Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Thomas Gleixner <tglx@linutronix.de>
To:     Prakash Sangappa <prakash.sangappa@oracle.com>
Cc:     Davidlohr Bueso <dave@stgolabs.net>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "manfred@colorfullife.com" <manfred@colorfullife.com>
Subject: Re: [PATCH v3] ipc: Update semtimedop() to use hrtimer
In-Reply-To: <5FEE7AB6-7560-4998-A7A3-B60A4B32E1DE@oracle.com>
References: <1651178767-447-1-git-send-email-prakash.sangappa@oracle.com>
 <20220428205001.hiuzwpn5emxtrh4s@offworld> <87zgk4ooi6.ffs@tglx>
 <5FEE7AB6-7560-4998-A7A3-B60A4B32E1DE@oracle.com>
Date:   Fri, 29 Apr 2022 00:41:03 +0200
Message-ID: <87tuacomps.ffs@tglx>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

On Thu, Apr 28 2022 at 22:23, Prakash Sangappa wrote:
>> On Apr 28, 2022, at 3:02 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
>> On Thu, Apr 28 2022 at 13:50, Davidlohr Bueso wrote:
>>> On Thu, 28 Apr 2022, Prakash Sangappa wrote:
>>>> -		if (timeout)
>>>> -			jiffies_left = schedule_timeout(jiffies_left);
>>>> -		else
>>>> -			schedule();
>>>> +		timed_out = !schedule_hrtimeout_range(exp,
>>>> +				current->timer_slack_ns, HRTIMER_MODE_ABS);
>>> 
>>> I'm wondering if the slack parameter instead of passing the timer_slack_ns
>>> value immediately, we should do a rt_task() check and pass zero if so.
>> 
>> We should have a wrapper function which takes care of that instead of
>> having checks all over the place.
>
> Ok  it can be an inline function in sched.h which returns appropriate 
> slack time. Use that in  futex_wait() and sigtimedwait() also in addition to 
> semtimedop() & mqueue codepath?

No. What I meant is a function which handles this internally, not an inline
function which has to be invoked on various call sites.

> Should that be a separate patch?

Definitely. That's an orthogonal problem.

Thanks,

        tglx