Messages in this thread | | | Date | Tue, 29 Mar 2022 15:29:41 -0700 | Subject | Re: [PATCH 1/2] arm64: mm: Do not defer reserve_crashkernel() if only ZONE_DMA32 | From | Vijay Balakrishna <> |
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On 3/24/2022 10:53 PM, Kefeng Wang wrote: > The kernel could be benifit due to BLOCK_MAPPINGS, see commit > 031495635b46 ("arm64: Do not defer reserve_crashkernel() for > platforms with no DMA memory zones"), if there is only with > ZONE_DMA32, we could set arm64_dma_phys_limit to max_zone_phys(32) > earlier in arm64_memblock_init(), then we will benifit too.
Thanks for noticing platforms with just ZONE_DMA32 config can also benefit BLOCK_MAPPINGS. I assume you have access to one where you notice the difference with proposed changes and able to test. I did test proposed changes on SoC we use with IOMMU (no ZONE_DMA configs enabled).
Nits -- - benifit -> benefit - consider making commit message clear, "then we will.." seems you are referring to platforms with just ZONE_DMA32 config enabled - to reflect new change consider updating comment added in commit 031495635b46
> > Cc: Vijay Balakrishna <vijayb@linux.microsoft.com> > Cc: Pasha Tatashin <pasha.tatashin@soleen.com> > Cc: Will Deacon <will@kernel.org> > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vijay Balakrishna <vijayb@linux.microsoft.com>
> --- > arch/arm64/mm/init.c | 18 ++++++++++-------- > arch/arm64/mm/mmu.c | 6 ++---- > 2 files changed, 12 insertions(+), 12 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 8ac25f19084e..9dded8779d72 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -157,14 +157,14 @@ static phys_addr_t __init max_zone_phys(unsigned int zone_bits) > return min(zone_mask, memblock_end_of_DRAM() - 1) + 1; > } > > +phys_addr_t __ro_after_init dma32_phys_limit; > static void __init zone_sizes_init(unsigned long min, unsigned long max) > { > unsigned long max_zone_pfns[MAX_NR_ZONES] = {0}; > - unsigned int __maybe_unused acpi_zone_dma_bits; > - unsigned int __maybe_unused dt_zone_dma_bits; > - phys_addr_t __maybe_unused dma32_phys_limit = max_zone_phys(32); > - > #ifdef CONFIG_ZONE_DMA > + unsigned int acpi_zone_dma_bits; > + unsigned int dt_zone_dma_bits; > + > acpi_zone_dma_bits = fls64(acpi_iort_dma_get_max_cpu_address()); > dt_zone_dma_bits = fls64(of_dma_get_max_cpu_address(NULL)); > zone_dma_bits = min3(32U, dt_zone_dma_bits, acpi_zone_dma_bits); > @@ -173,8 +173,6 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max) > #endif > #ifdef CONFIG_ZONE_DMA32 > max_zone_pfns[ZONE_DMA32] = PFN_DOWN(dma32_phys_limit); > - if (!arm64_dma_phys_limit) > - arm64_dma_phys_limit = dma32_phys_limit; > #endif > max_zone_pfns[ZONE_NORMAL] = max; > > @@ -336,8 +334,12 @@ void __init arm64_memblock_init(void) > > early_init_fdt_scan_reserved_mem(); > > - if (!IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) > + dma32_phys_limit = max_zone_phys(32); > + if (!IS_ENABLED(CONFIG_ZONE_DMA)) { > + if (IS_ENABLED(CONFIG_ZONE_DMA32)) > + arm64_dma_phys_limit = dma32_phys_limit; > reserve_crashkernel(); > + } > > high_memory = __va(memblock_end_of_DRAM() - 1) + 1; > } > @@ -385,7 +387,7 @@ void __init bootmem_init(void) > * request_standard_resources() depends on crashkernel's memory being > * reserved, so do it here. > */ > - if (IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32)) > + if (IS_ENABLED(CONFIG_ZONE_DMA)) > reserve_crashkernel(); > > memblock_dump_all(); > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 626ec32873c6..23734481318a 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -529,8 +529,7 @@ static void __init map_mem(pgd_t *pgdp) > > #ifdef CONFIG_KEXEC_CORE > if (crash_mem_map) { > - if (IS_ENABLED(CONFIG_ZONE_DMA) || > - IS_ENABLED(CONFIG_ZONE_DMA32)) > + if (IS_ENABLED(CONFIG_ZONE_DMA)) > flags |= NO_BLOCK_MAPPINGS | NO_CONT_MAPPINGS; > else if (crashk_res.end) > memblock_mark_nomap(crashk_res.start, > @@ -571,8 +570,7 @@ static void __init map_mem(pgd_t *pgdp) > * through /sys/kernel/kexec_crash_size interface. > */ > #ifdef CONFIG_KEXEC_CORE > - if (crash_mem_map && > - !IS_ENABLED(CONFIG_ZONE_DMA) && !IS_ENABLED(CONFIG_ZONE_DMA32)) { > + if (crash_mem_map && !IS_ENABLED(CONFIG_ZONE_DMA)) { > if (crashk_res.end) { > __map_memblock(pgdp, crashk_res.start, > crashk_res.end + 1,
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