Re: [PATCH] Documentation/no_hz: Remove description that states boot CPU cannot be nohz_full

[Krishanth Jagaduri]

On Wed, Feb 05, 2025 at 10:18:17AM +0100, Greg KH wrote:
> On Wed, Feb 05, 2025 at 08:32:14AM +0530, Krishanth Jagaduri via B4 Relay wrote:
> > From: Oleg Nesterov <oleg@xxxxxxxxxx>
> > 
> > [ Upstream commit 5097cbcb38e6e0d2627c9dde1985e91d2c9f880e ]
> 
> It's just the documentation part of that commit, not the full one.
> 

Updated in v2. Thank you.

> > Documentation/timers/no_hz.rst states that the "nohz_full=" mask must not
> > include the boot CPU, which is no longer true after:
> > 
> >   commit 08ae95f4fd3b ("nohz_full: Allow the boot CPU to be nohz_full").
> > 
> > Apply changes only to Documentation/timers/no_hz.rst in stable kernels.
> 
> You dropped the rest of the changelog text here :(
>

Updated in v2. Thank you.

> > 
> > Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx # 5.4+
> > Signed-off-by: Krishanth Jagaduri <Krishanth.Jagaduri@xxxxxxxx>
> 
> And you dropped all the other signed-off-by lines :(
>

Updated in v2. Thank you.

> > While it fixes the document description, it also fixes issue introduced
> > by another commit aae17ebb53cd ("workqueue: Avoid using isolated cpus'
> > timers on queue_delayed_work").
> > 
> > It is unlikely that it will be backported to stable kernels which does
> > not contain the commit that introduced the issue.
> > 
> > Could Documentation/timers/no_hz.rst be fixed in stable kernels 5.4+?
> 
> Does the documentation lines really matter here?
> 

When we tried LTS kernels 5.4 to 6.6, we noticed that boot CPU can be
nohz_full without any problems. But information in documentation was
misleading. We wanted to check if it would be okay to fix the information
in the document.

> At the very least, we can't take this as the signed-off-by lines are all
> gone.  Please resend with them all back, and then make a note that you
> are only including the documentation portion and why.
>
Updated in v2. Thank you.

Best regards,
Krishanth