Messages in this thread | | | Date | Mon, 11 Apr 2022 16:28:14 +0800 | Subject | Re: [PATCH v2 resend 2/3] arm64: mm: Don't defer reserve_crashkernel() with dma_force_32bit | From | Kefeng Wang <> |
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On 2022/4/2 6:09, Vijay Balakrishna wrote: > > > On 3/31/2022 12:40 AM, Kefeng Wang wrote: >> ARM64 enable ZONE_DMA by default, and with ZONE_DMA crash kernel >> memory reservation is delayed until DMA zone memory range size >> initilazation performed in zone_sizes_init(), but for most platforms >> use 32bit dma_zone_bits, so add dma_force_32bit kernel parameter >> if ZONE_DMA enabled, and initialize arm64_dma_phys_limit to >> dma32_phys_limit in arm64_memblock_init() if dma_force_32bit >> is setup, this could let the crash kernel reservation earlier, >> and allows linear creation with block mapping. >> >> Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > > I don't see any problem with the approach. Hope you or someone can > test to make sure no surprises on RPi4 with the proposed change. I do > understand on RPi4 -- > > - both ZONE_DMA and ZONE_DMA32 are enabled > - one wouldn't use dma_force_32bit kernel parameter > - crashkernel_could_early_reserve() would return false to preserve > late reserve of crash kernel memory > I don't have RPi4, I tested following cases on qemu
1) only with ZONE_DMA
1.1) only with ZONE_DMA and with dma_force_32bit
2) only with ZONE_DMA32
3) with ZONE_DMA and ZONE_DMA32
3.1) with ZONE_DMA and ZONE_DMA32 and with dma_force_32bit
> nit -- > - consider renaming crashkernel_could_early_reserve() => > crashkernel_early_reserve() > Sure. > Reviewed-by: Vijay Balakrishna <vijayb@linux.microsoft.com> > Thanks.
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