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Date:   Wed, 29 Sep 2021 09:25:52 -0700
From:   Mike Rapoport <rppt@kernel.org>
To:     David Hildenbrand <david@redhat.com>
Cc:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Oscar Salvador <osalvador@suse.de>,
        Jianyong Wu <Jianyong.Wu@arm.com>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        Vineet Gupta <vgupta@kernel.org>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Huacai Chen <chenhuacai@kernel.org>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        Eric Biederman <ebiederm@xmission.com>,
        Arnd Bergmann <arnd@arndb.de>,
        linux-snps-arc@lists.infradead.org, linux-ia64@vger.kernel.org,
        linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org,
        linux-s390@vger.kernel.org, linux-mm@kvack.org,
        kexec@lists.infradead.org
Subject: Re: [PATCH v1 2/4] memblock: allow to specify flags with
 memblock_add_node()
Message-ID: <YVSTkGdh2nQWQp+U@kernel.org>
References: <20210927150518.8607-1-david@redhat.com>
 <20210927150518.8607-3-david@redhat.com>
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In-Reply-To: <20210927150518.8607-3-david@redhat.com>
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On Mon, Sep 27, 2021 at 05:05:16PM +0200, David Hildenbrand wrote:
> We want to specify flags when hotplugging memory. Let's prepare to pass
> flags to memblock_add_node() by adjusting all existing users.
> 
> Note that when hotplugging memory the system is already up and running
> and we don't want to add the memory first and apply flags later: it
> should happen within one memblock call.

Why is it important that the system is up and why it should happen in a
single call?
I don't mind adding flags parameter to memblock_add_node() but this
changelog does not really explain the reasons to do it.
 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  arch/arc/mm/init.c               | 4 ++--
>  arch/ia64/mm/contig.c            | 2 +-
>  arch/ia64/mm/init.c              | 2 +-
>  arch/m68k/mm/mcfmmu.c            | 3 ++-
>  arch/m68k/mm/motorola.c          | 6 ++++--
>  arch/mips/loongson64/init.c      | 4 +++-
>  arch/mips/sgi-ip27/ip27-memory.c | 3 ++-
>  arch/s390/kernel/setup.c         | 3 ++-
>  include/linux/memblock.h         | 3 ++-
>  include/linux/mm.h               | 2 +-
>  mm/memblock.c                    | 9 +++++----
>  mm/memory_hotplug.c              | 2 +-
>  12 files changed, 26 insertions(+), 17 deletions(-)
> 
> diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
> index 699ecf119641..110eb69e9bee 100644
> --- a/arch/arc/mm/init.c
> +++ b/arch/arc/mm/init.c
> @@ -59,13 +59,13 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size)
>  
>  		low_mem_sz = size;
>  		in_use = 1;
> -		memblock_add_node(base, size, 0);
> +		memblock_add_node(base, size, 0, MEMBLOCK_NONE);
>  	} else {
>  #ifdef CONFIG_HIGHMEM
>  		high_mem_start = base;
>  		high_mem_sz = size;
>  		in_use = 1;
> -		memblock_add_node(base, size, 1);
> +		memblock_add_node(base, size, 1, MEMBLOCK_NONE);
>  		memblock_reserve(base, size);
>  #endif
>  	}
> diff --git a/arch/ia64/mm/contig.c b/arch/ia64/mm/contig.c
> index 42e025cfbd08..24901d809301 100644
> --- a/arch/ia64/mm/contig.c
> +++ b/arch/ia64/mm/contig.c
> @@ -153,7 +153,7 @@ find_memory (void)
>  	efi_memmap_walk(find_max_min_low_pfn, NULL);
>  	max_pfn = max_low_pfn;
>  
> -	memblock_add_node(0, PFN_PHYS(max_low_pfn), 0);
> +	memblock_add_node(0, PFN_PHYS(max_low_pfn), 0, MEMBLOCK_NONE);
>  
>  	find_initrd();
>  
> diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c
> index 5c6da8d83c1a..5d165607bf35 100644
> --- a/arch/ia64/mm/init.c
> +++ b/arch/ia64/mm/init.c
> @@ -378,7 +378,7 @@ int __init register_active_ranges(u64 start, u64 len, int nid)
>  #endif
>  
>  	if (start < end)
> -		memblock_add_node(__pa(start), end - start, nid);
> +		memblock_add_node(__pa(start), end - start, nid, MEMBLOCK_NONE);
>  	return 0;
>  }
>  
> diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
> index eac9dde65193..6f1f25125294 100644
> --- a/arch/m68k/mm/mcfmmu.c
> +++ b/arch/m68k/mm/mcfmmu.c
> @@ -174,7 +174,8 @@ void __init cf_bootmem_alloc(void)
>  	m68k_memory[0].addr = _rambase;
>  	m68k_memory[0].size = _ramend - _rambase;
>  
> -	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
> +	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
> +			  MEMBLOCK_NONE);
>  
>  	/* compute total pages in system */
>  	num_pages = PFN_DOWN(_ramend - _rambase);
> diff --git a/arch/m68k/mm/motorola.c b/arch/m68k/mm/motorola.c
> index 3a653f0a4188..e80c5d7e6728 100644
> --- a/arch/m68k/mm/motorola.c
> +++ b/arch/m68k/mm/motorola.c
> @@ -410,7 +410,8 @@ void __init paging_init(void)
>  
>  	min_addr = m68k_memory[0].addr;
>  	max_addr = min_addr + m68k_memory[0].size;
> -	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0);
> +	memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
> +			  MEMBLOCK_NONE);
>  	for (i = 1; i < m68k_num_memory;) {
>  		if (m68k_memory[i].addr < min_addr) {
>  			printk("Ignoring memory chunk at 0x%lx:0x%lx before the first chunk\n",
> @@ -421,7 +422,8 @@ void __init paging_init(void)
>  				(m68k_num_memory - i) * sizeof(struct m68k_mem_info));
>  			continue;
>  		}
> -		memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i);
> +		memblock_add_node(m68k_memory[i].addr, m68k_memory[i].size, i,
> +				  MEMBLOCK_NONE);
>  		addr = m68k_memory[i].addr + m68k_memory[i].size;
>  		if (addr > max_addr)
>  			max_addr = addr;
> diff --git a/arch/mips/loongson64/init.c b/arch/mips/loongson64/init.c
> index 76e0a9636a0e..4ac5ba80bbf6 100644
> --- a/arch/mips/loongson64/init.c
> +++ b/arch/mips/loongson64/init.c
> @@ -77,7 +77,9 @@ void __init szmem(unsigned int node)
>  				(u32)node_id, mem_type, mem_start, mem_size);
>  			pr_info("       start_pfn:0x%llx, end_pfn:0x%llx, num_physpages:0x%lx\n",
>  				start_pfn, end_pfn, num_physpages);
> -			memblock_add_node(PFN_PHYS(start_pfn), PFN_PHYS(node_psize), node);
> +			memblock_add_node(PFN_PHYS(start_pfn),
> +					  PFN_PHYS(node_psize), node,
> +					  MEMBLOCK_NONE);
>  			break;
>  		case SYSTEM_RAM_RESERVED:
>  			pr_info("Node%d: mem_type:%d, mem_start:0x%llx, mem_size:0x%llx MB\n",
> diff --git a/arch/mips/sgi-ip27/ip27-memory.c b/arch/mips/sgi-ip27/ip27-memory.c
> index 6173684b5aaa..adc2faeecf7c 100644
> --- a/arch/mips/sgi-ip27/ip27-memory.c
> +++ b/arch/mips/sgi-ip27/ip27-memory.c
> @@ -341,7 +341,8 @@ static void __init szmem(void)
>  				continue;
>  			}
>  			memblock_add_node(PFN_PHYS(slot_getbasepfn(node, slot)),
> -					  PFN_PHYS(slot_psize), node);
> +					  PFN_PHYS(slot_psize), node,
> +					  MEMBLOCK_NONE);
>  		}
>  	}
>  }
> diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
> index 67e5fff96ee0..f3943f15af6e 100644
> --- a/arch/s390/kernel/setup.c
> +++ b/arch/s390/kernel/setup.c
> @@ -593,7 +593,8 @@ static void __init setup_resources(void)
>  	 * part of the System RAM resource.
>  	 */
>  	if (crashk_res.end) {
> -		memblock_add_node(crashk_res.start, resource_size(&crashk_res), 0);
> +		memblock_add_node(crashk_res.start, resource_size(&crashk_res),
> +				  0, MEMBLOCK_NONE);
>  		memblock_reserve(crashk_res.start, resource_size(&crashk_res));
>  		insert_resource(&iomem_resource, &crashk_res);
>  	}
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 34de69b3b8ba..b49a58f621bc 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -100,7 +100,8 @@ static inline void memblock_discard(void) {}
>  #endif
>  
>  void memblock_allow_resize(void);
> -int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid);
> +int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid,
> +		      enum memblock_flags flags);
>  int memblock_add(phys_addr_t base, phys_addr_t size);
>  int memblock_remove(phys_addr_t base, phys_addr_t size);
>  int memblock_free(phys_addr_t base, phys_addr_t size);
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 73a52aba448f..0117cb35b212 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2447,7 +2447,7 @@ static inline unsigned long get_num_physpages(void)
>   * unsigned long max_zone_pfns[MAX_NR_ZONES] = {max_dma, max_normal_pfn,
>   * 							 max_highmem_pfn};
>   * for_each_valid_physical_page_range()
> - * 	memblock_add_node(base, size, nid)
> + *	memblock_add_node(base, size, nid, MEMBLOCK_NONE)
>   * free_area_init(max_zone_pfns);
>   */
>  void free_area_init(unsigned long *max_zone_pfn);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 184dcd2e5d99..47a56b223141 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -655,6 +655,7 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>   * @base: base address of the new region
>   * @size: size of the new region
>   * @nid: nid of the new region
> + * @flags: flags of the new region
>   *
>   * Add new memblock region [@base, @base + @size) to the "memory"
>   * type. See memblock_add_range() description for mode details
> @@ -663,14 +664,14 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
>   * 0 on success, -errno on failure.
>   */
>  int __init_memblock memblock_add_node(phys_addr_t base, phys_addr_t size,
> -				       int nid)
> +				      int nid, enum memblock_flags flags)
>  {
>  	phys_addr_t end = base + size - 1;
>  
> -	memblock_dbg("%s: [%pa-%pa] nid=%d %pS\n", __func__,
> -		     &base, &end, nid, (void *)_RET_IP_);
> +	memblock_dbg("%s: [%pa-%pa] nid=%d flags=%x %pS\n", __func__,
> +		     &base, &end, nid, flags, (void *)_RET_IP_);
>  
> -	return memblock_add_range(&memblock.memory, base, size, nid, 0);
> +	return memblock_add_range(&memblock.memory, base, size, nid, flags);
>  }
>  
>  /**
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 917b3528636d..5f873e7f5b29 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1385,7 +1385,7 @@ int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
>  	mem_hotplug_begin();
>  
>  	if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
> -		ret = memblock_add_node(start, size, nid);
> +		ret = memblock_add_node(start, size, nid, MEMBLOCK_NONE);
>  		if (ret)
>  			goto error_mem_hotplug_end;
>  	}
> -- 
> 2.31.1
> 

-- 
Sincerely yours,
Mike.