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From: Ankur Arora <ankur.a.arora@oracle.com>
To: tglx@linutronix.de
Cc: ankur.a.arora@oracle.com, david@fromorbit.com, dchinner@redhat.com,
        djwong@kernel.org, hch@lst.de, linux-kernel@vger.kernel.org,
        linux-xfs@vger.kernel.org, wenjian1@xiaomi.com, wenjianhn@gmail.com
Subject: Re: [PATCH] xfs: explicitly call cond_resched in xfs_itruncate_extents_flags
Date: Mon, 22 Jan 2024 23:01:58 -0800
Message-Id: <20240123070158.4023269-1-ankur.a.arora@oracle.com>
In-Reply-To: <87v87yiu2g.ffs@tglx>
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[ Missed this email until now. ]

Thomas Gleixner writes:

>On Fri, Jan 12 2024 at 07:27, Dave Chinner wrote:
>
>Cc: Ankur
>
> > On Thu, Jan 11, 2024 at 08:52:22PM +0800, Jian Wen wrote:
> >> On Thu, Jan 11, 2024 at 5:38 AM Dave Chinner <david@fromorbit.com> wrote:
> >> > IOWs, this is no longer considered an acceptible solution by core
> >> > kernel maintainers.
> >> Understood. I will only build a hotfix for our production kernel then.
> >
> > Yeah, that may be your best short term fix. We'll need to clarify
> > what the current policy is on adding cond_resched points before we
> > go any further in this direction.
>
> Well, right now until the scheduler situation is sorted there is no
> other solution than to add the cond_resched() muck.
>
> > Thomas, any update on what is happening with cond_resched() - is
> > there an ETA on it going away/being unnecessary?
>
> Ankur is working on that...

Yeah, running through a final round of tests before sending out the series.

Dave, on the status of cond_resched(): the work on this adds a new scheduling
model (as Thomas implemented in his PoC) undwer which cond_resched() would
basically be a stub.

However, given that other preemption models continue to use cond_resched(),
we would need to live with cond_resched() for a while -- at least while
this model works well enough under a wide enough variety of loads.

Thanks
Ankur