On Wed, Jun 30, 2021 at 05:23:09PM +0800, Miles Chen wrote: > clarify pgdat_to_phys() by wrapping pgdat_to_phys > with CONFIG_NUMA. (the same config as contig_page_data) > > No functional change intended. > > Comment from Mark [1]: > " > ... and I reckon it'd be clearer and more robust to define > pgdat_to_phys() in the same ifdefs as contig_page_data so > that these, stay in-sync. e.g. have: > > | #ifdef CONFIG_NUMA > | #define pgdat_to_phys(x) virt_to_phys(x) > | #else /* CONFIG_NUMA */ > | > | extern struct pglist_data contig_page_data; > | ... > | #define pgdat_to_phys(x) __pa_symbol(&contig_page_data) > | > | #endif /* CONIFIG_NUMA */ > " > > [1] https://lore.kernel.org/linux-arm-kernel/20210615131902.GB47121@C02TD0UTHF1T.local/ > > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx> > --- > mm/sparse.c | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/mm/sparse.c b/mm/sparse.c > index 7272f7a1449d..62c21ec28e33 100644 > --- a/mm/sparse.c > +++ b/mm/sparse.c > @@ -344,14 +344,15 @@ size_t mem_section_usage_size(void) > return sizeof(struct mem_section_usage) + usemap_size(); > } > > -static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat) > -{ > -#ifndef CONFIG_NUMA > - return __pa_symbol(pgdat); > -#else > - return __pa(pgdat); > -#endif > -} > +#ifdef CONFIG_NUMA > +#define pgdat_to_phys(pgdat) __pa(pgdat) > +#else /* CONFIG_NUMA */ > +/* > + * When !CONFIG_NUMA, we only expect pgdat == &contig_page_data, > + * and use __pa_symbol(). > + */ > +#define pgdat_to_phys(pgdat) __pa_symbol(pgdat) > +#endif /* CONFIG_NUMA */ I'm not sure a macro is better than a static inline. Maybe we'd want to warn if pgdat passed to pgtat_to_phys() is not &contig_page_data, e.g something like static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat) { if (!IS_ENABLED(CONFIG_NUMA)) { if (pgdat == &contig_page_data) return __pa_symbol(&contig_page_data); else pr_warn("Unexpected pglist_data pointer!\n"); } return __pa(pgdat); } > #ifdef CONFIG_MEMORY_HOTREMOVE > static struct mem_section_usage * __init > -- > 2.18.0 > -- Sincerely yours, Mike.
