From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Leizhen (ThunderTown)" Subject: Re: [PATCH v7 09/14] arm64/numa: support HAVE_SETUP_PER_CPU_AREA Date: Sat, 27 Aug 2016 18:06:09 +0800 Message-ID: <57C16611.1040206@huawei.com> References: <1472024693-12912-1-git-send-email-thunder.leizhen@huawei.com> <1472024693-12912-10-git-send-email-thunder.leizhen@huawei.com> <20160826132838.GE30302@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160826132838.GE30302-5wv7dgnIgG8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Will Deacon Cc: Catalin Marinas , linux-arm-kernel , linux-kernel , Rob Herring , Frank Rowand , devicetree , Zefan Li , Xinwei Hu , Tianhong Ding , Hanjun Guo List-Id: devicetree@vger.kernel.org On 2016/8/26 21:28, Will Deacon wrote: > On Wed, Aug 24, 2016 at 03:44:48PM +0800, Zhen Lei wrote: >> To make each percpu area allocated from its local numa node. Without this >> patch, all percpu areas will be allocated from the node which cpu0 belongs >> to. >> >> Signed-off-by: Zhen Lei >> --- >> arch/arm64/Kconfig | 8 ++++++++ >> arch/arm64/mm/numa.c | 55 ++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 2 files changed, 63 insertions(+) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index bc3f00f..2815af6 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -603,6 +603,14 @@ config USE_PERCPU_NUMA_NODE_ID >> def_bool y >> depends on NUMA >> >> +config HAVE_SETUP_PER_CPU_AREA >> + def_bool y >> + depends on NUMA >> + >> +config NEED_PER_CPU_EMBED_FIRST_CHUNK >> + def_bool y >> + depends on NUMA > > Why do we need this? Is it purely about using block mappings for the > pcpu area? Without NEED_PER_CPU_EMBED_FIRST_CHUNK, Link error will be reported. #if defined(CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK) || \ !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA) #define BUILD_EMBED_FIRST_CHUNK #endif #if defined(BUILD_EMBED_FIRST_CHUNK) //pcpu_embed_first_chunk definition #endif setup_per_cpu_areas -->pcpu_embed_first_chunk > >> source kernel/Kconfig.preempt >> source kernel/Kconfig.hz >> >> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c >> index 7b73808..5e44ad1 100644 >> --- a/arch/arm64/mm/numa.c >> +++ b/arch/arm64/mm/numa.c >> @@ -26,6 +26,7 @@ >> #include >> >> #include >> +#include >> >> struct pglist_data *node_data[MAX_NUMNODES] __read_mostly; >> EXPORT_SYMBOL(node_data); >> @@ -131,6 +132,60 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid) >> cpu_to_node_map[cpu] = nid; >> } >> >> +#ifdef CONFIG_HAVE_SETUP_PER_CPU_AREA >> +unsigned long __per_cpu_offset[NR_CPUS] __read_mostly; >> +EXPORT_SYMBOL(__per_cpu_offset); >> + >> +static int __init early_cpu_to_node(int cpu) >> +{ >> + return cpu_to_node_map[cpu]; >> +} >> + >> +static int __init pcpu_cpu_distance(unsigned int from, unsigned int to) >> +{ >> + if (early_cpu_to_node(from) == early_cpu_to_node(to)) >> + return LOCAL_DISTANCE; >> + else >> + return REMOTE_DISTANCE; >> +} > > Is it too early to use __node_distance here? Good, we can directly use node_distance, thanks. > >> +static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, >> + size_t align) >> +{ >> + int nid = early_cpu_to_node(cpu); >> + >> + return memblock_virt_alloc_try_nid(size, align, >> + __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, nid); >> +} >> + >> +static void __init pcpu_fc_free(void *ptr, size_t size) >> +{ >> + memblock_free_early(__pa(ptr), size); >> +} >> + >> +void __init setup_per_cpu_areas(void) >> +{ >> + unsigned long delta; >> + unsigned int cpu; >> + int rc; >> + >> + /* >> + * Always reserve area for module percpu variables. That's >> + * what the legacy allocator did. >> + */ >> + rc = pcpu_embed_first_chunk(PERCPU_MODULE_RESERVE, >> + PERCPU_DYNAMIC_RESERVE, PAGE_SIZE, >> + pcpu_cpu_distance, >> + pcpu_fc_alloc, pcpu_fc_free); >> + if (rc < 0) >> + panic("Failed to initialize percpu areas."); >> + >> + delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start; >> + for_each_possible_cpu(cpu) >> + __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu]; >> +} >> +#endif > > It's a pity that this is practically identical to PowerPC. Ideally, there > would be definitions of this initialisation gunk in the core code that > could be reused across architectures. But these are different from other ARCHs, except PPC. I originally want to put it into driver/of/of_numa.c, but now the ACPI NUMA is coming up, so I don't known where. > > Will > > . > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html