Re: [PATCH 00/10] Fix confusion around MAX_ORDER

From: Pavel Machek
Date: Tue Oct 17 2023 - 06:46:42 EST


On Thu 2023-09-28 18:57:18, Paolo Bonzini wrote:
> On 9/28/23 09:50, Mikulas Patocka wrote:
> > > > Fix the bugs and then change the definition of MAX_ORDER to be
> > > > inclusive: the range of orders user can ask from buddy allocator is
> > > > 0..MAX_ORDER now.
> > I think that exclusive MAX_ORDER is more intuitive in the C language -
> > i.e. if you write "for (i = 0; i < MAX_ORDER; i++)", you are supposed to
> > loop over all allowed values. If you declare an array "void
> > *array[MAX_ORDER];" you are supposed to hold a value for each allowed
> > order.
> >
> > Pascal has for loops and array dimensions with inclusive ranges - and it
> > is more prone to off-by-one errors.
>
> I agree it's somewhat confusing either way but the ship has sailed, the
> patch has been included in Linux for several months.

Just make sure people don't backport it to stable. Fixes: (the commit
that causes the semantic change) should do the trick.

BR,
Pavel
--
People of Russia, stop Putin before his war on Ukraine escalates.

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