linux-kernel - Re: [PATCH v5 04/18] rcu: Fix late wakeup when flush of bypass cblist happens

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Message-ID: <a99c817f-4b0f-ad50-db38-8a55029d6ecc@joelfernandes.org>
Date:   Tue, 6 Sep 2022 22:43:22 -0400
From:   Joel Fernandes <joel@...lfernandes.org>
To:     Frederic Weisbecker <frederic@...nel.org>
Cc:     rcu@...r.kernel.org, linux-kernel@...r.kernel.org,
        rushikesh.s.kadam@...el.com, urezki@...il.com,
        neeraj.iitr10@...il.com, paulmck@...nel.org, rostedt@...dmis.org,
        vineeth@...byteword.org, boqun.feng@...il.com
Subject: Re: [PATCH v5 04/18] rcu: Fix late wakeup when flush of bypass cblist
 happens



On 9/6/2022 5:48 AM, Frederic Weisbecker wrote:
>>  		}
>> -		rcu_nocb_unlock_irqrestore(rdp, flags);
>> +
>> +		// The flush succeeded and we moved CBs into the ->cblist.
>> +		// However, the bypass timer might still be running. Wakeup the
> That part of the comment mentioning the bypass timer looks strange...
> 
> 
>> +		// GP thread by calling a helper with was_all_done set so that
>> +		// wake up happens (needed if main CB list was empty before).
> How about:
> 
>                 // The flush succeeded and we moved CBs into the regular list.
> 		// Don't wait for the wake up timer as it may be too far ahead.
> 		// Wake up now GP thread instead if the cblist was empty
> 
> Thanks.
> 
> Other than that the patch looks good, thanks!
> 

I updated it accordingly and will send it for next revision, thank you!

 - Joel