Messages in this thread | | | Date | Fri, 1 Apr 2022 08:59:24 -0700 | Subject | Re: [PATCH v2 resend 1/3] arm64: mm: Do not defer reserve_crashkernel() if only ZONE_DMA32 | From | Vijay Balakrishna <> |
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On 3/31/2022 12:40 AM, Kefeng Wang wrote: > The kernel could be benefit due to BLOCK_MAPPINGS, see commit > 031495635b46 ("arm64: Do not defer reserve_crashkernel() for > platforms with no DMA memory zones"), if only with ZONE_DMA32, > set arm64_dma_phys_limit to max_zone_phys(32) earlier in > arm64_memblock_init(), so platforms with just ZONE_DMA32 config > enabled will be benefit.
nit -- - "will be benefit" => will benefit
On further look I feel we can getaway without dma32_phys_limit static global and replace with two separate calls to max_zone_phys(32)? Just a thought. If you decide to keep it then a better location would be immediately above arm64_memblock_init() definition where it is initialized can improve code readability.
Thanks, Vijay
> > Cc: Vijay Balakrishna <vijayb@linux.microsoft.com> > Cc: Pasha Tatashin <pasha.tatashin@soleen.com> > Cc: Will Deacon <will@kernel.org> > Reviewed-by: Vijay Balakrishna <vijayb@linux.microsoft.com> > Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> > --- > arch/arm64/mm/init.c | 23 +++++++++++++---------- > arch/arm64/mm/mmu.c | 6 ++---- > 2 files changed, 15 insertions(+), 14 deletions(-) > > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 8ac25f19084e..fb01eb489fa9 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -65,8 +65,9 @@ EXPORT_SYMBOL(memstart_addr); > * Memory reservation for crash kernel either done early or deferred > * depending on DMA memory zones configs (ZONE_DMA) -- > * > - * In absence of ZONE_DMA configs arm64_dma_phys_limit initialized > - * here instead of max_zone_phys(). This lets early reservation of > + * In absence of ZONE_DMA and ZONE_DMA32 configs arm64_dma_phys_limit > + * initialized here and if only with ZONE_DMA32 arm64_dma_phys_limit > + * initialised to dma32_phys_limit. This lets early reservation of > * crash kernel memory which has a dependency on arm64_dma_phys_limit. > * Reserving memory early for crash kernel allows linear creation of block > * mappings (greater than page-granularity) for all the memory bank rangs. > @@ -84,6 +85,7 @@ EXPORT_SYMBOL(memstart_addr); > * Note: Page-granularity mapppings are necessary for crash kernel memory > * range for shrinking its size via /sys/kernel/kexec_crash_size interface. > */ > +static phys_addr_t __ro_after_init dma32_phys_limit;
> #if IS_ENABLED(CONFIG_ZONE_DMA) || IS_ENABLED(CONFIG_ZONE_DMA32) > phys_addr_t __ro_after_init arm64_dma_phys_limit; > #else > @@ -160,11 +162,10 @@ static phys_addr_t __init max_zone_phys(unsigned int zone_bits) > 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 +174,6 @@ 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 +335,12 @@ 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 +388,7 @@ 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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