Re: [PATCH RFC net-next v2 7/7] net: skbuff: always try to recycle PP pages directly when in softirq

From: Yunsheng Lin <redacted>
Date: Fri, 21 Jul 2023 19:53:33 +0800

On 2023/7/21 3:46, Jakub Kicinski wrote:

quoted

On Thu, 20 Jul 2023 21:33:40 +0200 Alexander Lobakin wrote:

quoted

quoted

We can as well check
	(in_softirq() && !irqs_disabled() && !in_hardirq())
?  

Yes, something like that. Messy, but I see no other options...

So, I guess you want to add an assertion to make sure that we're *not*
in this:

in_hardirq() || irqs_disabled()

Does this mean that after it's added, my patch is sane? :p

Well... it's acceptable. Make sure you add a good, informative
but concise comment :)

Does it mean ptr_ring_produce_any() is needed in
page_pool_recycle_in_ring() too?

As it is assumed that page pool API can be called in the context with
irqs_disabled() || in_hardirq(), and force recylcling happens in the
prt_ring.

Isn't it conflit with the below patch? as the below patch assume page
pool API can not be called in the context with irqs_disabled() || in_hardirq():
[PATCH net-next] page_pool: add a lockdep check for recycling in hardirq

Or am I missing something obvious here?

No, Page Pool is *not* intended to be called when IRQs are disabled,
hence the fix Jakub's posted in the separate thread.

Thanks,
Olek