Re: [Crash-utility] [PATCH] arm64: handle 1GB block

在 2021年04月16日 17:25, Johan.Erlandsson(a)sony.com 写道: > Hi Lianbo > >>> >>> With enough continuous physical memory we can have 1GB block. This have >>> been seen only in linear mapping region in kernel space. I have only >>> verified this for VM_L3_4K. >>> >>> reference: alloc_init_pud(), use_1G_block() [arch/arm64/mm/mmu.c] >>> >> For this situation, do you know how to reproduce it easily? Can you share >> your steps in detail? > > I can try, one requirement is that you have memory aligned at 1 GB and > size is at least 1 GB. Lets assume we have vmcore with physical memory > at 0x100000000 (1 GB aligned) with size at least 1 GB. Then from crash we > could do: > Thank you for the explanation, Johan. I will try to reproduce it later, but anyway, this patch and test are good to me. Acked-by: Lianbo Jiang <lijiang(a)redhat.com&gt;

> crash> ptov 100000000 > VIRTUAL PHYSICAL > ffffffe900000000 100000000 > > crash> vtop ffffffe900000000 > VIRTUAL PHYSICAL > ffffffe900000000 100000000 > > PAGE DIRECTORY: ffffff990f66c000 > PGD: ffffff990f66cd20 => 68000100000711 > PAGE: 100000000 (1GB) > > PTE PHYSICAL FLAGS > 68000100000711 100000000 (VALID|SHARED|AF|PXN|UXN) > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > ffffffbfa4000000 100000000 ffffffe97de59090 fe 2 20054 uptodate,lru,workingset,mappedtodisk > > I hope that helps. > Yes, it certainly helps. Thanks Lianbo > Regards > Johan > >> BTW: I did the test, but I didn't enter into the kernel code path because >> that condition was not met. >> >> # dmesg|grep -i huge >> [ 0.000000] Kernel command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.12.0-rc7+ root=/dev/mapper/rhel_gigabyte--r120--20-root ro arm->smmu.disable_bypass=n initcall_blacklist=gtdt_sbsa_gwdt_init iommu.passthrough=1 crashkernel=512M hugepagesz=1G hugepages=6 >debug_pagealloc=on rd.lvm.lv=rhel_gigabyte-r120-20/root rd.lvm.lv=rhel_gigabyte-r120-20/swap >> [ 2.620634] HugeTLB registered 1.00 GiB page size, pre-allocated 6 pages >> >> Thanks. >> Lianbo > > >