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>>>> memblocks_present(); >>>> >>>> + if (compound_info_has_mask()) { >>>> + unsigned long alignment; >>>> + bool aligned; >>>> + >>>> + alignment = MAX_FOLIO_NR_PAGES * sizeof(struct page); >>>> + aligned = IS_ALIGNED((unsigned long) pfn_to_page(0), alignment); >>>> + >>>> + if (IS_ENABLED(CONFIG_DEBUG_VM)) >>>> + BUG_ON(!aligned); >>>> + else >>>> + WARN_ON(!aligned); >>> >>> Since you’ve fixed all the problematic architectures, I don’t believe >>> we’ll ever hit the WARN or BUG here anymore. >>> >>> I think we can now simplify the code further and just use VM_BUG_ON: >>> if any architecture changes in the future, the misalignment will be >>> caught during testing, so we won’t need to worry about it at run-time. >>> >> >> VM_WARN_ON should be sufficient, since bots should report warnings >> from any patch/change. > > I’m not sure a WARN will get developers’ attention, since the message > is unlikely to have any visible consequences and only fires on > allocations with a special order. If a developer misses the WARN and the patch gets into linux-mm or linux-next, kernel test robot runs selftests on the kernel and reports any warnings to the mailing list. Do we have any related test in selftests/mm? That should help us catch anything if a developer does not catch it. Best Regards, Yan, Zi