw@gmail.com \
--cc=mhocko@kernel.org \
--cc=minchan@kernel.org \
--cc=mingo@redhat.com \
--cc=ngupta@vflare.org \
--cc=paolo.valente@linaro.org \
--cc=penberg@kernel.org \
--cc=peterz@infradead.org \
--cc=rientjes@google.com \
--cc=rodrigosiqueiramelo@gmail.com \
--cc=rostedt@goodmis.org \
--cc=sashal@kernel.org \
--cc=sj@kernel.org \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=tytso@mit.edu \
--cc=vbabka@suse.cz \
--cc=vdavydov.dev@gmail.com \
--cc=viro@zeniv.linux.org.uk \
--cc=will@kernel.org \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).