Hi! > > > For architectures with CONFIG_ARCH_HAS_SET_ALIAS, pages can be unmapped > > > briefly on the directmap, even when CONFIG_DEBUG_PAGEALLOC is not > > > configured. > > > So this changes kernel_map_pages and kernel_page_present to be defined > > > when > > > CONFIG_ARCH_HAS_SET_ALIAS is defined as well. It also changes places > > > (page_alloc.c) where those functions are assumed to only be implemented > > > when > > > CONFIG_DEBUG_PAGEALLOC is defined. > > > > Which architectures are that? > > > > Should this be merged to the patch where HAS_SET_ALIAS is introduced? We > > don't want broken hibernation in between.... > Thanks for taking a look. It was added for x86 for patch 13 in this patchset > and > there was interest expressed for adding for arm64. If you didn't get the whole > set and want to see let me know and I can send it.
I googled in in the meantime.
Anyway, if something is broken between patch 13 and 14, then they
should be same patch.
> > > -#ifdef CONFIG_DEBUG_PAGEALLOC
> > > extern bool _debug_pagealloc_enabled;
> > > -extern void __kernel_map_pages(struct page *page, int numpages, int
> > > enable);
> > >
> > > static inline bool debug_pagealloc_enabled(void)
> > > {
> > > - return _debug_pagealloc_enabled;
> > > + return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && _debug_pagealloc_enabled;
> > > }
> >
> > This will break build AFAICT. _debug_pagealloc_enabled variable does
> > not exist in !CONFIG_DEBUG_PAGEALLOC case.
> >
> > Pavel
> After adding in the CONFIG_ARCH_HAS_SET_ALIAS condition to the ifdefs in this
> area it looked a little hard to read to me, so I moved debug_pagealloc_enabled
> and extern bool _debug_pagealloc_enabled outside to make it easier. I think
> you
> are right, the actual non-extern variable can not be there, but the reference
> here gets optimized out in that case.
>
> Just double checked and it builds for both CONFIG_DEBUG_PAGEALLOC=n and
> CONFIG_DEBUG_PAGEALLOC=y for me.
Ok.
Thanks,
Pavel
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