Re: [PATCH] io_uring/napi: remove duplicate io_napi_entry timeout assignation

[Olivier Langlois <olivier@trillion01.com>]

On Tue, 2024-08-13 at 12:35 -0600, Jens Axboe wrote:
> On 8/13/24 11:22 AM, Olivier Langlois wrote:
> > On Mon, 2024-08-12 at 14:40 -0600, Jens Axboe wrote:
> > > 
> > > 
> > > > 3. I am surprised to notice that in __io_napi_do_busy_loop(),
> > > > list_for_each_entry_rcu() is called to traverse the list but
> > > > the
> > > > regular methods list_del() and list_add_tail() are called to
> > > > update
> > > > the
> > > > list instead of their RCU variant.
> > > 
> > > Should all just use rcu variants.
> > > 
> > > Here's a mashup of the changes. Would be great if you can test -
> > > I'll
> > > do
> > > some too, but always good with more than one person testing as it
> > > tends
> > > to hit more cases.
> > > 
> > Jens,
> > 
> > I have integrated our RCU corrections into
> > https://lore.kernel.org/io-uring/5fc9dd07e48a7178f547ed1b2aaa0814607fa246.1723567469.git.olivier@trillion01.com/T/#u
> > 
> > and my testing so far is not showing any problems...
> > but I have a very static setup...
> > I had no issues too without the corrections...
> 
> Thanks for testing, but regardless of whether that series would go in
> or
> not, I think those rcu changes should be done separately and upfront
> rather than be integrated with other changes.
> 
sorry about that...

I am going to share a little bit how I currently feel. I feel
disappointed because when I reread your initial reply, I have not been
able to spot a single positive thing said about my proposal despite
that I have prealably tested the water concerning my idea and the big
lines about how I was planning to design it. All, I have been told from
Pavel that the idea was so great that he was even currently playing
with a prototype around the same concept:
https://lore.kernel.org/io-uring/1be64672f22be44fbe1540053427d978c0224dfc.camel@trillion01.com/T/#mc7271764641f9c810ea5438ed3dc0662fbc08cb6

you also have to understand that all the small napi issues that I have
fixed this week are no stranger from me working on this new idea. The
RCU issues that I have reported back have been spotted when I was doing
my final code review before testing my patch before submitting it.

keep in mind that I am by far a git magician. I am a very casual
user... Anything that is outside the usual beaten trails such as
reordoring commits or breaking them down feels perilious to me...

I had 230+ lines changes committed when you confirmed that few lines
should be changed to address this new RCU issue. I did figure that it
would not that big a deal to include them with the rest of my change.

that being said, if my patch submission is acceptable conditional to
needed rework, I am willing to learn how to better use git to meet your
requirements.

Greetings,