Re: [PATCH v3 05/11] arm64: hugetlb: Use set_ptes_anysz() and ptep_get_and_clear_anysz()

[Ryan Roberts]

On 05/03/2025 16:00, kernel test robot wrote:
> Hi Ryan,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on linus/master]
> [also build test WARNING on v6.14-rc5 next-20250305]
> [cannot apply to arm64/for-next/core akpm-mm/mm-everything arm-perf/for-next/perf]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Ryan-Roberts/arm64-hugetlb-Cleanup-huge_pte-size-discovery-mechanisms/20250304-230647
> base:   linus/master
> patch link:    https://lore.kernel.org/r/20250304150444.3788920-6-ryan.roberts%40arm.com
> patch subject: [PATCH v3 05/11] arm64: hugetlb: Use set_ptes_anysz() and ptep_get_and_clear_anysz()
> config: arm64-randconfig-003-20250305 (https://download.01.org/0day-ci/archive/20250305/202503052315.vk7m958M-lkp@xxxxxxxxx/config)
> compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 14170b16028c087ca154878f5ed93d3089a965c6)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250305/202503052315.vk7m958M-lkp@xxxxxxxxx/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202503052315.vk7m958M-lkp@xxxxxxxxx/
> 
> All warnings (new ones prefixed by >>):
> 
>    In file included from arch/arm64/mm/hugetlbpage.c:12:
>    In file included from include/linux/mm.h:2224:
>    include/linux/vmstat.h:504:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      504 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      505 |                            item];
>          |                            ~~~~
>    include/linux/vmstat.h:511:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      511 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      512 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
>>> arch/arm64/mm/hugetlbpage.c:154:23: warning: parameter 'addr' set but not used [-Wunused-but-set-parameter]
>      154 |                              unsigned long addr,
>          |                                            ^
>    3 warnings generated.
> 
> 
> vim +/addr +154 arch/arm64/mm/hugetlbpage.c
> 
> bc5dfb4fd7bd471 Baolin Wang       2022-05-16  144  
> d8bdcff2876424d Steve Capper      2017-08-22  145  /*
> d8bdcff2876424d Steve Capper      2017-08-22  146   * Changing some bits of contiguous entries requires us to follow a
> d8bdcff2876424d Steve Capper      2017-08-22  147   * Break-Before-Make approach, breaking the whole contiguous set
> d8bdcff2876424d Steve Capper      2017-08-22  148   * before we can change any entries. See ARM DDI 0487A.k_iss10775,
> d8bdcff2876424d Steve Capper      2017-08-22  149   * "Misprogramming of the Contiguous bit", page D4-1762.
> d8bdcff2876424d Steve Capper      2017-08-22  150   *
> d8bdcff2876424d Steve Capper      2017-08-22  151   * This helper performs the break step.
> d8bdcff2876424d Steve Capper      2017-08-22  152   */
> fb396bb459c1fa3 Anshuman Khandual 2022-05-10  153  static pte_t get_clear_contig(struct mm_struct *mm,
> d8bdcff2876424d Steve Capper      2017-08-22 @154  			     unsigned long addr,
> d8bdcff2876424d Steve Capper      2017-08-22  155  			     pte_t *ptep,
> d8bdcff2876424d Steve Capper      2017-08-22  156  			     unsigned long pgsize,
> d8bdcff2876424d Steve Capper      2017-08-22  157  			     unsigned long ncontig)
> d8bdcff2876424d Steve Capper      2017-08-22  158  {
> 49c87f7677746f3 Ryan Roberts      2025-02-26  159  	pte_t pte, tmp_pte;
> 49c87f7677746f3 Ryan Roberts      2025-02-26  160  	bool present;
> 49c87f7677746f3 Ryan Roberts      2025-02-26  161  
> 66251d3eadf78e2 Ryan Roberts      2025-03-04  162  	pte = ptep_get_and_clear_anysz(mm, ptep, pgsize);
> 49c87f7677746f3 Ryan Roberts      2025-02-26  163  	present = pte_present(pte);
> 49c87f7677746f3 Ryan Roberts      2025-02-26  164  	while (--ncontig) {
> 49c87f7677746f3 Ryan Roberts      2025-02-26  165  		ptep++;
> 49c87f7677746f3 Ryan Roberts      2025-02-26  166  		addr += pgsize;

Ahh yes, thanks! Looks like this line can be removed since we no longer need the
address.

Catalin, I was optimistically hoping this might be the final version. If it is,
are you happy to fold this in? Or do you want me to re-spin regardless?

> 66251d3eadf78e2 Ryan Roberts      2025-03-04  167  		tmp_pte = ptep_get_and_clear_anysz(mm, ptep, pgsize);
> 49c87f7677746f3 Ryan Roberts      2025-02-26  168  		if (present) {
> 49c87f7677746f3 Ryan Roberts      2025-02-26  169  			if (pte_dirty(tmp_pte))
> 49c87f7677746f3 Ryan Roberts      2025-02-26  170  				pte = pte_mkdirty(pte);
> 49c87f7677746f3 Ryan Roberts      2025-02-26  171  			if (pte_young(tmp_pte))
> 49c87f7677746f3 Ryan Roberts      2025-02-26  172  				pte = pte_mkyoung(pte);
> d8bdcff2876424d Steve Capper      2017-08-22  173  		}
> 49c87f7677746f3 Ryan Roberts      2025-02-26  174  	}
> 49c87f7677746f3 Ryan Roberts      2025-02-26  175  	return pte;
> d8bdcff2876424d Steve Capper      2017-08-22  176  }
> d8bdcff2876424d Steve Capper      2017-08-22  177  
>