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charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1c9b879a-7907-4849-a416-5df3db5617d6@kernel.org> On Wed, Feb 25, 2026 at 08:16:46AM +0100, Christophe Leroy (CS GROUP) wrote: > +Peter > > Hi Christian, > > Le 25/02/2026 à 06:54, Christian Zigotzky a écrit : > > Hello, > > > > We were previously able to disable PREEMPT in the kernel configuration, > > but the latest kernels now enable it by default and it is no longer > > possible to disable it. > > > > Is it possible to let us decide whether to activate PREEMPT or not? > > Can you give more details on why you want to be able to deactivate PREEMPT ? > > Read https://github.com/torvalds/linux/commit/7dadeaa6e851e Right. So to recap, there are and will be more cases where relying on preemption is mandatory. The typical example is huge page memset/memcpy. Currently that is done in single page chunks with cond_resched() in between, but it is much better (and faster) to do a full huge page in one go. Combine this with the endless stream of mostly random cond_resched() placements due to $reason, and it is all a bit of a maintenance nightmare. I suppose the question is; why do you think you require non-preempt kernels?