On Thu, Jun 18, 2020 at 07:43:43AM +0000, Song Bao Hua (Barry Song) wrote: > > > > -----Original Message----- > > From: Will Deacon [mailto:w...@kernel.org] > > Sent: Thursday, June 18, 2020 7:20 PM > > To: Song Bao Hua (Barry Song) <song.bao....@hisilicon.com> > > Cc: Roman Gushchin <g...@fb.com>; catalin.mari...@arm.com; > > nsaenzjulie...@suse.de; steve.cap...@arm.com; r...@linux.ibm.com; > > a...@linux-foundation.org; linux-arm-ker...@lists.infradead.org; > > linux-kernel@vger.kernel.org; Linuxarm <linux...@huawei.com>; Matthias > > Brugger <matthias....@gmail.com> > > Subject: Re: [PATCH v2] arm64: mm: reserve hugetlb CMA after numa_init > > > > On Wed, Jun 17, 2020 at 09:43:51PM +0000, Song Bao Hua (Barry Song) > > wrote: > > > > From: Roman Gushchin [mailto:g...@fb.com] > > > > On Wed, Jun 17, 2020 at 11:38:03AM +0000, Song Bao Hua (Barry Song) > > > > > > From: Will Deacon [mailto:w...@kernel.org] > > > > > > On Wed, Jun 17, 2020 at 10:19:24AM +1200, Barry Song wrote: > > > > > > > hugetlb_cma_reserve() is called at the wrong place. numa_init has > > > > > > > not > > > > > > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > > > > > > > index e631e6425165..41914b483d54 100644 > > > > > > > --- a/arch/arm64/mm/init.c > > > > > > > +++ b/arch/arm64/mm/init.c > > > > > > > @@ -404,11 +404,6 @@ void __init arm64_memblock_init(void) > > > > > > > high_memory = __va(memblock_end_of_DRAM() - 1) + 1; > > > > > > > > > > > > > > dma_contiguous_reserve(arm64_dma32_phys_limit); > > > > > > > - > > > > > > > -#ifdef CONFIG_ARM64_4K_PAGES > > > > > > > - hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT); > > > > > > > -#endif > > > > > > > > > > > > Why is this dependent on CONFIG_ARM64_4K_PAGES? We > > unconditionally > > > > > > select ARCH_HAS_GIGANTIC_PAGE so this seems unnecessary. > > > > > > > > > > Roman, would you like to answer this question? Have you found any > > > > problem if system > > > > > doesn't set 4K_PAGES? > > > > > > > > No, I was just following the code in arch/arm64/mm/hugetlbpage.c where > > all > > > > related to PUD-sized pages is guarded by CONFIG_ARM64_4K_PAGES. > > > > Actually I did all my testing on x86-64, I don't even have any arm > > hardware. > > > > > > > > I'm totally fine with removing this #ifdef if it's not needed. > > > > > > At this moment, I would suggest we should keep this "ifdef". Otherwise, > > hugetlb_cma_reserve() won't be really useful. > > > > > > For example, while setting PAGE size to 64KB. I got this error in > > hugetlb_cma_reserve(): > > > hugetlb_cma: cma area should be at least 4194304 MiB > > > This is absolutely unreasonable. > > > > Maybe one for RaspberryPi 5, huh? ;) > > > > But ok, I'll take your patch as-is and add a comment about NUMA. > > Have you seen the v3 with comment? I've already sent.
Thanks, just saw that (I'm going through morning email atm :) Will
