Re: [PATCH 1/1] mm,swapops: Fix compile error on set_pmd_migration_entry.

[wale zhang <wale.zhang.ftd@gmail.com>]

On Tue, Dec 30, 2025 at 1:00 PM Matthew Wilcox <willy@infradead.org> wrote:
>
> On Fri, Dec 26, 2025 at 07:45:48PM +0800, wale zhang wrote:
> > I compile the 6.19-rc2 for arm64 with -O0, this kind of error log will appear.
>
> I don't think we support compilation with -O0.  Why did you think this
> would work, and why did you think this was a good idea?

Hello Matthew,

Compilation with -O0 is mainly for beginners to learn and debug.
I don't want to encounter the same problems every time I pull the
latest code. Perhaps other people will also encounter the same
problem.

And I see that include/linux/pgtable.h has the same usage.
 320 static inline int pmdp_set_access_flags(struct vm_area_struct *vma,
 321                                         unsigned long address, pmd_t *pmdp,
 322                                         pmd_t entry, int dirty)
 323 {
 324         BUILD_BUG();
 325         return 0;
 326 }

Thanks
Wale